JP2008173817A - Method and apparatus for resin molding - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a molding method of a resin molding preventing the expansion of a blow molded article from being obstructed, and a molding apparatus of the resin molded article. <P>SOLUTION: After a foamable resin 31 is injected in a hollow blow molded object 23 formed by the blow molding of a parison, the core part 13 of a mold 10 is moved so as to expand the volume of the cavity of the mold and the foaming of the foamable resin is accelerated to expand the blow molded object to mold the resin molded product. When the blow molded object is expanded by moving the core part, air is ejected to the stretched part of the blow molded object from the molding surface part 14b of the mold corresponding to the stretched part 23a of the blow molded object to form a gap part 16a between the molding surface part of the mold corresponding to the stretched part of the blow molded object and the stretched part of the blow molded object. By this method, the transfer of heat to the mold from the blow molded object is suppressed. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a molding method and molding apparatus for a resin molded product.

  For example, in various industrial parts such as automobile parts, foamed resin molded articles having excellent characteristics such as lightness and heat insulation are widely used. However, in a resin molded product in which foamable resin is injected into a mold and foamed, bubbles formed in the skin layer, which is the outermost surface of the molded product, break up, causing problems such as poor appearance There is.

  On the other hand, as a means for improving the surface properties of a resin molded product made of a foamable resin, after a parison made of a molten resin is suspended in a mold, the parison is sandwiched between molds and a gas such as air is introduced. There is known a molding method of a resin molded product in which hollow molding (so-called blow molding) and foam molding combined with blow molding are combined. For example, in Patent Document 1, a foamed thermoplastic resin piece is filled in a hollow molded body formed by blow molding a parison having a thermoplastic resin foam layer, and the foam piece is heated to fill the foam piece. A skin-molded foam-molded article obtained by fusing each other and a method for producing the same are disclosed.

In addition, as a method of molding a resin molded product using a foamable resin, a foamable resin containing a foaming agent in a resin is injected into a cavity of a pair of molds, which are a fixed mold and a movable mold, and then movable. There is also known a molding method (so-called core back method) in which foaming of a foamable resin is promoted by moving the mold in the mold opening direction to enlarge the volume of the cavity.
JP 2004-284149 A

  By the way, in the molding of a resin molded product in which a foamable resin is injected into a blow molded product formed by blow molding a parison and foaming of the foamable resin is promoted by a core back method, When the core part of the mold is moved to expand the volume of the mold, the foamed resin is promoted to expand and the blow molded body is expanded, the stretched part of the blow molded body is cooled by the mold and does not stretch. In some cases, the blow-molded body may be prevented from expanding. In such a case, for example, in the corner portion positioned at the peripheral edge portion of the cavity surface of the core portion, the resin molded product is not molded by following the movement of the core portion, which may cause problems such as poor appearance.

  Accordingly, the present invention has been made in view of the above technical problem, and can promote the foaming of the foamable resin to expand the blow molded body, and the blow molded body is accompanied with the expansion of the blow molded body. An object of the present invention is to provide a molding method and a molding apparatus for a resin molded product that can prevent the stretched portion from being cooled by a molding die and hindering the expansion of the blow molded article.

  For this reason, in the molding method of the resin molded product according to claim 1 of the present application, the parison made of solid resin is suspended in a mold that is opened, and the mold is closed after the parison is sandwiched between the parison. Blow molding to form a hollow blow molded body, and after forming the blow molded body, a foamable resin is injected into the blow molded body, and after the foamable resin is injected, the volume of the cavity of the mold is increased. A molding method for a resin molded product, in which the blow molded body is expanded by accelerating foaming of the foamable resin by moving the core portion of the mold by a predetermined amount as described above, When the blow molded body is expanded by moving, the component corresponding to the stretched portion of the blow molded body from the stretched portion of the blow molded body as the blow molded body expands. Taken suppressing heat transfer suppressing means that heat is transferred into the mold of the mold surface, the heat transfer from the blow molded article to the mold is obtained is characterized by being suppressed.

  Further, the invention method according to claim 2 of the present application is the invention method according to claim 1, wherein the core portion of the mold is moved by a predetermined amount from the time of closing the mold when the mold is closed with the parison interposed therebetween. Until the end of the core movement, the heat transfer suppression means is provided to suppress heat transfer from the blow molded body to the mold.

  Furthermore, the invention method according to claim 3 of the present application is the invention method according to claim 1 or 2, wherein the resin molded product is removed from the mold from the end of the core movement after the core portion of the mold is moved by a predetermined amount. The blow molding is performed by moving the core portion in a heat transfer suppression state in which heat transfer from the blow molded body to the mold is suppressed by the heat transfer suppression means until the molded product is removed. When the body is expanded, the heat transfer suppression means relaxes the heat transfer from the blow molded body to the mold, which is suppressed from the heat transfer suppressed state.

  Still further, the invention method according to claim 4 of the present application is the invention method according to claim 3, wherein the heat transfer suppression means is provided from the mold surface portion of the mold corresponding to the stretched portion of the blow molded body. Gas injection means for injecting gas to the stretched part of the blow molded body, and when the blow molded body is expanded by moving the core portion, a predetermined injection amount of gas is injected by the gas injection means, By forming a space between the stretched portion of the blow molded body and the mold surface portion of the mold corresponding to the stretched portion of the blow molded body, the blow molded body is transferred to the mold. Heat transfer is suppressed, and the amount of gas injected by the gas injection means is reduced from the predetermined injection amount or zero between the end of the core movement and the time of mold removal. As a result, a heat transfer suppression state in which heat transfer from the blow molded body to the mold is suppressed is performed from the blow molded body when the core is moved to expand the blow molded body. It is characterized in that the heat transfer to the mold is relaxed from the heat transfer suppression state.

  Furthermore, in the invention method according to claim 5 of the present application, in the invention method according to any one of claims 1 to 4, the foamable resin contains a reinforcing fiber that reinforces the foamable resin. It is characterized by.

  Furthermore, the invention method according to claim 6 of the present application is characterized in that in the invention method according to any one of claims 1 to 5, the foamable resin contains a physical foaming agent. is there.

  Still further, an invention method according to claim 7 of the present application is characterized in that, in the invention method according to claim 6, the physical foaming agent is a fluid in a supercritical state.

  Furthermore, a molding apparatus for a resin molded product according to claim 8 of the present application includes a mold that can be opened and closed, an extrusion head that extrudes a parison made of a solid resin into the mold that is opened, and sandwiches the parison. Pressurized fluid supply means for supplying a pressurized fluid into the parison after closing the mold and forming a hollow blow molded body, injection means for injecting a foamable resin into the blow molded body, and the molding Core moving means for moving the core portion of the mold so as to increase the volume of the mold cavity, and after injecting the foamable resin into the blow molded body, the volume of the cavity of the mold is reduced. A molding apparatus for a resin molded product, wherein the core portion is moved so as to be expanded, and the foamed resin is promoted to expand to expand the blow molded product. Heat transfer suppression means for suppressing heat transfer from the stretched portion of the blow molded body to the mold surface portion of the mold corresponding to the stretched portion of the blow molded body in accordance with tension, and the heat transfer The suppressing means suppresses heat transfer from the blow molded body to the mold when the core portion is moved to expand the blow molded body.

  Still further, the invention according to claim 9 of the present application is the invention according to claim 8, wherein the heat transfer suppression means is configured such that the core portion of the mold is closed from the time of mold closing when the mold is closed with the parison interposed therebetween. The heat transfer from the blow molded body to the mold is suppressed until the end of the movement of the core after a predetermined amount is moved.

  Furthermore, the invention according to claim 10 of the present application is the invention according to claim 8 or 9, further comprising control means for controlling the operation of the heat transfer suppression means, wherein the control means includes the core portion of the mold. A heat transfer suppression state that suppresses heat transfer from the blow molded body to the mold during the period from the end of moving the core that has been moved by a predetermined amount to the time when the resin molded product is removed from the mold. The heat transfer suppression means is actuated so as to relax from a heat transfer suppression state that suppresses heat transfer from the blow molded body to the mold when the blow molded body is expanded by moving the core portion. It is characterized by controlling.

  Furthermore, in the invention according to claim 11 of the present application, in the invention according to claim 10, the heat transfer suppression means is configured to perform the blow molding from the mold surface portion of the molding die corresponding to the stretched portion of the blow molded body. Gas injection means for injecting gas to a stretched part of the body, wherein the control means injects a predetermined injection amount of gas when moving the core portion to expand the blow molded body, A space is formed between the stretched portion of the molded body and the mold surface portion of the mold corresponding to the stretched portion of the blow molded body to suppress heat transfer from the blow molded body to the mold. In addition, during the period from the end of the movement of the core to the time of demolding the molded product, the injection amount of the gas injected to the blow molded body is reduced from the predetermined injection amount or zero, To the mold The heat transfer suppression state that suppresses heat is more relaxed than the heat transfer suppression state that suppresses heat transfer from the blow molded body to the mold when the blow molded body is expanded by moving the core portion. The operation of the gas injection means is controlled.

  Furthermore, the invention according to claim 12 of the present application is the invention according to any one of claims 8 to 11, wherein the molding die includes a fixed die and a movable die, and the fixed die and the movable die are Any one of the molds closes the other mold of the fixed mold and the movable mold when the mold is closed, and an outer peripheral portion located on the outer periphery of the core portion of the mold, and the molding The core portion movable relative to the outer peripheral portion so as to increase the volume of the cavity of the mold, and the heat transfer suppression means is a portion where the blow molded body is stretched as the blow molded body expands It is provided in the mold surface part of the outer peripheral part corresponding to the above.

  According to the method for molding a resin molded product according to claim 1 of the present application, the blow molded body can be expanded by promoting foaming of the foamable resin, and the blow molded body is stretched along with the expansion of the blow molded body. It is possible to prevent the portion to be cooled from being cooled by the mold and hinder the expansion of the blow molded product, and it is possible to easily and reliably mold a resin molded product having excellent surface properties and physical properties.

  In addition, according to the invention method of claim 2 of the present application, it is possible to prevent the stretched portion of the blow molded body from being cooled as the blow molded body expands even before the core portion of the mold is moved. And the effect can be more effectively achieved.

  Furthermore, according to the invention method of claim 3 of the present application, cooling of the resin molded product can be promoted after molding the resin molded product, and the molding cycle time for molding the resin molded product can be shortened. is there.

  Still further, according to the invention method of claim 4 of the present application, the heat transfer suppression means is gas injection means for injecting gas from the mold surface portion of the mold to the blow molded body, and gas is injected from the gas injection means. By doing so, heat transfer from the blow molded body to the mold is suppressed, so that the above effect can be obtained by a relatively simple means.

  Furthermore, according to the inventive method of claim 5 of the present application, it is possible to further promote foaming of the foamable resin by a springback phenomenon of the reinforcing fiber contained in the foamable resin. In a resin molded product molded using a foamable resin containing reinforcing fibers, the reinforcing fibers are not exposed on the surface of the resin molded product and the surface appearance is not deteriorated. it can.

  Furthermore, according to the inventive method of claim 6 of the present application, since the foaming resin contains a physical foaming agent, a resin molded product having a fine foam cell diameter can be molded. The physical properties such as bending rigidity of the product can be further improved.

  Furthermore, according to the inventive method of claim 7 of the present application, since the physical foaming agent is a fluid in a supercritical state, a resin molded product having finer foam cells can be molded, and the above effect Can be achieved more effectively.

  Furthermore, according to the molding apparatus for a resin molded product according to claim 8 of the present application, the blow molded body can be expanded by promoting foaming of the foamable resin, and blow molding is performed along with the expansion of the blow molded body. It is possible to prevent the stretched part of the body from being cooled by the molding die and hindering the expansion of the blow molded body, and a resin molded product having excellent surface properties and physical properties can be easily and reliably molded.

  Furthermore, according to the invention according to claim 9 of the present application, it is possible to prevent the stretched portion of the blow molded body from being cooled with the expansion of the blow molded body even before the core portion of the mold is moved. And the effect can be more effectively achieved.

  Furthermore, according to the invention of claim 10 of the present application, the cooling of the resin molded product can be promoted after the resin molded product is molded, and the molding cycle time for molding the resin molded product can be shortened. is there.

  Still further, according to the invention according to claim 11 of the present application, the heat transfer suppression means is gas injection means for injecting gas from the mold surface portion of the mold to the blow molded body, and injects gas from the gas injection means. By suppressing heat transfer from the blow molded body to the mold, the above effect can be obtained by a relatively simple means.

  Furthermore, according to the invention of claim 12 of the present application, the above-mentioned effect can be obtained with a relatively simple structure without complicating the structure of the mold and its driving mechanism.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
FIG. 1 is a cross-sectional explanatory view showing a molding die and an extrusion head of a molding apparatus for a resin molded product according to a first embodiment of the present invention. As shown in FIG. 1, the molding apparatus 1 supplies a molding fluid 10 that can be opened and closed, an extrusion head 21 that extrudes a heated and melted first resin as a parison 20, and a pressurized fluid in the molding die 10. And a blow pin 25 as a pressurized fluid supply means. Further, as shown in FIG. 4 described later, the molding apparatus 1 includes an injection device 30 as an injection unit that injects a foamable resin containing a foaming agent into the second resin into the mold 10. .

  The mold 10 is composed of a fixed mold 11 and a movable mold 12, and by closing the fixed mold 11 and the movable mold 12, a cavity 16 corresponding to the desired shape of the resin molded product is formed in the mold 10. Is done. The movable mold 12 includes a core part 13 and an outer peripheral part 14 combined with the core part 13.

  FIG. 2 is a perspective view schematically showing the movable mold. FIG. 2 shows a state in which the core portion 13 is moved in the mold opening direction with respect to the outer peripheral portion 14. As shown in FIG. 2, the core portion 13 of the movable mold 12 includes a protruding portion 13 b that protrudes in a square shape from a plate-shaped portion 13 a that is formed in a substantially flat plate shape, and is perpendicular to the mold opening / closing direction of the mold 10. The outer peripheral portion 14 formed in a square frame shape according to the outer peripheral shape of the protruding portion 13b is fitted on the outer periphery of the protruding portion 13b in any direction.

  The movable mold 12 is configured such that the core portion 13 and the outer peripheral portion 14 can be integrally moved in the mold opening / closing direction with respect to the fixed mold 11, and the movable mold 12 is movable after the fixed mold 11 and the movable mold 12 are closed. In a state where the outer peripheral portion 14 of the mold 12 and the fixed mold 11 are closed, only the core portion 13 of the movable mold 12 is configured to be movable in the mold opening direction so as to increase the volume of the cavity 16 of the mold 10. Yes.

  Further, the molding apparatus 1 includes a gas injection device (not shown) that injects a gas such as air into the molding die 10, for injecting the gas from the gas injection device into the molding die 10. The injection path 14 a is provided on the outer peripheral portion 14 of the movable mold 12. The injection path 14a is provided with a porous member 15 having countless small holes therein. The porous member 15 is disposed in a concave portion 14 c formed in a concave shape on the mold surface portion 14 b of the outer peripheral portion 14, and constitutes a part of the mold surface portion 14 b of the outer peripheral portion 14. Thereby, the gas injected from the gas injection device is injected into the mold 10 through the injection path 14 a and the porous member 15. For example, a sintered member or the like can be used as the porous member 15.

  The blow pin 25 supplies pressurized gas such as compressed air into the molding die 10 as pressurized fluid supplied from a pressurized fluid supply source (not shown), and maintains the inside of the molding die 10 at a predetermined pressure. Can be done. Further, the blow pin 25 can exhaust air in the mold 10 in a state where the blow pin 25 is inserted into the mold 10. The fixed die 11 of the molding die 10 is provided with an insertion hole 26 through which the blow pin 25 is inserted, and the blow pin 25 is configured to be able to advance and retract within the insertion hole 26.

  The injection apparatus 30 is for injecting a foamable resin 31 into the mold 10 and includes a cylinder 33 for kneading and melting the second resin 32. A screw 34 is provided inside the cylinder 33, and a screw drive mechanism and an injection mechanism (both not shown) are connected to the rear end of the screw 34.

  In the injection device 30, the second resin 32 put in the cylinder 33 is sequentially heated and kneaded and melted by a heater (not shown) and a screw 34 provided around the cylinder 33. Then, the inert gas made supercritical from the cylinder 35 containing an inert gas such as carbon dioxide or nitrogen to the second resin 32 kneaded and melted via the supercritical fluid generator 36 is super Injected by a critical fluid injection device 37. Thereby, the foamable resin 31 which made the 2nd resin 32 contain the foaming agent is formed.

  The foamable resin 31 is injected into the mold 10 by the screw 34 being rotated by the screw drive mechanism and being injected by the injection mechanism. The mold 10, specifically the fixed mold 11, is provided with an injection path 17 that communicates with the nozzle 38 of the injection device 30 and injects the foamable resin 31 into the mold 10.

  Further, the molding apparatus 1 includes a control unit (not shown) that comprehensively controls the molding apparatus 1, and this control unit drives the opening / closing of the mold 10 and opens the core 13 of the mold 10. Direction moving mechanism, parison extrusion mechanism of extrusion head 21, operation mechanism of blow pin 25, pressurized fluid supply mechanism from blow pin 25, injection mechanism of foamable resin 31 of injection device 30, and gas injection from gas injection device Control the mechanism.

  The control unit is provided with a timer (not shown). As shown in FIG. 10 described later, the control unit adjusts the air injection timing according to the time from when the parison 20 is suspended. Control air injection amount. The control unit is configured with a microcomputer as a main part, for example.

Next, molding of a resin molded product using the molding apparatus 1 will be described.
First, in a state where the mold 10 is opened, the parison 20 made of the first resin heated and melted is dropped from the extrusion head 21 into the mold 10 in a cylindrical shape. As the first resin, for example, a non-foamed solid resin such as a thermoplastic resin can be used.

  Then, the core portion 13 and the outer peripheral portion 14 of the movable die 12 are integrally moved in the die closing direction with respect to the stationary die 11 to close the molding die 10, and the upper end side and the lower end side of the parison 20 are fixed to the stationary die 11. And the outer peripheral portion 14 of the movable mold 12. As a result, the space inside the parison 20 is closed, and the space 22 is formed inside the parison 20. Thereafter, pressurized gas is supplied into the space 22 of the parison 20 through the blow pin 25.

  FIG. 3 is a schematic explanatory view showing a state where pressurized gas is supplied to a parison located in the mold. The blow pin 25 is advanced, pressurized gas is supplied to the space 22 inside the parison 20 by the blow pin 25, and the parison 20 is blow-molded. The interior space of the parison 20 expands, and the parison 20 is hollow according to the cavity surface 11 a of the fixed mold 11, the cavity surface 13 c of the core part 13 of the movable mold 12, and the mold surface part 14 b of the outer peripheral part 14 of the movable mold 12. A blow molded body 23 is formed.

  FIG. 4 is a schematic explanatory view showing a state in which a foamable resin is injected into the mold. When the parison 20 suspended in the mold 10 is blow-molded, next, the supercritical fluid is contained in the space 22 in the blow-molded body 23 from the injection device 30 to the second resin 32. A foamable resin 31 is injected. As the second resin, for example, a thermoplastic resin such as polypropylene can be used.

A mechanism for injecting the foamable resin 31 from the injection device 30 into the space 22 in the blow molded body 23 will be described with reference to FIGS.
5 to 7 sequentially show the steps of injecting the foamable resin 31 from the injection device 30 into the space 22 in the blow molded body 23, and show the part A in FIG. FIG. 5 is an explanatory view showing a state in which the first valve body and the second valve body provided in the injection path are closed, and FIG. 6 is a diagram illustrating the opening of the first valve body provided in the injection path. FIG. 7 is an explanatory view showing a state in which the second valve body is closed, and FIG. 7 is an explanatory view showing a state in which the first valve body and the second valve body provided in the injection path are opened.

  As shown in FIG. 5, the injection path 17 provided in the fixed mold 11 communicates with a recess 11b formed in the cavity surface 11a, and a first valve body 51 is provided on the bottom side of the recess 11b. The first valve body 51 is connected to a drive cylinder 53 via a rod 52 and is configured to be movable in the vertical direction by operating the drive cylinder 53. The injection path 17 is closed by moving the first valve body 51 upward. Further, the injection path 17 is provided with a second valve body 54 configured to open and close the injection path 17 and move in the horizontal direction. In the inflow path 17, the foamable resin 31 can be injected into the mold 10 in a state where the first valve body 51 and the second valve body 54 are opened.

  When the pressurized gas is supplied to the space 22 in the parison 20 and the parison 20 is pressed against the cavity surface 11a in a state where the first valve body 51 and the second valve body 54 close the injection path 17, respectively. In the recess 11b, the parison 20 is pressed against the surface thereof in a U-shaped cross section, and the parison 20 is formed thin in this portion.

  Then, as shown in FIG. 6, after operating the drive cylinder 53 to move the first valve body 51 downward, pressurized gas is supplied via the blow pin 25 to increase the pressure in the space 22. Then, the parison 20 having a U-shaped cross section in the recess 11b is opened at the bottom 20a.

  Next, after the second valve body 54 is moved so as to open the injection path 17 and the space portion 22 and the injection path 17 are communicated with each other, as shown in FIG. Is injected into the space 22. 5 to 7 show an example of the injection of the foamable resin into the hollow blow-molded body 23 formed by blow-molding the parison 20, and foaming is performed by other suitable means. The functional resin 31 may be injected.

  In this way, when the foamable resin 31 is injected into the blow molded body 23, the air in the space 22 of the blow molded body 23 is discharged through the blow pins 25 as the foamable resin 31 is injected. The When the foamable resin 31 is filled into the blow molded body 23, the blow pin 25 is retracted, and then the cavity of the mold 10 is closed with the fixed mold 11 and the outer peripheral portion 14 of the movable mold 12 closed. Only the core portion 13 of the mold 10 is moved in the mold opening direction so as to increase the volume of 16.

  FIG. 8 is a schematic explanatory view showing a state in which the foamable resin injected into the mold is foam-molded. As shown in this figure, in the molding apparatus 1, the core portion 13 of the mold 10 is moved by a predetermined amount in the mold opening direction, that is, in the direction of the arrow X1, so as to increase the volume of the cavity 16 of the mold 10. Thereby, foaming of the foamable resin 31 is promoted, and the blow molded body 23 is expanded. Then, the foamable resin 31 in a molten state is cooled and solidified, and a resin molded product 24 in which the foamable resin 31 is injected and foamed into the blow molded body 23 is molded.

  Thus, after injecting the foamable resin 31 into the blow molded body 23, the core portion 13 of the molding die 10 is moved in the mold opening direction so as to expand the volume of the cavity 16 of the molding die 10, and resin molding is performed. When the product 24 is molded, the blow molded body 23 is cooled by the molding die 10, and when the core 13 is moved in the mold opening direction, the blow molded body 23 is not stretched in the mold opening direction, and the blow molded body 23 expands. For example, in the corner portion positioned at the peripheral edge portion of the cavity surface of the core portion 13, it may not be molded following the movement of the core portion, and problems such as poor appearance may occur. This problem is avoided by suppressing the heat from the blow molded body 23 to the mold 10.

  FIG. 9 is a cross-sectional explanatory view showing a state in which the core portion of the molding die is moved in the mold opening direction with respect to the portion B in FIG. 8. When the core part 13 of the mold 10 is moved in the mold opening direction so as to increase the volume of the cavity 16 of the mold 10, the blow molded body 23 is expanded in the mold opening direction, and the cavity surface 13c of the core part 13 is expanded. Specifically, the blow molded body 23 located in the vicinity of the peripheral edge portion 13d of the cavity surface 13c is stretched.

  In the molding apparatus 1, when the core portion 13 of the mold 10 is moved to expand the blow molded body 23, a predetermined injection amount of gas enters the mold 10 from the gas injection device through the injection path 14 a and the porous member 15. A portion 23a of the blow molded body 23 that is sprayed and expanded as the blow molded body 23 expands, and a mold surface portion 14b of the mold 10 corresponding to the stretched portion 23a of the blow molded body 23, specifically, A space portion 16a is formed between the blow molding body 23 and the mold surface portion 14b of the mold 10 facing the stretched portion 23a. When the blow molding body 23 is expanded by the space portion 16a, the blow molding body is formed. Heat transfer from 23 to the mold 10 is suppressed.

  When the control unit moves the core portion 13 to expand the blow molded body 23, the blow molded body is stretched from the mold surface portion 14a of the mold 10 corresponding to the stretched portion 23a of the blow molded body 23. The operation of the gas injection device is controlled so as to inject a predetermined injection amount of gas into the portion 23a to suppress heat transfer from the blow molded body 23 to the molding die 10.

  When the core portion 13 of the mold 10 is moved by a predetermined amount in the mold opening direction, the gas injection means is then used so as to eliminate the space portion 16a formed between the blow molded body 23 and the outer peripheral portion 13. The gas injection amount is gradually reduced from the predetermined injection amount when the core portion 13 is moved, and finally the gas injection amount is made zero, so that the flow from the blow molded body 23 to the molding die 10 is reduced. The heat transfer suppression state that suppresses heat is relaxed from the heat transfer suppression state that suppresses heat transfer from the blow molded body 23 to the mold 10 when the core portion 13 is moved. Then, the blow molded body 23 and the foamable resin 31 are cooled and solidified by the molding die, and the resin molded product 24 is molded.

  The control unit injects into the blow molded body 23 during the period from the end of moving the core after moving the core 13 of the mold 10 by a predetermined amount to the time when the resin molded product 24 is removed from the mold 10. The operation of the gas injection device is controlled so that the injection amount of the gas to be reduced is less than or equal to the predetermined injection amount when the core portion 13 is moved.

  In addition, about control of the said gas injection apparatus from the time of a core movement end to the time of molded product demolding, the injection quantity of the gas injected to the blow molded object 23 is the said from the time of a core movement end to the time of molded product demolding. Even if it is reduced from the predetermined injection amount or made zero, it should be reduced from the predetermined injection amount or made zero in at least a part of the period from the end of the core movement to the time of mold removal. May be.

  Further, the porous member 15 provided in the injection path 14a injects gas into the extended portion 23a of the blow molded body 23 through the porous member 15 when the core portion 13 of the mold 10 is moved in the mold opening direction. In addition, the mold 10 is formed in such a size as to cover the stretched portion 23 a of the blow molded body 23 in the mold opening direction of the mold 10.

  FIG. 10 is a pattern diagram showing the air injection timing of the gas injection device. As shown in this figure, in the gas injection device, the air injection timing at which gas is injected into the mold 10 is controlled by the control unit. When the core part 13 of the mold 10 is moved by a predetermined amount in the mold opening direction (core back) to expand the blow molded body 23, gas is injected into the mold 10.

  Thus, when the core part 13 of the shaping | molding die 10 is moved to a mold opening direction, and the blow molding 23 is expanded, the shaping | molding die 10 corresponding to the part 23a to which the blow molding 23 is extended | stretched by the said gas injection apparatus. A space 16a is formed between the mold surface part 14b of the mold 10 and the blow molded body 23 by injecting a predetermined injection amount of gas from the mold surface part 14b to the stretched portion 23a of the blow molded body 23. Further, it is possible to suppress the portion 23a of the blow molded body 23 from being cooled and solidified, and to maintain the spreadability of the blow molded body 23.

  Further, as shown in FIG. 10, blow molding is performed from the mold surface portion 14b of the molding die 10 corresponding to the stretched portion 23a of the blow molded body 23 by the gas injection device even before the movement of the core portion 13 in the mold opening direction. Gas is injected into the part 23a of the body 23 to be stretched. That is, the parison 20 is blow-molded from when the mold 10 is closed with the parison 20 interposed therebetween, and the foamable resin 31 is injected into the blow-molded body 23, and then the core portion of the mold 10. A predetermined amount of gas is injected by the gas injection device until the end of the movement of the core, which has moved 13 in the mold opening direction.

  Thus, before the core part 13 is moved in the mold opening direction by the gas injection by the gas injection device from the time when the mold 10 is closed until the end of the core movement when the core part 13 is moved. Also, in the expansion of the blow molded body 23, it is possible to prevent the stretched portion 23a of the blow molded body 23 from being cooled and solidified.

  On the other hand, during the period from the end of the core movement to the time when the molded product 10 is opened after the molding die 10 is opened, the molded product 10 is ejected to the blow molded body 23 by the gas injection device. The gas injection amount is gradually reduced from the predetermined injection amount, finally the gas injection amount is made zero, and the gas injection is stopped.

  Thus, during the period from the end of the core movement to the time of mold removal, the injection amount of the gas injected to the blow molded body 23 is reduced from the predetermined injection amount or zero, and the core portion 13 is moved. By relaxing the heat transfer suppression state that suppresses heat transfer from the blow molded body 23 to the mold 10 when the blow molded body 23 is expanded, cooling of the resin molded product is promoted after molding the resin molded product. It is possible to reduce the molding cycle time for molding the resin molded product.

  Further, when the parison 20 is suspended in the mold 10, the gas injection means stops the gas injection from the mold surface portion 14 b of the mold 10 to the stretched portion 23 a of the blow molded body 23. Yes. In FIG. 10, the air injection timing adjustment area from the time of mold closing to the time of blow molding is shown. This air injection timing adjustment area depends on the temperature characteristics of the resin, the resin temperature, the temperature of the mold, etc. It shows that the air injection timing can be adjusted within the adjustment range. The air injection timing adjustment area after the end of the core movement also indicates that the air injection timing can be adjusted within this adjustment area, and the air injection amount is gradually reduced and stopped within the adjustment area.

  In the molding apparatus 1 according to the first embodiment, when the foamable resin 31 is injected into the space portion 22 of the parison 20, the air in the space portion 22 is discharged through the blow pin 25, but the space portion 22 is defined. The parison 20 may be provided with a gas discharge hole for discharging the gas in the space 22.

  FIG. 11 is a schematic explanatory view showing a state in which pressurized gas is supplied to a parison located in a molding die of the molding apparatus in the molding apparatus for a resin molded product according to the second embodiment of the present invention, FIG. 12 is a schematic explanatory view showing a state in which a foamable resin is injected into a mold of the molding apparatus. In these drawings, components having the same configuration as the molding apparatus 1 described above and having the same functions are denoted by the same reference numerals, and further description thereof is omitted.

  In the molding apparatus according to the second embodiment, as shown in FIG. 11, the cavity surface 11a of the fixed mold 11 and the cavity surface 13c of the core part 13 of the movable mold 12 are movable with the mold 60 closed. A pin 61 is provided on the fixed mold 11 so as to protrude into a space formed by the mold surface part 14 b of the outer peripheral part 14 of the mold 12. The pin 61 has a front end formed in a tapered shape and a rear end attached to the movable plate 62. The movable plate 62 is configured to be movable back and forth with respect to the space by, for example, a drive cylinder.

  Further, in the mold 60, an exhaust path 64 for discharging gas in the space formed by the cavity surfaces 11a and 13c and the mold surface portion 14b is formed in the fixed mold 11, and this exhaust path 64 is formed by a movable plate. It is closed by advancing 62 and opened by retracting the movable plate 61.

  As described above, when the pressurized gas is supplied to the space portion 22 of the parison 20 and the parison 20 is pressed against the cavity surface 11a, the parison is in a state where the pin 61 is stuck in the parison 20 as shown in FIG. 20 is pressed against the cavity surface 11 a, and a gas exhaust hole 20 b is formed in the parison 20 by a pin 61.

  Then, when the foamable resin 31 is injected into the space 22, the blow pin 25 is retracted and the movable plate 62 is retracted as shown in FIG. 12. Thereby, with injection | pouring of the foamable resin 31, the gas in the space part 22 can be discharged | emitted through the exhaust path 64 from the gas exhaust hole 20b.

  In this embodiment, a fluid in a supercritical state is used as the foaming agent, but other physical foaming materials or chemical foaming agents can also be used. Moreover, in the said shaping | molding apparatus 1, the heat transfer suppression which suppresses that heat is transmitted from the part 23a extended of the blow molding 23 to the type | mold surface part 14b of the shaping | molding die 10 corresponding to the part 23a extended of the blow molding 23 is performed. As a means, the gas injection means comprising the gas injection means, the injection path 14a and the porous member 15 provided on the outer peripheral portion 14 is used, and heat transfer from the blow molded body 23 to the mold 10 is performed by a relatively simple means. Although it is suppressed, when the core 13 is moved to expand the blow molded body 23, heat is transferred from the stretched portion 23a of the blow molded body 23 to the mold surface portion of the mold corresponding to the portion 23a. The heat transfer from the blow molded body 23 to the mold may be suppressed by providing other heat transfer suppression means for suppressing the above.

  FIG. 13 is a cross-sectional explanatory view showing a main part of a molding die of a molding apparatus in a molding apparatus for a resin molded product according to a third embodiment of the present invention. In addition, in FIG. 13, the same code | symbol is attached | subjected about what has the structure similar to the shaping | molding die 10 of the shaping | molding apparatus 1 mentioned above, and performs the same effect | action, and the further description is abbreviate | omitted.

  In the molding apparatus according to the third embodiment, heat is transmitted from the blow molded body 23 to the molding die 10 to the outer peripheral portion 74 of the molding die 70 instead of the gas injection means of the molding device 1 as the heat transfer suppression means. A heat insulating member 75 for suppressing this is provided. The heat insulating member 75 is disposed in a concave portion 74 b formed in a concave shape on the mold surface portion 74 a of the outer peripheral portion 74, and constitutes a part of the mold surface portion 74 a of the outer peripheral portion 74. The heat insulating member 75 is formed of a material having heat insulating properties such as ceramic.

  As described above, when the core portion 13 of the movable die 72 is moved in the mold opening direction, that is, in the direction indicated by the arrow X2, the blow molded body 23 is expanded, the cavity surface 13c of the core portion 13, specifically, The blow molded body 23 positioned in the vicinity of the peripheral edge portion 13d of the cavity surface 13c is stretched, and a heat insulating member 75 is disposed on the outer periphery of the stretched portion 23a of the blow molded body 23.

  In this manner, by providing the heat insulating member 75 in the mold 10 corresponding to the portion 23a to which the blow molded body 23 is stretched, the stretched portion 23a of the blow molded body 23 is prevented from being cooled and solidified. Can do. In addition, you may make it affix a heat insulating member on the type | mold surface part 74a of the outer peripheral part 74 corresponding to the part 23a to which the blow molding 23 is extended | stretched.

  FIG. 14 is a cross-sectional explanatory view showing a main part of a molding die of a molding apparatus in a molding apparatus for a resin molded product according to a fourth embodiment of the present invention. In addition, in FIG. 14, the same code | symbol is attached | subjected about what has the structure similar to the shaping | molding die 10 of the shaping | molding apparatus 1 mentioned above, and performs the same effect | action, and the further description is abbreviate | omitted.

  In the molding apparatus according to the fourth embodiment, as the heat transfer suppressing means, the third resin 85 having higher heat insulation than the first resin forming the blow molded body 23 instead of the gas injection means of the molding apparatus 1. Is injected into the mold 80, and an injection path 84 a for injecting the third resin 85 from the injection apparatus 86 is provided on the outer periphery 84 of the mold 80.

  As described above, when the core part 13 of the movable mold 82 is moved in the mold opening direction, that is, in the direction indicated by the arrow X3, and the blow molded body 23 is expanded, the cavity surface 13c of the core part 13, The blow molded body 23 located in the vicinity of the peripheral edge portion 13d of the cavity surface 13c is stretched, and corresponds to the stretched portion 23a of the blow molded body 23 and the stretched portion 23a of the blow molded body 23 by the injection device 86. The third resin 85 is injected at a relatively low pressure so as not to prevent the expansion of the blow molded body 23 between the outer peripheral portion 84 and the mold surface portion 84b. The operation of the injection device 92 is controlled by the control unit.

  As described above, the third resin 85 having high heat insulation is injected between the portion 23a of the blow molded body 23 to be stretched and the mold surface portion 84b of the mold 80 corresponding to the portion 23a of the blow molded body 23 to be stretched. By doing, it can suppress that the part 23a by which the blow molding 23 is extended | stretched is cooled and solidified.

  In the molding apparatus according to the fourth embodiment, when the blow molded body 23 is expanded by moving the core portion 13 of the mold 80 in the mold opening direction and expanding the blow molded body 23, the blow molded body is expanded. The third resin 85 is injected between the portion 23 a to be stretched 23 and the mold surface portion 84 b of the mold 80 corresponding to the portion 23 a to be stretched of the blow molded body 23. However, the stretched portion 23a of the blow molded body 23 may be formed of a highly heat-insulating resin as the blow molded body 23 expands.

  When a resin material containing a first resin and a third resin having a higher heat insulating property than the first resin is used and the resin material is melted and extruded from the extrusion head as a parison, the parison is formed. When the foamable resin is injected into the blow molded body and then the core portion of the mold is moved to expand the blow molded body, the stretched portion of the blow molded body is formed from the third resin. The third resin may be contained in a predetermined portion of the parison so that the stretched portion of the blow molded body is formed of a highly heat-insulating resin.

  Thus, after the parison is blow-molded and the foamable resin is injected into the blow-molded body, the core portion of the mold is moved by a predetermined amount in the mold opening direction, and the foaming of the foamable resin is promoted to blow-molded body. When inflating, heat transfer from the stretched portion of the blow molded body to the mold can be suppressed.

  As is clear from the above description, in this embodiment, when the resin molded product 24 is molded, the blow molded body 23 is expanded when the core 13 of the mold 10 is moved to expand the blow molded body 23. By taking heat transfer suppression means for suppressing heat transfer from the mold to the mold 10, it is possible to promote foaming of the foamable resin 31 and expand the blow molded body 23, and with the expansion of the blow molded body 23. Thus, the stretched portion 23a of the blow molded body 23 can be prevented from being cooled by the mold 10 and the expansion of the blow molded body can be prevented, and a resin molded product having excellent surface properties and physical properties can be easily and reliably obtained. Can be molded.

  Also, before the core part 13 of the mold 10 is moved in the mold opening direction by taking the heat transfer suppression means from the time when the mold 10 is closed until the end of the movement of the core after moving the core part 13. Moreover, it can suppress that the part 23a by which the blow molding 23 is extended | stretched with expansion | swelling of the blow molding 23 can suppress, and can show | play the said effect more effectively.

  Further, since the foaming resin 31 contains a physical foaming agent, a resin molded product having a fine foam cell diameter can be molded, and the physical properties such as bending rigidity can be further improved in the resin molded product. it can.

  Furthermore, since the physical foaming agent is a fluid in a supercritical state, a resin molded product having even finer foam cells can be molded, and the above-described effect can be more effectively achieved.

  Furthermore, in the molding apparatus 1 according to the present embodiment, the above-described effects can be obtained with a relatively simple structure without complicating the structure of the molding die and its driving mechanism.

  When molding the resin molded product 24, the foamable resin 31 may further contain reinforcing fibers that reinforce the foamable resin 31. Thus, by making the foamable resin 31 contain reinforcing fibers, it is possible to further promote foaming of the foamable resin by the springback phenomenon of the fibers. Even when molding using a foamable resin containing reinforcing fibers, a resin molded product with good surface properties can be obtained without the reinforcing fibers being exposed to the surface of the resin molded product and deteriorating the surface appearance. Can do.

  In the present embodiment, the core portion 13 of the mold 10 moves in the mold opening direction to expand the blow molded body 23, and is transmitted to the mold surface portion 14 b of the outer peripheral portion 14 facing the stretched portion 23 a of the blow molded body 23. Although the heat suppression means is provided, when the core part of the mold is moved to expand the blow molded body so as to expand the volume of the cavity of the mold, the blow molded body is moved along with the movement of the core part. It is possible to use other molds in which the heat transfer suppression means is provided on the mold surface portion of the mold corresponding to the stretched part.

  As described above, the present invention is not limited to the illustrated embodiments, and it goes without saying that various improvements and design changes can be made without departing from the gist of the present invention.

  The present invention relates to molding of a resin molded product in which a foamable resin is injected into a blow molded body to cause foaming, and is suitably applied to molding of a resin molded product such as a trunk board assembled to a vehicle body, for example. Is possible.

It is a section explanatory view showing a forming die and an extrusion head of a molding device of a resin molded product concerning a 1st embodiment of the present invention. It is a perspective view which shows the said movable mold | type typically. It is a schematic explanatory drawing which shows the state by which pressurized gas was supplied to the parison located in the said shaping | molding die. It is a schematic explanatory drawing which shows the state by which foamable resin is inject | poured in the said shaping | molding die. It is explanatory drawing which shows the state which the 1st valve body and 2nd valve body which were provided in the said injection | pouring path | route closed. It is explanatory drawing which shows the state which the said 1st valve body provided in the said injection | pouring path | route opened and the said 2nd valve body closed. It is explanatory drawing which shows the state which the said 1st valve body and said 2nd valve body provided in the said injection | pouring path | route opened. It is a schematic explanatory drawing which shows the state by which foaming resin inject | poured in the said shaping | molding die was foam-molded. FIG. 9 is a cross-sectional explanatory view showing a state in which the core portion of the molding die is moved in the mold opening direction with respect to B portion in FIG. 8. It is a pattern diagram which shows the air injection timing of the said gas injection apparatus. In the molding apparatus of the resin molded product which concerns on the 2nd Embodiment of this invention, it is a schematic explanatory drawing which shows the state by which pressurized gas was supplied to the parison located in the shaping | molding die of this molding apparatus. It is a schematic explanatory drawing which shows the state by which foamable resin is inject | poured in the shaping | molding die of the said shaping | molding apparatus. In the molding apparatus of the resin molded product which concerns on the 3rd Embodiment of this invention, it is cross-sectional explanatory drawing which shows the principal part of the shaping | molding die of this molding apparatus. In the molding apparatus of the resin molded product which concerns on the 4th Embodiment of this invention, it is cross-sectional explanatory drawing which shows the principal part of the shaping | molding die of this molding apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Molding device 10, 60, 70, 80 Molding die 11 Fixed die 12, 72, 82 Movable die 13 Core part 14, 74, 84 Outer peripheral part 16 Cavity 16a Space part 20 Parison 21 Extrusion head 23 Blow molding 24 Resin molding 25 Blow pin 30 Injection device 31 Foamable resin

Claims (12)

A parison made of a solid resin is suspended in a mold that is opened, and after the mold is closed with the parison sandwiched, the parison is blow-molded to form a hollow blow-molded body. After forming, the foamable resin is injected into the blow molded body, and after the foamable resin is injected, the foaming core is moved by a predetermined amount so as to increase the volume of the cavity of the mold, thereby the foaming A method for molding a resin molded article that expands the blow molded body by promoting foaming of a functional resin,
When the blow molded body is expanded by moving the core portion, the molding corresponding to the stretched portion of the blow molded body from the stretched portion of the blow molded body as the blow molded body expands Taking heat transfer suppression means for suppressing heat transfer to the mold surface portion of the mold, heat transfer from the blow molded body to the mold is suppressed,
A method for molding a resin molded product.   From the time when the mold is closed with the parison sandwiched until the end of moving the core after moving the core portion of the mold by a predetermined amount, the heat transfer suppression means is provided, The method for molding a resin molded product according to claim 1, wherein heat transfer to the mold is suppressed.   During the period from the end of moving the core after moving the core part of the mold by a predetermined amount to the time of demolding the molded product where the resin molded product is taken out from the mold, the heat transfer suppression means removes the blow molded body from Heat transfer suppression state in which heat transfer to the mold is suppressed, when the core part is moved to expand the blow molded body, heat transfer from the blow molded body to the mold by the heat transfer suppression means The method for molding a resin molded product according to claim 1, wherein the heat transfer is suppressed from being suppressed. The heat transfer suppression means is a gas injection means for injecting a gas from a mold surface portion of the mold corresponding to a stretched portion of the blow molded body to a stretched portion of the blow molded body,
When the blow molded body is expanded by moving the core portion, a predetermined injection amount of gas is injected by the gas injection means, and the stretched portion of the blow molded body and the stretched portion of the blow molded body By forming a space between the mold surface portion of the mold corresponding to the above, heat transfer from the blow molded body to the mold is suppressed,
Between the end of moving the core and the time of demolding the molded product, the gas injection amount injected by the gas injection means is reduced from the predetermined injection amount or made zero, Heat transfer from the blow molded body to the mold when the core is moved and the blow molded body is expanded in a heat transfer suppression state where heat transfer from the blow molded body is suppressed to the mold. Relaxing from the suppressed heat transfer suppression state,
The method for molding a resin molded product according to claim 3.   The method for molding a resin molded product according to any one of claims 1 to 4, wherein the foamable resin contains reinforcing fibers that reinforce the foamable resin.   The method for molding a resin molded product according to claim 1, wherein the foamable resin contains a physical foaming agent.   The method for molding a resin molded product according to claim 6, wherein the physical foaming agent is a fluid in a supercritical state. A mold that can be opened and closed, an extrusion head that pushes a parison made of solid resin into the mold that has been opened, and a pressurized fluid is supplied into the parison after the mold is closed with the parison in between. Pressurized fluid supply means for forming a hollow blow molded body, injection means for injecting a foamable resin into the blow molded body, and moving the core portion of the mold so as to increase the volume of the mold cavity And a core moving means for injecting the foamable resin into the blow molded body, and then moving the core portion so as to expand the volume of the cavity of the mold, thereby foaming the foamable resin. A molding apparatus for a resin molded product that promotes and expands the blow molded article,
Heat transfer suppression means for suppressing heat transfer from a stretched portion of the blow molded body to a mold surface portion of the mold corresponding to the stretched portion of the blow molded body as the blow molded body expands; Prepared,
The heat transfer suppression means suppresses heat transfer from the blow molded body to the mold when the core portion is moved to expand the blow molded body.
An apparatus for molding a resin molded product.   The heat transfer suppression means is formed from the blow molded body from the time when the mold is closed with the parison in between the time when the mold is closed and the time when the core movement of the mold is moved by a predetermined amount. The apparatus for molding a resin molded product according to claim 8, wherein heat transfer to the mold is suppressed. Control means for controlling the operation of the heat transfer suppression means,
The control means is configured to perform the molding from the blow molded body between the end of the core movement after moving the core portion of the molding die by a predetermined amount and the time when the resin molded product is removed from the molding die. The heat transfer suppression state that suppresses heat transfer to the mold is more than the heat transfer suppression state that suppresses heat transfer from the blow molded body to the mold when the core part is moved to expand the blow molded body. Controlling the operation of the heat transfer suppression means to relax,
The apparatus for molding a resin molded product according to claim 8 or 9. The heat transfer suppression means is a gas injection means for injecting a gas from a mold surface portion of the mold corresponding to a stretched portion of the blow molded body to a stretched portion of the blow molded body,
The control means injects a predetermined injection amount of gas when moving the core portion to expand the blow molded body, and a stretched portion of the blow molded body and a stretched portion of the blow molded body A space is formed between the mold surface corresponding to the mold surface portion to suppress heat transfer from the blow molded body to the mold, and from the end of the movement of the core to the time of mold release. In the heat transfer suppression state, the injection amount of the gas injected to the blow molded body is reduced from the predetermined injection amount or zero, and the heat transfer suppression state for suppressing heat transfer from the blow molded body to the mold is Controlling the operation of the gas injection means so as to relax from the heat transfer suppression state that suppresses heat transfer from the blow molded body to the mold when the blow molded body is expanded by moving the core part,
The apparatus for molding a resin molded product according to claim 10. The mold has a fixed mold and a movable mold,
One of the fixed mold and the movable mold is closed with the other mold of the fixed mold and the movable mold when the mold is closed, and on the outer periphery of the core portion of the mold. An outer peripheral part located; and the core part movable with respect to the outer peripheral part so as to increase the volume of the cavity of the mold,
The heat transfer suppression means is provided on a mold surface portion of the outer peripheral portion corresponding to a portion where the blow molded body is stretched with expansion of the blow molded body.
The apparatus for molding a resin molded product according to any one of claims 8 to 11,

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