JP2009066941A - Molding method for foamed resin molded article - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the foaming in a foaming inhibition resin part which is caused by the lowering of resin pressure resulting from the core back of a movable core during the molding for a foamed resin molded article. <P>SOLUTION: In the molding method for the foamed resin molded article, a mold including the movable core 32 capable of the core back to form a porous resin part where the foam is grown in the foamed resin molded article and a fixed core 33 for forming the foam inhibition resin part where the growth of the foam is suppressed in the foamed resin molded article is used. A molten foamable resin R is filled in a cavity 42 of the mold and after that, the movable core 32 is moved back in a direction to which the volume of the cavity 42 is extended. The core back is carried out in a state that a part of the foamable resin R to be formed by the movable core 32 is set to be a porous resin part, a part opposed to the part of the foamable resin R to be formed by the movable core 32 in the part of the foamable resin R to be formed by the fixed core 33 is set to be the foaming inhibition resin part and an intermediate resin part is set between the porous resin part and the foaming inhibition resin part. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for molding a foamed resin molded product, and belongs to the technical field of resin molding.

  Conventionally, resin molded products manufactured by injection molding or the like using ABS (acrylonitrile, butadiene, styrene) resin, PP (polypropylene) resin, or the like as materials are used for automobile parts and the like. In that case, from the viewpoints of heat insulation, lightness, shock absorption, etc., resin molded products, for example, bubbles are generated in the resin using a physical foaming agent such as carbon dioxide or nitrogen or a chemical foaming agent such as sodium hydrogen carbonate. It may be a foamed resin molded article having a porous structure. Such a foamed resin molded product generally has a direction in which the volume of the cavity expands after filling a moldable cavity with a molten foamable resin (an unfoamed resin containing an unfoamed foaming agent). It is manufactured by core-backing the mold.

  By the way, such a foamed resin molded product may be fastened to, welded to, or matched with other resin parts or metal parts (fit or sandwich). At this time, it is desirable that the fastening portion, the welded portion, the mating portion, and the like of the foamed resin molded product are non-foamed or low-foamed foam-suppressing resin portions in which foaming is suppressed. Otherwise, since the strength of the porous resin part in which bubbles have grown is relatively weak, for example, when the fastening part is fastened by a fastener such as a bolt, the fastening part may be buckled or cracked. Because. For the same reason, for example, when force is applied to the welded portion after welding, the welded portion may be deformed or dropped. Further, for the same reason, for example, when a force is applied to the mating portion after the mating, the mating portion may be deformed or dropped. Furthermore, for the mating part, the porous resin part in which bubbles have grown has a relatively low dimensional accuracy due to sink marks or the like at the time of the core back. This is because it may occur.

  Therefore, in order to manufacture a foamed resin molded product having the fastening portion, the welded portion, the mating portion, and the like as described above, most of the foamed resin molded product is a porous resin portion in which bubbles have grown. It is necessary to manufacture a foamed resin molded article having a configuration in which the foaming suppression resin part in which the suppression is partially present.

  For this purpose, for example, it is proposed to apply the technique described in Patent Document 1. That is, as illustrated in FIG. 12A, the mold is composed of a fixed mold for clamping and opening and a movable mold, and the movable mold is a porous material in which bubbles are grown in the foamed resin molded product. A movable core that can be core-backed to form a resin part, and a stationary core to form a foam-suppressed resin part in which foam growth is suppressed among foamed resin molded products, and these fixed molds After filling the foamed resin in a molten state into the cavity formed by the movable core and the stationary core, the movable core is core-backed in the direction in which the volume of the cavity expands (see the white arrow in the figure).

  Alternatively, as illustrated in FIG. 13A, the stationary core can be disposed on the fixed mold side. However, in this case, the stationary core is also moved in the same direction and at the same speed together with the core back of the movable core so that the gap between the cavity forming surface of the movable core and the cavity forming surface of the stationary core facing each other is not widened. Required (see white arrow in the figure).

  Then, in any case, the portion of the foamable resin filled in the cavity by the core back of the movable core (in other words, the portion not shaped by the stationary core) of the foamable resin filled in the cavity is made of resin. As a result, the foaming agent contained in the foamable resin starts to foam and bubbles grow, and the porosity is relatively large (in other words, the resin density is relatively small). It becomes the quality resin part. On the other hand, the portion of the foamable resin filled in the cavity that is shaped by the stationary core that does not core back does not drop the pressure of the resin, and as a result, the foaming agent does not start foaming and bubbles grow. In other words, the foaming suppression resin portion has a relatively small porosity (in other words, a relatively high resin density).

JP-A-11-156881 (paragraph 0031)

  However, as described above, the present inventors use a mold including a movable core and an immovable core as described above to produce a foamed resin molded product having a configuration in which the porous resin portion and the foam suppression resin portion coexist. As a result of repeated research, the peripheral portion of the cavity forming surface of the stationary core (in other words, the portion of the foaming resin shaped by the movable core is close to the portion of the foamable resin shaped by the stationary core. It was found that there was a problem that the foaming agent started to foam and bubbles grew. As illustrated in FIGS. 12B and 13B, this is because the cavity formed by the movable core and the stationary core or the cavity formed by the stationary mold and the stationary core is continuous. The effect of the resin pressure drop that occurs in the part that is shaped in the case extends to the part that is shaped in the stationary core, and as a result, the core of the foam cell contained in the part shaped in the stationary core is the movable core. Because the foaming agent starts to foam at the peripheral edge of the cavity forming surface of the stationary core adjacent to the movable core or adjacent to the fixed mold (see the black arrow in the figure). It is thought that.

  Therefore, not all the parts shaped by the stationary core become the foam suppression resin part, but the parts shaped by the peripheral part of the cavity forming surface of the stationary core among the parts shaped by the stationary core (in other words, If this is the case, the porosity of the part closer to the part shaped by the movable core is higher than the porosity of the other part (in other words, the part opposite to the part shaped by the movable core). Increased (in other words, reduced resin density), and as a result, when the part shaped by the stationary core is used as a fastening part, welded part, mating part, etc. Such problems as buckling, cracking, deformation, dropout and backlash will occur.

  An object of the present invention is to cope with the above-described problems, and an object of the present invention is to suppress foaming from occurring in the foam suppression resin portion due to a decrease in resin pressure accompanying the core back of the movable core.

  In order to solve the above problems, the present invention uses the following means.

  That is, in the invention according to claim 1 of the present application, after filling the foamed resin in the molten state into the cavity of the mold, a part of the mold is core-backed in the direction in which the volume of the cavity expands to expand the foamed resin. A method for molding a molded product, wherein a movable core capable of core back for forming a porous resin part in which bubbles are grown in a foamed resin molded product and growth of bubbles in the foamed resin molded product are suppressed. Using a mold including a stationary core for forming the foam suppression resin portion, a filling step of filling a molten foamable resin into a cavity of the mold, and after the filling step, the volume of the cavity is A core back step of core-backing the movable core in an expanding direction, and in the core back step, the foamable resin portion shaped by the movable core is set in the porous resin portion and shaped by the stationary core Depart The part opposite to the part of the foamable resin formed by the movable core is set as the foaming suppression resin part, and the intermediate part between the porous resin part and the foaming suppression resin part. The movable core is core-backed with the resin portion set.

  Next, the invention according to claim 2 of the present application is the molding method for the foamed resin molded product according to claim 1, wherein the cavity forming surface is extended in a radial direction by a predetermined amount from the foam suppression resin portion. By using the core, the portion of the foamable resin that is shaped by the stationary core is the portion that is shaped by the extended portion, and the porosity of the porous resin portion is larger than the porosity of the foam-suppressing resin portion. A smaller intermediate resin portion is set.

  Next, invention of Claim 3 of this application is a shaping | molding method of the foamed resin molded product of Claim 1 or 2, Comprising: The said intermediate | middle resin part makes the said foaming suppression resin part the said porous resin part. It is characterized by being continuous in the circumferential direction around the foam suppression resin portion so as to be isolated from the foam.

  Next, the invention according to claim 4 of the present application is the method for molding a foamed resin molded article according to any one of claims 1 to 3, wherein the foamable resin in a molten state contains a physical foaming agent. It is characterized by containing.

  Next, the invention according to claim 5 of the present application is the method for molding a foamed resin molded article according to claim 4, wherein the physical foaming agent is a fluid in a supercritical state.

  First, according to the first aspect of the present invention, after filling a foamable resin in a molten state into a cavity of the mold, a part of the mold is core-backed in a direction in which the volume of the cavity expands to expand the foamed resin. In a method of molding a molded product, a foam including a movable core for forming a porous resin portion and a stationary core for forming a foam-inhibiting resin portion is used. Since the movable core is core-backed in the direction in which the volume of the cavity expands after filling with the porous resin, a foamed resin molded product having a configuration in which the porous resin portion and the foam suppression resin portion coexist is manufactured. It becomes.

  In addition, the core back of the movable core is shaped by the movable core out of the portion of the foamable resin shaped by the stationary core by setting the portion of the foamable resin shaped by the movable core as the porous resin portion. The part opposite to the part of the foamable resin (that is, the porous resin part) is set as the foam suppression resin part, and the intermediate resin part is set between the porous resin part and the foam suppression resin part. Since this is performed in a state, the foam suppression resin portion can be separated from the porous resin portion by this intermediate resin portion, and the foam suppression resin portion and the porous resin portion can be clearly separated, and as a result The drag force that the core of the foam cell contained in the part shaped by the stationary core is dragged to the side of the part shaped by the movable core is applied by the movable core among the parts shaped by the stationary core. The part opposite the part to be formed Chi, it can be reduced in the foam control resin portion), it is possible to suppress foaming from occurring in the foam control resin portion due to a decrease in the resin pressure caused by the core back of the movable core.

  In that case, according to the invention described in claim 2, the extension of the portion formed by the stationary core is formed by using the stationary core whose cavity forming surface is extended by a predetermined amount in the radial direction from the foam suppression resin portion. Since the part to be shaped in the part is set to an intermediate resin part whose porosity is larger than the porosity of the foam suppression resin part and smaller than the porosity of the porous resin part, the intermediate resin part is set with a simple configuration Thus, the specific operation is realized, and the effect of the invention of claim 1 is achieved.

  As other specific operations for setting the intermediate resin portion, for example, a restriction is provided in the cavity at the peripheral portion of the cavity forming surface of the stationary core, or in the cavity at the peripheral portion of the cavity forming surface of the stationary core. Examples include inserting another resin in a molten state, or locally cooling the foamable resin at the peripheral portion of the cavity forming surface of the stationary core to increase the viscosity of the resin only in that portion. In any of these parts, the drag force that the core of the foamed cell contained in the part shaped by the stationary core is dragged to the part shaped by the movable core is out of the parts shaped by the stationary core. It has the effect | action which reduces in the part on the opposite side to the part shaped with a movable core.

  Next, according to the invention described in claim 3, the intermediate resin portion is continuous in the circumferential direction around the foam suppression resin portion so as to isolate the foam suppression resin portion from the porous resin portion. The drag force by which the core of the foam cell contained in the part shaped by the core is dragged toward the part shaped by the movable core can be reduced over the entire circumference of the foam suppression resin part. The effect of the invention of item 1 or 2 will be more reliably exhibited.

  Next, according to the invention described in claim 4, since the physical foaming agent is contained in the foamable resin in the molten state, for example, the foaming pressure is higher than that of the chemical foaming agent, etc. While it is a situation where the phenomenon that the core of the foam cell contained in the part to be shaped is dragged to the side of the part shaped by the movable core is more likely to occur, the drag force can be reduced, By using a physical foaming agent, the foamed cell diameter inside the foamed resin molded product can be made relatively small, and physical properties such as rigidity of the foamed resin molded product can be improved.

  In that case, according to the invention described in claim 5, since the molten foamable resin contains a fluid in a supercritical state, the drag phenomenon is more likely to occur, The drag force can be reduced, and by using a fluid in a supercritical state, the foamed cell diameter inside the foamed resin molded product can be made even finer, such as the rigidity of the foamed resin molded product. It becomes possible to further improve the physical properties. Hereinafter, the present invention will be described in more detail through the best mode for carrying out the invention.

  FIG. 1 is an overall configuration diagram of a molding apparatus 10 for a foamed resin molded product according to a first embodiment of the present invention, showing a filling process, and FIG. 2 shows a core back process. The molding apparatus 10 includes an injection machine 20 and a molding die 30.

  The injection machine 20 injects a molten foamable resin R containing a physical foaming agent into a cavity 42 of a mold 30 in a clamped state. A base resin such as an ABS resin is injected into a cylinder. A hopper 21 for charging and a nozzle 24 for supplying a supercritical fluid as a physical foaming agent to the molten base resin kneaded in the cylinder are provided. A fluid in a supercritical state is generated from a cylinder 22 of an inert gas such as carbon dioxide or nitrogen through a supercritical fluid generator 23. Thereby, the foamable resin R in a molten state in which the physical foaming agent is contained in the base resin is obtained. The foamable resin R is injected into the cavity 42 of the mold 30 in a clamped state through a supply passage 41 formed in the fixed mold 31.

  Here, the fluid in a supercritical state is a fluid that exceeds a limit temperature (critical temperature) and pressure (critical pressure) at which gas and liquid can coexist, and the critical temperature is, for example, carbon dioxide The critical pressure is, for example, 7.4 MPa for carbon dioxide and 3.4 MPa for nitrogen. A fluid in a supercritical state has a density close to that of a liquid and has a fluidity similar to that of a gas. As a result, the resin moves actively in the base resin in a molten state, and diffuses and penetrates even deeply into the resin molecule, and can become a seed or nucleus of fine foaming.

  The mold 30 includes a fixed mold 31 and movable molds 32 and 33 that clamp and open each other. The movable type includes a movable core 32 that can be core-backed in a direction in which the volume of the cavity 42 increases, and a stationary core 33. The movable core 32 is for forming a porous resin part C (see FIG. 7) in which bubbles grow out of the foamed resin molded product 50 (see FIG. 3) described below. The immobile core 33 is for forming the foam suppression resin part A (see FIG. 7) in the foamed resin molded product 50 in which the growth of bubbles is suppressed.

  FIG. 3 is a front view of the foamed resin molded product 50 according to the present embodiment as viewed from the movable molds 32 and 33 side. The foamed resin molded product 50 is an automobile part and constitutes a door together with the inner panel 60 and the outer panel 70 as shown in FIG. In that case, the foamed resin molded product 50 is fastened to the metal inner panel 60. Therefore, the some fastening part 51 ... 51 is scattered in the peripheral part of the foamed resin molded product 50. FIG. The foamed resin molded product 50 is covered with a door trim (not shown).

  5A is an enlarged view of the fastening portion 51 of the foamed resin molded product 50 as viewed from the arrow V side in FIG. 4, and FIG. 5B is along the VI-VI line in FIG. 5A. It is sectional drawing. As shown in the figure, the fastening portion 51 is configured by a circular recess. Therefore, the portion of the foamed resin molded product 50 other than the fastening portion 51 has a relatively large thickness, and the bottom portion of the fastening portion 51 has a relatively small thickness. And the hole 51a is formed in the bottom part of this fastening part 51, and the foamed resin molded product 50 is fastened with the inner panel 60 with the volt | bolt 80 and the nut 90 through this hole 51a.

  FIG. 6 is an enlarged view of a main part of the molding die 30 for showing the molding operation of the foamed resin molded product 50 in stages.

  First, as shown in FIG. 6A, the fixed mold 31 and the movable mold (the movable core 32 and the non-moving core 33) are clamped. Here, the stationary core 33 is provided with a protruding portion 33 a for forming the hole 51 a of the fastening portion 51. Then, the projecting portion 33 a abuts on the fixed mold 31, whereby a cavity 42 is formed by the fixed mold 31, the movable core 32, and the stationary core 33.

  Next, as shown in FIG. 6B, the molten foamable resin R is filled into the cavity 42 by the injection machine 20 (filling step).

  Next, as shown in FIG. 6C, after the foamable resin R is filled into the cavity 42, the core back of the movable core 32 is started in the direction in which the volume of the cavity 42 increases (see the white arrow in the figure). ).

  Next, as shown in FIG. 6D, when the movable core 32 is core-backed by a predetermined amount, the core-back of the movable core 32 is finished.

  In addition, although not shown in figure, the hydraulic core etc. for core-backing the movable core 32 are provided.

  In this core back process, when the movable core 32 cores back, the portion of the foamable resin R filled in the cavity 42 that is shaped by the movable core 32 has a reduced pressure of the resin R. As a result, The foaming agent contained in the foamable resin R (in this case, a fluid in a supercritical state) starts to foam and bubbles grow, and as shown in FIG. 7, the porosity is relatively large (in other words, The resin density is relatively small).

  On the other hand, the portion of the foamable resin R filled in the cavity 42 that is shaped by the stationary core 33 that does not core back does not lower the pressure of the resin R, and as a result, the foaming agent does not start foaming. Bubbles do not grow, and as shown in FIG. 7, the foam suppression resin portion A has a relatively low porosity (in other words, a relatively high resin density).

  However, in this case, since the cavity 42 formed by the movable core 32 and the stationary core 33 is continuous, the effect of the resin pressure drop generated in the portion shaped by the movable core 32 is shaped by the stationary core 33. As a result, the core of the foamed cell contained in the portion shaped by the stationary core 33 is dragged toward the portion shaped by the movable core 32, so that the movable core 33 and the stationary core 33 are movable. In the vicinity of the boundary with the core 32, that is, in the portion of the foamable resin R shaped by the stationary core 33, the foaming agent foams in the portion near the portion of the foamable resin R shaped by the movable core 32. There is a concern that bubbles will grow after starting.

  Therefore, in the present embodiment, as shown in FIG. 7, this portion is set to an intermediate resin portion B between the porous resin portion C and the foam suppression resin portion A, and is shaped by the stationary core 33. Of the portion of the foamable resin R, the portion opposite to the portion of the foamable resin R shaped by the movable core 32, to which the drag force as described above did not act, is set as the foam suppression resin portion A. To do. The porosity of the intermediate resin part B is larger than the porosity of the foam suppression resin part A and smaller than the porosity of the porous resin part C (in other words, the resin density of the intermediate resin part B is equal to that of the foam suppression resin part A). It is smaller than the resin density and larger than the resin density of the porous resin portion C).

  Further, as shown in FIG. 8, the intermediate resin portion B is continuous in the circumferential direction around the foam suppression resin portion A so as to isolate the foam suppression resin portion A from the porous resin portion C.

  The head of the bolt 80 is seated on the bottom of the fastening portion 51 within the range of the foam suppression resin portion A (see FIG. 5B). That is, the cavity forming surface 33b (see FIG. 6A) of the stationary core 33 is extended by a predetermined amount in the radial direction from the foam suppression resin portion A (and thus the head of the bolt 80). The portion of the foamable resin R that is shaped by the stationary core 33 is used for the portion that is shaped by the extended portion, and the porosity is larger than the porosity of the foam suppression resin portion A, and the porous resin portion The intermediate resin portion B is smaller than the porosity of C.

  Thus, in this embodiment, after filling the foamed resin R in the molten state into the cavity 42 of the mold 30, a part of the mold (movable core 32) is placed in the direction in which the volume of the cavity 42 increases. A method of molding the foamed resin molded product 50 by core back is provided.

  In that case, a mold 30 including a movable core 32 for forming the porous resin portion C and a stationary core 33 for forming the foam suppression resin portion A is used and melted in the cavity 42 of the mold 30. After filling the foamable resin R in the state, the movable core 32 is core-backed in the direction in which the volume of the cavity 42 is expanded, so that the foaming of the configuration in which the porous resin portion C and the foam suppression resin portion A coexist. The resin molded product 50 is manufactured.

  In addition, the core back of the movable core 32 sets the portion of the foamable resin R shaped by the movable core 32 to the porous resin portion C, and among the portions of the foamable resin R shaped by the fixed core 33 The portion opposite to the portion of the foamable resin R (that is, the porous resin portion C) shaped by the movable core 32 is set as the foam suppression resin portion A, and the porous resin portion C and the foam suppression resin are set. Since the intermediate resin part B is set between the part A and the intermediate resin part B, the foaming suppression resin part A can be separated from the porous resin part C by the intermediate resin part B. And the porous resin portion C can be clearly separated. As a result, the core of the foam cell contained in the portion shaped by the stationary core 33 is moved to the side shaped by the movable core 32. The drag force that is dragged is shaped by the stationary core 33. It can be reduced in the portion of the portion opposite to the portion shaped by the movable core 32 (that is, the foam suppression resin portion A), and due to the decrease in the resin pressure accompanying the core back of the movable core 32 It is possible to prevent foaming from occurring in the foam suppression resin portion A.

  In that case, a portion formed by the extension portion among the portions formed by the fixed core 33 using the fixed core 33 in which the cavity forming surface 33b is extended by a predetermined amount in the radial direction from the foam suppression resin portion A. Is set to the intermediate resin part B whose porosity is larger than the porosity of the foam suppression resin part A and smaller than the porosity of the porous resin part C, so that the intermediate resin part B is set with a simple configuration. Since the operation is realized, the drag force that causes the core of the foam cell contained in the portion shaped by the stationary core 33 to be dragged toward the portion shaped by the movable core 32 is shaped by the stationary core 33. The effect | action which reduces in the part on the opposite side to the part shaped with the movable core 32 among the parts to be performed will be acquired.

  Further, since the intermediate resin portion B is continuous in the circumferential direction around the foam suppression resin portion A so as to isolate the foam suppression resin portion A from the porous resin portion C, the portion formed by the stationary core 33 The drag force by which the core of the foam cell contained in the foam core is dragged toward the portion formed by the movable core 32 can be reduced over the entire circumference of the foam suppression resin portion A. It is possible to more reliably prevent foaming from occurring in the foam suppression resin portion A due to a decrease in the resin pressure accompanying the core back.

  Moreover, since the foaming resin R in the molten state contains a physical foaming agent, for example, the foaming pressure is higher than that of a chemical foaming agent or the like. While the phenomenon in which the core of the core is dragged toward the portion formed by the movable core 32 is more likely to occur, the drag force can be reduced and a foamed resin molded product can be obtained by using a physical foaming agent. The foam cell diameter inside 50 can be made to be a relatively small diameter, and physical properties such as rigidity of the foamed resin molded product 50 can be improved.

  In this case, since the fluid in the supercritical state is used as the physical foaming agent, the drag force can be reduced while the drag phenomenon is more likely to occur, and the fluid in the supercritical state is used. As a result, the foamed cell diameter inside the foamed resin molded product 50 can be made even finer, and physical properties such as rigidity of the foamed resin molded product 50 can be further improved.

  The molten foamable resin R may further contain reinforcing fibers such as glass fibers. The physical properties such as the strength of the foamed resin molded product 50 can be improved, and when the movable core 32 is core-backed, a springback phenomenon of the reinforcing fiber occurs, which causes foaming or expansion of the foamable resin R. The advantage of being further promoted is obtained.

  Next, a second embodiment of the present invention will be described with reference to FIGS. However, the description of the same or similar parts as those in the first embodiment will be omitted, and only the characteristic parts of the second embodiment will be described. The same reference numerals are used for the same or similar components as those in the first embodiment.

  FIGS. 9A and 9B are enlarged views of the mating portion 100 of the foamed resin molded product 50 according to the second embodiment. The difference from the first embodiment is that a square recess mating portion 100 is provided instead of the circular recess fastening portion 51.

  The mating portion 100 is open to the peripheral edge side of the foamed resin molded product 50, and the mating member 110 and the mating portion 100 are sandwiched from the open side. In that case, the counterpart member 110 is sandwiched between the mating portion 100 within the range of the foam suppression resin portion A.

  FIG. 10 is an enlarged view of a main part of the mold 30 for showing stepwise the molding operation of the foamed resin molded product 50 according to the second embodiment.

  First, as shown in FIG. 10A, the fixed mold 31 and the movable mold (the movable core 32 and the non-moving core 33) are clamped. Here, a cavity 42 is formed by the fixed mold 31, the movable core 32, and the stationary core 33.

  Next, as shown in FIG. 10B, the molten foamable resin R is filled in the cavity 42 by the injection machine 20 (filling step).

  Next, as shown in FIG. 10C, after filling the foaming resin R into the cavity 42, the core back of the movable core 32 is started in the direction in which the volume of the cavity 42 increases (see the white arrow in the figure). ).

  Next, as shown in FIG. 10D, when the movable core 32 is core-backed by a predetermined amount, the core-back of the movable core 32 is finished.

  In this core back process, as shown in FIGS. 9A and 9B, the portion formed by the movable core 32 has a relatively high porosity (in other words, a relatively low resin density). ) Porous resin part C.

  On the other hand, among the portions shaped by the stationary core 33, the portion opposite to the portion shaped by the movable core 32 has a relatively low porosity as shown in FIGS. 9 (a) and 9 (b). The foam suppression resin portion A is small (in other words, the resin density is relatively large).

  And the part between these porous resin parts C and the foam suppression resin part A is the intermediate resin part B with a porosity larger than the porosity of the foam suppression resin part A and smaller than the porosity of the porous resin part C. Become.

  The specific example described above is an example in which the stationary core 33 is arranged on the movable side as shown in FIGS. 1 and 2. However, the present invention is not limited to this, and depending on the situation, FIG. As shown in (a) and (b), the stationary core 33 can be disposed on the fixed mold 31 side. However, in this case, the gap between the cavity forming surface of the movable core 32 and the cavity forming surface of the stationary core 33 facing each other is not widened (in other words, the movable core 32 and the stationary core 33 that are in contact with each other) A feature is that, together with the core back of the movable core 32, the stationary core 33 is also moved in the same direction at the same speed (see the white arrow in the figure).

  The above embodiment is the best embodiment of the present invention, but it goes without saying that various modifications and changes may be made without departing from the scope of the claims.

  For example, instead of the fastening part 51 and the mating part 100, a welding part welded to the mating member can be used. Further, the mating portion 100 may be a mating mating portion instead of the mating mating portion.

  As described above in detail with reference to specific examples, in the present invention, during the molding of the foamed resin molded product, foaming occurs in the foam suppression resin portion due to a decrease in the resin pressure accompanying the core back of the movable core. Therefore, a wide range of industrial applicability is expected in the technical field of resin molding.

BRIEF DESCRIPTION OF THE DRAWINGS It is a whole block diagram of the shaping | molding apparatus of the foamed resin molded product which concerns on the 1st Embodiment of this invention, Comprising: A filling process is shown. Similarly, a core back process is shown. It is a front view from the movable mold side of the foamed resin molded product shape | molded with the said shaping | molding apparatus. It is a longitudinal cross-sectional view which follows the IV-IV line | wire of FIG. 3, Comprising: A foamed resin molded product shows the state fastened with other components. (A) is an enlarged view of the fastening part of the foaming resin molded product seen from the arrow V side of FIG. 4, (b) is sectional drawing which follows the VI-VI line of FIG. 5 (a). It is the principal part enlarged view of the shaping | molding die for showing the shaping | molding operation | movement of the said shaping | molding apparatus in steps, Comprising: (a) shows the state which the fixed mold | type and the movable mold clamped, (b) is a shaping | molding. A state in which the mold cavity is filled with a foamable resin in a molten state, (c) is a state in which the core back of the movable core is started after filling the foamable resin, and (d) is a movable core This shows a state in which the core back is finished. It is an expanded sectional view similar to FIG.5 (b) for showing the fastening part of the foamed resin molded product shape | molded by the said shaping | molding operation | movement, and its periphery structure. Similarly, it is an enlarged front view similar to FIG. It is an enlarged view of the fitting part of the foamed resin molded product which concerns on the 2nd Embodiment of this invention, Comprising: (a) corresponds to Fig.5 (a), (b) is FIG.9 (a). FIG. 5 is a cross-sectional view taken along line IX-IX of FIG. 5 and corresponds to FIG. It is the principal part enlarged view of the shaping | molding die for showing the shaping | molding operation | movement of the shaping | molding apparatus which concerns on the 2nd Embodiment of this invention in steps, Comprising: (a) is the state which the fixed type | mold and the movable type | mold clamped (B) shows a state in which a moldable cavity is filled with a foamable resin in a molten state, and (c) shows a state in which the core back of the movable core is started after filling with the foamable resin. (D) shows a state in which the core back of the movable core is finished. It is a fragmentary view similar to FIG.1 and FIG.2 which shows the modification of arrangement | positioning of a stationary core. It is explanatory drawing of the subject which this invention tends to solve, Comprising: (a) shows the state which is made into an ideal, (b) shows the state containing the conventional malfunction. It is another explanatory drawing of the subject which the present invention is going to solve, and (a) shows the ideal state and (b) shows the state containing the conventional fault.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Molding apparatus 20 Injection machine 30 Molding die 31 Fixed mold 32 Movable core (moving type)
33 Immovable core (moving type)
33b Cavity forming surface 42 Cavity 50 Foamed resin molded product 51 Fastening portion 60 Inner panel 80 Bolt 90 Nut 100 Matching portion 110 Mating member A Foaming suppression resin portion B Intermediate resin portion C Porous resin portion R Foamable resin

Claims (5)

A method of molding a foamed resin molded product by filling a molten foamable resin into a cavity of a mold and then core-backing a part of the mold in a direction in which the volume of the cavity expands,
A movable core that can be core-backed to form a porous resin part in which foam has grown in a foamed resin molded product, and an immobilization to form a foam-inhibited resin part in which foam growth is suppressed in the foamed resin molded product. Using a mold that includes a core,
A filling step of filling a molten foamable resin into the cavity of the mold;
A core back step of core back the movable core in a direction in which the volume of the cavity expands after the filling step;
In the core back process, the foamable resin portion shaped by the movable core is set as the porous resin portion, and the foam shaped by the movable core among the foamable resin portions shaped by the stationary core. The movable core is core-backed in a state where the part opposite to the resin part is set as the foam suppression resin part and an intermediate resin part is set between the porous resin part and the foam suppression resin part. A method for molding a foamed resin molded product. A method for molding a foamed resin molded article according to claim 1,
By using a stationary core in which the cavity forming surface is extended by a predetermined amount in the radial direction from the foam suppression resin portion, a portion shaped by the extended portion of the portion of the foamable resin shaped by the stationary core, A method for molding a foamed resin molded product, characterized in that the porosity is set to an intermediate resin portion larger than the porosity of the foam-suppressing resin portion and smaller than the porosity of the porous resin portion. A method for molding a foamed resin molded product according to claim 1 or 2,
The intermediate resin portion is continuous in the circumferential direction around the foam suppression resin portion so as to isolate the foam suppression resin portion from the porous resin portion. . A method for molding a foamed resin molded article according to any one of claims 1 to 3,
The method for molding a foamed resin molded product, wherein the foamable resin in a molten state contains a physical foaming agent. A method for molding a foamed resin molded product according to claim 4,
The method for molding a foamed resin molded product, wherein the physical foaming agent is a fluid in a supercritical state.

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