JP5169281B2 - Molding method and molding apparatus for foamed resin molded product - Google Patents

Description

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

  Conventionally, resin molded products molded 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., the resin molded product is made of bubbles in the resin using a physical foaming agent such as carbon dioxide or nitrogen or a chemical foaming agent such as sodium hydrogen carbonate. The produced foamed resin molded article may have a porous structure.

  For example, as described in Patent Document 1, such a foamed resin molded article is a foamed resin in a molten state (before foaming in which an unfoamed foaming agent is mixed with a base resin in a molten state). After the resin is filled, the mold is core-backed in the direction in which the volume of the cavity increases, more specifically in the direction in which the thickness of the molded product increases.

  The foamed resin molded product thus molded has a shape when viewed from the core back direction (hereinafter sometimes referred to as “planar shape” for the sake of convenience) while maintaining the cavity shape, and a direction orthogonal to the core back direction. When viewed from above, the shape, that is, the thickness expands several times as much as before the core back due to the core back of the mold and the foaming of the resin.

JP-A-11-156881 (paragraph 0031)

  However, the present inventors have studied and studied in detail the molding of the foamed resin molded product by the core back of the mold, and more specifically, the edge of the planar shape of the foamed resin molded product after molding, more specifically, Including the outer peripheral edge of the molded product, the edge of the notch partially provided on the outer periphery of the molded product, or the peripheral edge of the opening provided in the molded product separated from the outer periphery of the molded product, etc. The molded product is shrunk inward, and as a result, the overall size of the molded product in the planar shape is smaller than the target size, and the size of the opening and notch is larger than the target size. I encountered the problem of poor shape of foamed resin molded products.

  As a result, the dimensional accuracy of the foamed resin molded product in the planar shape is reduced. For example, if an attempt is made to fit the molded product to the mating member using an opening, the molded product will be disengaged, or a molded product using a notch. Even if an attempt is made to fit or position the mating member on the mating member, play will occur.

  Such a phenomenon is considered to occur for the following reasons. That is, when the core back after filling the melted foamable resin into the cavity, the surface layer of the foamable resin in the cavity (the part in contact with the cavity forming surface of the mold) has sufficient extensibility. The foamable resin expands due to internal foaming, and the surface layer part receives pressure from the inside of the foam and is pressed against the cavity forming surface. Even if the cavity volume is increased by the core back, the surface layer part is in the increasing cavity. Following this, a foamed resin molded product that maintains the cavity shape after the core back is obtained.

  However, in reality, when the core back is started or during the core back, the surface layer portion of the foamable resin in contact with the cavity forming surface of the mold is cooled, the extensibility is lowered, and the foam pressure from the inside is received. Is in a state that is difficult to expand. As a result, the surface layer part does not sufficiently follow the cavity whose volume increases with the core back, and the pressure receiving area of the foaming pressure from the inside is relatively small, that is, the end face of the outer peripheral part constituting the thickness of the molded product Further, the end face of the notch edge or the end face of the peripheral edge of the opening moves so as to be drawn inward of the molded product at the time of core back, and is degenerated.

  The present invention addresses the above-described problems that occur when a molded mold is molded back with a core back of the mold, and the foamed resin is caused by the shrinkage of the molded product edge along the core back to the inside of the molded product. It is an object to suppress the problem of the shape defect of a molded product or the problem of a decrease in dimensional accuracy in a planar shape.

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

That is, the invention according to claim 1 of the present application is a method for molding a foamed resin molded article in which a mold mold cavity is filled with a foamed resin in a molten state, and then the mold is core-backed. The main space formed up to the position of the edge of the molded product when the foamed resin molded product after molding is viewed from the core back direction, and a predetermined amount from the position to the outside of the molded product continuously in the main space When the foaming resin is used, the position of the cavity exceeds a predetermined amount from the main space side to the subspace side, and the foamable resin is placed in the main space and the subspace of the cavity. In the core back of the mold, the temperature of the foamable resin filled in the subspace among the foamable resin filled in the mold cavity is set higher than the temperature of the foamable resin filled in the main space. Characterized by

  Here, the “predetermined amount” in which the subspace of the cavity is extended increases as the core back distance increases.

Next, the invention according to claim 2 of the present application is the method for molding a foamed resin molded article according to claim 1 , wherein the temperature of the cavity forming surface of the subspace among the cavity forming surfaces of the mold is set. By making it higher than the temperature of the cavity formation surface of the main space, the temperature of the foamable resin filled in the subspace is made higher than the temperature of the foamable resin filled in the main space.

Next, the invention according to claim 3 of the present application is the method for molding a foamed resin molded product according to claim 1 or 2 , wherein the edge portion is a notch provided on the outer periphery of the molded product. It is a peripheral part of the opening provided in the edge part and / or the molded article.

Next, the invention described in claim 4 of the present application is the method for molding a foamed resin molded product according to any one of claims 1 to 3 , wherein a physical foaming agent is added to the base resin in a molten state. The molten foamable resin is produced by mixing.

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 a fluid in a supercritical state is used as the physical foaming agent.

On the other hand, the invention described in claim 6 of the present application is a filling means for filling the mold cavity with a foamable resin in a molten state, and a core for core-backing the mold after filling with the foamable resin by the filling means. A molding apparatus for a foamed resin molded product having a back means, wherein the cavity is formed up to a position of an edge of the molded product when the foamed resin molded product after molding is viewed from the core back direction. And a subspace extending from the position to the outside of the molded product by a predetermined amount continuously from the position, and the foamability filled in the cavity of the mold during the core back by the core back means Resin temperature setting means is provided for making the temperature of the foamable resin filled in the subspace out of the resin higher than the temperature of the foamable resin filled in the main space .

  Here, the “predetermined amount” in which the subspace of the cavity is extended increases as the core back distance increases.

Next, the invention according to claim 7 of the present application is the molding apparatus for the foamed resin molded product according to claim 6 , wherein the resin temperature setting means is a subspace of the cavity forming surface of the mold. The temperature of the cavity forming surface is made higher than the temperature of the cavity forming surface of the main space.

Next, the invention according to claim 8 of the present application is the molding apparatus for the foamed resin molded product according to claim 6 or 7 , wherein the edge portion is a notch provided on the outer periphery of the molded product. It is a peripheral part of the opening provided in the edge part and / or the molded article.

Next, the invention according to claim 9 of the present application is the molding apparatus for the foamed resin molded product according to any one of claims 6 to 8 , in order to produce the foamable resin in the molten state. A foaming agent supply means for mixing a physical foaming agent with the base resin in a molten state is provided.

Next, the invention according to claim 10 of the present application is the molding apparatus for the foamed resin molded product according to claim 9 , wherein the foaming agent supply means supplies a fluid in a supercritical state as the physical foaming agent. It is characterized by mixing.

First, according to the first and sixth aspects of the invention, in the case of molding a foamed resin molded product by core-backing the mold, molding that occurs in advance at the time of core-back at the time of filling the molten foamable resin Taking into account the shrinkage of the product edge to the inside of the molded product, the position of the edge of the molded product when viewed from the core back direction (hereinafter referred to as the “target position” for convenience) The foamed resin is filled into the cavity by a predetermined amount beyond the outside of the molded product. At the start of the core back, the edge of the molded product of the foamed resin filled in the cavity is removed. The foamable resin in the subspace to be formed is present outside the molded product from the target position. Therefore, even if the edge of the molded product shrinks inward during the core back, the problem of poor shape of the foamed resin molded product due to the shrinkage or the problem of reduced dimensional accuracy in the planar shape is suppressed. It becomes.

Further , according to these inventions , the core back is performed in a state where the temperature of the foamable resin in the subspace filled in the cavity beyond the target position is higher than the temperature of the foamable resin filled in the main space. Therefore, the lowering of the stretchability of the surface layer portion of the foamable resin in the subspace that forms the edge portion of the molded product is suppressed, and the degree of degeneration of the edge portion of the molded product is reduced. Accordingly, it is possible to reduce the amount of the foamable resin that fills the subspace beyond the target position, and to further suppress the problem of the shape failure of the foamed resin molded product or the problem of the decrease in dimensional accuracy in the planar shape. Will be.

In that case, according to the inventions of claim 2 and claim 7 , for example, the temperature of the cavity forming surface of the mold is not directly inserted into the foamable resin filled in the cavity. It is possible to make the temperature of the foamable resin filled in the subspace beyond the target position higher than the temperature of the foamable resin filled in the main space easily and reliably.

Next, according to the invention described in claims 3 and 8 , the size of the notch and / or the opening provided in the outer periphery of the molded product is larger than the target size. As a result, a foamed resin molded product with high dimensional accuracy in the planar shape of the notch and / or the opening is obtained, and the molded product using the opening and the mating member are obtained. It is possible to satisfactorily perform fitting, fitting and positioning between the molded product and the counterpart member using the notch.

Next, according to the inventions of claims 4 and 9 , since the foamed resin in the molten state is produced by mixing the physical foaming agent with the base resin in the molten state, for example, chemical foaming. The foaming ratio is higher than that of the agent, the core back distance is long, and the edge of the molded product is more likely to shrink. The problem of reduced dimensional accuracy will be suppressed. Further, for example, the foamed cell diameter inside the foamed resin molded product can be made relatively small compared to a chemical foaming agent, and the physical properties such as rigidity of the foamed resin molded product can be improved. .

In that case, according to the inventions of claims 5 and 10 , since the fluid in the supercritical state is used as the physical foaming agent, the foaming ratio is higher, the core back distance is longer, Although the edge is more likely to shrink, the problem of the shape failure of the foamed resin molded product due to the shrinkage or the problem of dimensional accuracy deterioration in the planar shape is suppressed. In addition, the foamed cell diameter inside the foamed resin molded product can be made even finer, and physical properties such as rigidity of the foamed resin molded product can be further improved. 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 50 according to the best embodiment of the present invention, where (a) shows a filling process and (b) shows a core back process. It is. The molding apparatus 10 includes an injection machine 20 as a filling unit and a molding die 30. The molding operation of the foamed resin molded product 50 performed using the molding apparatus 10 constitutes the molding method of the foamed resin molded product 50 according to the present invention.

  The injection machine 20 injects and fills a molten foamable resin 40 containing a physical foaming agent into a cavity 33 of a mold 30 in a clamped state as shown in FIG. For example, a hopper 21 for introducing a base resin such as PP resin, and a nozzle 24 for supplying a supercritical fluid as a physical foaming agent to a molten base resin kneaded in a cylinder. (Foaming agent supply means). 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 40 in the molten state obtained by mixing the physical foaming agent with the base resin in the molten state is obtained. The foamable resin 40 is injected and filled into the cavity 33 of the mold 30 in a clamped state through a supply passage 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 is composed of a fixed mold 31 and a movable mold 32 that clamp and open each other. The movable mold 32 is configured to move back for mold clamping and mold opening, and can be core-backed in a direction in which the volume of the cavity 33 increases. And the hydraulic device 90 for moving the movable mold | type 32 in that way is provided (core back means). Due to the core back of the movable mold 32, foam cells grow inside, and a foamed resin molded product 50 having a porous structure excellent in heat insulation, light weight, shock absorption and the like is molded.

  FIG. 2 is a perspective view showing an example of use of the foamed resin molded product 50 molded by the molding apparatus 10. The foamed resin molded product 50 of the present embodiment is an automotive part, and is a ventilation duct that is assembled to the back surface of the instrument panel that is the counterpart member 60. The foamed resin molded product 50 has an opening 51 provided in the molded product 50 separately from the outer periphery 50x. Then, the opening 51 is used to be fitted and assembled to the clip claw 61 of the mating member 60.

  3A and 3B are enlarged cross-sectional views of the main part of the mold according to the first embodiment of the present invention, in which FIG. 3A shows a filling process and FIG. 3B shows a core back process.

  First, with reference to FIG. 7, the problem which arises when the foamed resin molded product 50 is generally molded by core-backing the mold in the past will be described.

  As shown in FIG. 7 (a), in order to form the opening 51 of the foamed resin molded product 50, a concave portion 31 a is formed at a predetermined portion of the cavity forming surface of the fixed mold 31, and the cavity forming surface of the movable mold 32 is formed. A convex portion 32a is formed at the corresponding portion, and the convex portion 32a enters the concave portion 31a. Then, the foamable resin 40 is filled into the cavity 33 formed by the fixed mold 31 and the movable mold 32 in the mold-clamping state (filling step).

  Thereafter, as shown in FIG. 7B, the movable mold 32 is core-backed in the direction in which the volume of the cavity 33 increases, more specifically in the direction in which the thickness of the molded product 50 increases (core-back step). As a result, the shape when viewed from the core back direction (vertical direction in the example) maintains the cavity shape, and the shape when viewed from the direction orthogonal to the core back direction (for example, the horizontal direction in the example) (ie A foamed resin molded product 50 having a thickness that is several times larger than that before the core back is obtained.

  The foamed resin molded product 50 has a structure in which the surface layer portion 50a in contact with the cavity forming surfaces of the fixed mold 31 and the movable mold 32 covers the foamed interior 50b in which the foamed cells are grown. In particular, in the illustrated example, the resin portion in contact with the side surface (vertical surface) of the convex portion 32 a of the movable mold 32 forms the end surface of the peripheral portion of the opening 51.

  However, in reality, when the core back is started or during the core back, the surface layer portion 50a in contact with the cavity forming surface is cooled, the extensibility is lowered, and it is difficult to expand even when subjected to the foaming pressure from the foaming interior 50b. It is in a state. As a result, as shown in FIG. 7C, the surface layer portion 50a does not sufficiently follow the cavity 33 whose volume increases with the core back, and the pressure receiving area of the foaming pressure from the foaming interior 50b is relatively small. In other words, the end surface of the peripheral portion of the opening 51 constituting the thickness of the molded product 50 moves so as to be drawn inward of the molded product 50 when the core is backed.

  As a result, a gap is generated between the end surface of the peripheral edge of the opening 51 and the side surface (vertical surface) of the convex portion 32a of the movable mold 32, and the size of the opening 51 is indicated by a chain line in FIG. Is larger than the target size (indicated by a solid line), and the clip claw 61 is detached from the opening 51 even if the molded product 50 is assembled to the mating member 60 using the opening 51. It happens.

  The example shown in FIG. 7 shows a case where the peripheral edge of the opening 51 is degenerated, but the same problem is caused by the other edge of the planar shape of the foamed resin molded product 50, for example, the edge of the outer periphery 50 x of the molded product 50. This also occurs at the edge portion of the cutout 52 (see FIG. 8B) partially provided on the outer periphery 50x of the molded part 50. As a result, when the edge of the outer periphery 50x is degenerated, the overall size of the molded product 50 in the planar shape becomes smaller than the target size. Further, when the edge of the notch 52 is degenerated, the size of the notch 52 becomes larger than the target size (shown by a solid line) as shown by a chain line in FIG.

  FIG. 9 is a perspective view showing another example of use of the foamed resin molded product 50 different from FIG. In this case, the foamed resin molded product 50 has a notch 52 partially provided on the outer periphery 50x. Then, the cutout 52 is used to fit and position the fitting projection 62 of the mating member 60. However, when the size of the notch 52 becomes larger than the target size as described above, the molded product 50 is fitted to the mating member 60 using the notch 52 and the fitting is attempted. This causes a problem that the protrusion 62 is detached from the notch 52 or is loose.

  Therefore, in this embodiment, the foamed resin molded product 50 illustrated in FIG. 7B, that is, an ideal foamed resin molded product in which the planar shape maintains the cavity shape and the size of the opening 51 is the target size. In order to obtain 50, the shape of the cavity 33 is changed from the shape of the cavity 33 of FIG. 7A as shown in FIG. Specifically, as compared with the cavity 33 in FIG. 7A, the concave portion 31a of the fixed die 31 and the convex portion 32a of the movable die 32 for forming the opening 51 are made smaller in a planar shape.

  As a result, the cavity 33 in FIG. 3A is formed in the main space 33a formed up to the position (target position) of the edge of the molded product 50 when the molded resin molded product 50 is viewed from the core back direction. And a sub space 33b extending from the target position to the outside of the molded product 50 by a predetermined amount continuously with the main space 33a.

  Therefore, in the filling process, if the foamable resin 40 is filled into the cavity 33 in FIG. 3A, the foamable resin 40 exceeds the target position from the main space 33a side to the subspace 33b side by a predetermined amount. The main space 33a and the sub space 33b are filled.

  In particular, in the first embodiment, the side surface (vertical surface) at the top of the convex portion 32a of the movable mold 32 is not parallel to the core back direction, but is inclined toward the main space 33a toward the upper side.

  Here, the “predetermined amount” in which the sub space 33b of the cavity 33 is extended may be increased or decreased according to the core back distance. For example, the longer the core back distance, the larger.

  In the first embodiment, as shown in FIG. 3A, hot water passages 31b and 32b (resin temperature setting means) are provided inside the fixed mold 31 and inside the movable mold 32. In this case, in the fixed mold 31, the hot water passage 31b passes only in the vicinity of the sub space 33b, and in the movable mold 32, the hot water passage 32b is provided so as to expand in volume in the vicinity of the sub space 33b.

  Accordingly, by passing warm water through the warm water passages 31b and 32b, the temperature of the portion of the fixed mold 31 that forms the sub space 33b of the cavity 33 and the temperature of the portion of the movable mold 32 of the fixed mold 31 that forms the main space 33a. The temperature of the part and the temperature of the part of the movable mold 32 become higher, and thereby the temperature of the foamable resin 40 in the sub space 33b of the cavity 33 (the part designated as “warming target part” in the drawing) is set in the main space 33a. The temperature of the expandable resin 40 can be made higher.

  In other words, by passing the hot water through the hot water passages 31b and 32b, the sub-foaming resin 40 filled beyond the target position is in contact with the cavity forming surface of the fixed mold 31 and the cavity forming surface of the movable mold 32. The temperature of the cavity forming surface of the space 33b is higher than the temperature of the cavity forming surface of the main space 33a, so that the expandable resin 40 filled in the cavity 33 is filled in the sub space 33b filled beyond the target position. The temperature of the foamable resin 40 (the portion designated as “warming target portion” in the figure) can be made higher than the temperature of the foamable resin 40 in the main space 33a.

  In this case, the supply of warm water to the warm water passages 31b and 32b, that is, the warming of the region to be warmed is performed during the core back. Preferably, the supply of hot water is started before the start of core back, and the supply of hot water is ended before the end of core back. Here, the longer the end time of the hot water supply with respect to the end time of the core back, the longer the cooling time of the foamed resin molded product 50 before mold opening, and the lower the productivity. And determine the supply time of hot water.

  Instead of warm water, other fluids such as steam may be passed.

  Moreover, you may make it let warm water pass only to the fixed mold | type 31 or the movable mold | type 32 only.

  As described above, in the present embodiment, when the movable mold 32 is core-backed and the foamed resin molded product 50 is molded, when the molten foamable resin 40 is filled, the edge ( The foamed resin molded product 50 after molding was viewed from the core back direction in consideration of degeneration of the outer periphery 50x, the edge of the opening 51, the edge of the opening 51, the edge of the notch 52, or the like into the molded product 50. Since the position of the edge (target position) of the molded product 50 at a time exceeds the outside of the molded product 50 by a predetermined amount, the foamable resin 40 is filled into the cavity 33. In other words, the target position Since the foamable resin 40 is filled into the main space 33a and the subspace 33b from the main space 33a side to the subspace 33b side by a predetermined amount, the foam filled in the cavity 33 is started at the start of the core back. Resin 4 The foamable resin 40 in the sub-space 33b which will form the edges of the molded article 50 of the will be present outside of the molded article 50 than the target position.

  When the core back is performed in this state, as shown in FIG. 3 (b), the edge of the molded product 50 is retracted inward of the molded product 50. The problem of the defective shape of the foamed resin molded product 50 due to the degeneration or the problem of the decrease in dimensional accuracy in the planar shape is suppressed.

  Preferably, the amount of the foamable resin 40 to be filled beyond the target position, in other words, the sub space 33b so that the position of the edge of the actually obtained foamed resin molded product 50 coincides with the target position. Is previously determined experimentally.

  Here, in the first embodiment, as described above, the shape of the side surface (vertical surface) at the upper part of the convex portion 32a of the movable mold 32 is not parallel to the core back direction, but closer to the main space 33a as it is upward. As a result, the end surface of the edge of the degenerated molded product 50 (the end surface of the edge of the outer periphery 50x constituting the thickness of the molded product 50, the end surface of the peripheral portion of the opening 51, or the notch 52 is thereby formed. The shape of the edge of the edge portion of the film is relatively flat (see FIG. 3B and FIG. 7C for comparison).

  In the present embodiment, the core in a state where the temperature of the foamable resin 40 in the sub space 33b filled in the cavity 33 beyond the target position is higher than the temperature of the foamable resin 40 filled in the main space 33a. Since it is made to back, the expansion | extension fall of the surface layer part 50a of the foamable resin 40 in the subspace 33b which will form the edge of the molded article 50 is suppressed, and the degeneracy degree of the edge of the molded article 50 Becomes smaller. Accordingly, it is possible to reduce the amount of the foamable resin 40 that fills the sub space 33b beyond the target position, and the problem of poor shape of the foamed resin molded product 50 or the problem of reduced dimensional accuracy in the planar shape is more likely. It will be further suppressed.

  In that case, for example, by simply increasing the temperature of the cavity forming surface of the fixed mold 31 or the movable mold 32 without inserting a heating device or the like directly into the foamable resin 40 filled in the cavity 33, The temperature of the foamable resin 40 (warming target part) filled in the sub space 33b beyond the target position can be surely made higher than the temperature of the foamable resin 40 filled in the main space 33a.

  And the problem of the shape defect that the size of the opening 51 provided in the molded product 50 and the size of the notch 52 provided on the outer periphery of the molded product 50 is larger than the target size is reduced. A foamed resin molded product 50 having a high dimensional accuracy in the planar shape of the opening 51 and the notch 52 is obtained. The fitting of the molded product 50 and the mating member 60 using the opening 51 and the notch 52 are obtained. Thus, the fitting and positioning of the molded product 50 and the mating member 60 can be performed satisfactorily.

  Furthermore, since the foamable resin 40 in the melted state filling the cavity 33 is prepared by mixing the physical foaming agent with the base resin in the melted state, for example, the foaming ratio is higher than that of the chemical foaming agent or the like. While the core back distance is long and the edge of the molded product 50 is more likely to be degenerated, there is a problem of shape failure of the foamed resin molded product 50 due to the degeneration or a problem of dimensional accuracy reduction in the planar shape. It will be suppressed. In addition, for example, the foamed cell diameter inside the foamed resin molded product 50 can be made smaller than that of a chemical foaming agent, and the physical properties such as rigidity of the foamed resin molded product 50 can be improved. It becomes.

  In particular, in this embodiment, since the fluid in the supercritical state is mixed with the base resin as the physical foaming agent, the expansion ratio is higher, the core back distance is longer, and the edge of the molded product 50 is degenerated. However, the problem of the shape defect of the foamed resin molded product 50 due to the degeneration or the problem of the decrease in dimensional accuracy in the planar shape is suppressed. In addition, the foamed cell diameter inside the foamed resin molded product 50 can be made even finer, and the physical properties such as rigidity of the foamed resin molded product 50 can be further improved.

  FIG. 4 is an enlarged cross-sectional view of a main part of a molding die according to the second embodiment of the present invention, and shows a filling step similar to FIG.

  The difference from the first embodiment is that, as a resin temperature setting means, instead of the hot water passages 31b and 32b, cartridge heaters 31c and 32c are provided in the vicinity of the sub space 33b of the cavity 33 in the fixed mold 31 and / or the movable mold 32. It is an embedded point. Other configurations are substantially the same as those of the first embodiment. In the second embodiment, the same operation as in the first embodiment is obtained.

  Next, FIG. 5 is an enlarged cross-sectional view of a main part of a mold according to the third embodiment of the present invention, where (a) shows a filling process and (b) shows a core back process. is there.

  The difference from the first embodiment is that the shape of the side surface (vertical surface) at the top of the convex portion 32a of the movable mold 32 is a stepped shape. Also by this, the end face of the edge part of the degenerated molded product 50 (the end face of the edge part of the outer periphery 50x constituting the thickness of the molded product 50, the end face of the peripheral part of the opening 51, or the end face of the edge part of the notch 52). Becomes a relatively flat shape. Other configurations are substantially the same as those of the first embodiment. In the third embodiment, the same operation as that of the first embodiment can be obtained.

  FIG. 6 is an enlarged cross-sectional view of an essential part of a mold according to the fourth embodiment of the present invention, and shows a filling process similar to FIG.

  The difference from the third embodiment is that, as a resin temperature setting means, instead of the hot water passages 31b and 32b, cartridge heaters 31c and 32c are provided in the vicinity of the sub space 33b of the cavity 33 in the fixed mold 31 and / or the movable mold 32. It is an embedded point. Other configurations are substantially the same as those of the third embodiment. In the fourth embodiment, the same operation as in the third embodiment is obtained.

  In addition, although the example shown in FIGS. 3-6 showed especially the periphery of the recessed part 31a and the convex part 32a for forming the opening 51 of the molded article 50, the outer periphery 50x and the notch 52 of the molded article 50 are formed. The same applies to the case.

  In the above, the core back may be performed by moving the fixed mold 31 instead of the movable mold 32 or by moving both the movable mold 32 and the fixed mold 31.

  Alternatively, the fixed die 31 may be provided with a convex portion, and the movable die 32 may be provided with a concave portion.

  As described above in detail with reference to specific examples, the present invention, when filling the mold cavity to the foamed resin in the molten state, and then molding the foamed resin molded product by core-backing the mold, As the cavity of the mold, a main space formed up to the position (target position) of the edge of the molded product when the foamed resin molded product after molding is viewed from the core back direction, and the main space is continuous with the main space. Using a cavity having a subspace extending a predetermined amount from the target position to the outside of the molded product, and filling the foamable resin with the foamable resin when filling the foamable resin, the target Molding that occurs when a foamed resin is filled into the main space and the subspace with the position exceeding a predetermined amount from the main space side to the subspace side, thereby forming a foamed resin molded product by core-backing the mold. To the inside of the molded product at the edge Because this technology can suppress the problem of poor shape of foamed resin molded products and the problem of reduced dimensional accuracy in flat shape caused by shrinkage, it can be used in a wide range of industrial applications in the field of resin molding. Potential is expected.

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 best embodiment of this invention, Comprising: (a) shows a filling process, (b) shows a core back process. It is a perspective view which shows the usage example of the foamed resin molded product shape | molded with the said shaping | molding apparatus. It is a principal part expanded sectional view of the shaping | molding die concerning the 1st Embodiment of this invention, Comprising: (a) shows a filling process, (b) shows a core back process. FIG. 4 is an enlarged cross-sectional view of a main part of a molding die according to a second embodiment of the present invention, and shows a filling step similar to FIG. It is a principal part cross-sectional enlarged view of the shaping | molding die concerning the 3rd Embodiment of this invention, Comprising: (a) shows a filling process, (b) shows a core back process. FIG. 10 is an enlarged cross-sectional view of a main part of a mold according to a fourth embodiment of the present invention, and shows a filling step similar to FIG. It is a principal part expanded sectional view which shows the shaping | molding operation | movement of a conventional general foamed resin molded product, Comprising: (a) shows a filling process, (b) shows an ideal core back process, (c) is reality This shows the core back step. It is a top view which shows (a) opening and (b) notch of the foamed resin molded product obtained as a result of the actual core back process of FIG.7 (c). It is a perspective view which shows another example of use of the foamed resin molded product shape | molded with the said shaping | molding apparatus similarly to FIG.

Explanation of symbols

10 Molding device 20 Injection machine (filling means)
24 Supercritical fluid supply nozzle (foaming agent supply means)
30 Mold 31b, 32b Hot water passage (resin temperature setting means)
31c, 32c heater (resin temperature setting means)
33 Cavity 33a Main space 33b Subspace 40 Foamable resin 50 Foamed resin molded product 50x Outer periphery 51 Opening 52 Notch 90 Hydraulic device (core back means)

Claims (10)

A method of molding a foamed resin molded product in which a mold mold cavity is filled with a foamed resin in a molten state, and then the mold is core-backed.
As the cavity, a main space formed up to the position of the edge of the molded resin molded product when viewed from the core back direction, and the outside of the molded product from the position continuously to the main space. Using a sub-space extending a predetermined amount on the side,
When filling the foamable resin, the position of the cavity exceeds a predetermined amount from the main space side to the subspace side, and the main space and the subspace of the cavity are filled with the foamable resin ,
During the core back of the mold, the temperature of the foamable resin filled in the subspace among the foamable resin filled in the cavity of the mold is set higher than the temperature of the foamable resin filled in the main space. Molding method for foamed resin molded products. A method for molding a foamed resin molded article according to claim 1,
Foaming that fills the main space with the temperature of the expandable resin filled in the subspace by making the temperature of the cavity forming surface of the subspace out of the cavity forming surface of the mold higher than the temperature of the cavity forming surface of the main space A method for molding a foamed resin molded product, characterized in that the temperature is higher than the temperature of the functional resin . A method for molding a foamed resin molded product according to claim 1 or 2 ,
The method of molding a foamed resin molded product, wherein the edge is an edge of a notch provided on the outer periphery of the molded product and / or a peripheral edge of an opening provided in the molded product. A method for molding a foamed resin molded article according to any one of claims 1 to 3,
A method for molding a foamed resin molded article, comprising producing a foamable resin in a molten state by mixing a physical foaming agent with a base resin in a molten state . A method for molding a foamed resin molded product according to claim 4 ,
A method for molding a foamed resin molded product, wherein a fluid in a supercritical state is used as the physical foaming agent . An apparatus for molding a foamed resin molded article, comprising: filling means for filling a mold cavity with a foamable resin in a molten state; and core back means for core-backing the mold after filling of the foamable resin by the filling means. There,
The cavity includes a main space formed up to a position of an edge of the molded product when the molded resin molded product is viewed from the core back direction, and the outside of the molded product from the position continuously from the main space. And a subspace extending a predetermined amount on the side,
Resin that raises the temperature of the foamable resin filled in the subspace among the foamable resin filled in the cavity of the mold during the coreback by the coreback means higher than the temperature of the foamable resin filled in the main space. A molding apparatus for a foamed resin molded product, comprising temperature setting means . A molding apparatus for a foamed resin molded product according to claim 6,
The resin temperature setting means is for making the temperature of the cavity forming surface of the sub space out of the cavity forming surface of the mold higher than the temperature of the cavity forming surface of the main space . Molding equipment. A molding apparatus for a foamed resin molded product according to claim 6 or 7 ,
The molding apparatus for a foamed resin molded product, wherein the edge is an edge of a notch provided on the outer periphery of the molded product and / or a peripheral edge of an opening provided in the molded product. A molding apparatus for a foamed resin molded product according to any one of claims 6 to 8 ,
An apparatus for molding a foamed resin molded article, comprising foaming agent supply means for mixing a physical foaming agent with a base resin in a molten state in order to produce the foamable resin in a molten state . A molding apparatus for a foamed resin molded product according to claim 9 ,
The foaming resin supply unit is characterized by mixing a fluid in a supercritical state as the physical foaming agent .

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