JP5757200B2 - Molding method and molding apparatus using core - Google Patents

Description

  The present invention relates to a molding method and a molding apparatus using a core. More specifically, the present invention relates to a hollow molded product having an opening, and the inner diameter of the opening can be regulated with high accuracy and has a desired size. The present invention relates to a molding method and a molding apparatus using a core capable of realizing a hollow portion.

Conventionally, resin hollow molded articles having openings have been used in many applications such as curved pipes, solar water heater collectors, and automobile parts.
For example, Patent Documents 1 to 3 each disclose a method and apparatus for forming a hollow molded product having such an opening.

According to Patent Document 1, a lumbar support for an automobile part having a tubular portion communicating with a hollow portion around a flat hollow body and having a pipe joint inserted into the tubular portion is disclosed. A technique of blow molding using a core is disclosed for forming such an opening for insertion based on two plastic sheets.
More specifically, using a core that regulates the inner diameter of the tubular portion, two molten resin sheets are disposed between the split molds, and the tubular portion is to be molded between the two molten resin sheets. The core is placed on the mold, the divided mold is clamped, and blow molding is performed to weld the outer peripheral parts of the two molten resin sheets to form a hollow part inside and mold the tubular part. Finally, the split mold is opened and the core is pulled out to form the lumbar support.

According to Patent Document 2, a collector of a solar water heater having a plurality of tubular portions each extending in the width direction and connected to each other at a side edge portion is disclosed. As a method for manufacturing this collector, two plastic sheets are used. Based on this, a technique for blow molding using a core is disclosed.
More specifically, a frame-shaped intermediate mold that can be disassembled is provided between a pair of split molds each having a sliding mold arranged around the cavity, and the relative movement direction of the pair of split molds A plurality of cores are provided in the hollow portion of the intermediate mold in a direction substantially orthogonal to the two molds, and two molten resin sheets are arranged with the intermediate mold sandwiched between the divided molds, and between the two molten resin sheets. By placing a core that regulates the inner diameter of the tubular part at the position where the tubular part is to be molded, and before clamping the split mold, each sliding mold is moved to the opposite surface of the intermediate mold. The corresponding molten resin sheet is sandwiched between the sliding mold and the intermediate mold to prevent the two molten resin sheets from coming into contact with each other during molding, and then separating the mold By tightening and performing blow molding, the tubular part is formed by two molten resin sheets, Later, the intermediate mold to decompose moved, together with the mold is opened split mold, drawing the core, so that removing the molded article from the intermediate mold.

According to Patent Document 3, for a hollow molded article having an opening, a mouth-molding male mold is inserted between a pair of sheets extruded by an extruder, and the mouth-molding female mold is closed to open the mouth. The mouth molding die air is formed with the blow molding die closed while the inner molding portion and the outer diameter portion of the opening of the hollow molding product are molded with the male molding die and the female molding die. The point which shape | molds the main-body part of a hollow molded article by injecting air from a blowing inlet is disclosed.
According to these molding methods and molding apparatuses, as in the case of a blow molding method using an ordinary parison, the irregularities that occur if the inner peripheral surface of the tubular portion is formed by blowing pressure is a core that regulates the inner diameter of the tubular portion. Although it is possible to reduce the risk of air leakage when a pipe joint is inserted into the tubular part and communicated with the hollow part, for example, the following techniques Problems exist.

First, it is difficult to pull out the core itself, and if it is pulled out forcibly, the inner peripheral surface of the tubular portion regulated by the core is roughened, and it is difficult to form a highly accurate inner diameter.
More specifically, when the mold of the divided mold is clamped, the outer peripheral surface of the core is pressed against the inner surface of each of the two molten resin sheets. When the mold of the divided mold is opened, the two molten resin sheets Between each of the corresponding mold dies, the mold opening direction (horizontal direction) of the mold dies and the irregularities formed on the inner surfaces of the two molten resin sheets have a low degree of intersection. On the other hand, the drawing direction of the core has a high degree of intersection with the irregularities formed on the inner surfaces of the two molten resin sheets, and accordingly, when the core is drawn, each of the two molten resin sheets and the core The resin sheet is likely to stick to the outer peripheral surface, and the resin sheet is in a molten state, making it difficult to pull out.

Secondly, if the inner diameter and the outer diameter of the opening are simultaneously formed by clamping the mold, it is difficult to ensure the accuracy of the inner diameter.
More specifically, during mold clamping of the split mold, each of the two molten resin sheets is compressed between the corresponding cavity and the outer surface of the core, and the inner diameter and outer diameter of the opening are simultaneously applied. Since the molten resin sheet is not fixed to the core and the mold, due to the compression accompanying the mold clamping, a deviation occurs between the mold or the core and the molten resin sheet. The inner diameter of the opening may not be accurately regulated.

Third, when the split mold is opened, the formed hollow portion expands, and it becomes difficult to form a hollow portion having a desired volume.
More specifically, since molding is performed by applying blowing pressure from the sealed space formed by clamping the molds of the split mold, the pressing force directed from the outer peripheral surface of the molded product to the inside is released when the mold is opened. The formed hollow part will expand. In this respect, it is difficult from the first point to complete the extraction of the core before the mold opening to make the outside air communicate with the hollow portion.

Fourth, in order to prevent the two resin sheets from being welded due to mold clamping, it is necessary to prepare an intermediate mold that can be disassembled, which causes an increase in size and complexity of the molding apparatus.
More specifically, as disclosed in Patent Document 2, it is necessary to prepare a decomposable intermediate mold and a sliding mold that hold two resin sheets apart from each other. And complexity.

These technical problems are, in particular, a molded article having a tubular part having one end communicating with the sealed hollow part and the other end opening outwardly on the outer periphery of the molded article having the sealed hollow part. This is a problem that closes up when connected to the external pipe joint in a liquid seal form through the end opening.
No. 4-7893 JP 61-228930 JP-A-6-190907

In view of the above technical problems, an object of the present invention is a hollow molded product having an opening, and the inside diameter of the opening can be regulated with high accuracy, and a hollow part having a desired size can be realized. Another object is to provide a molding method and a molding apparatus using a core.
In view of the above technical problems, the object of the present invention is good when avoiding complication and enlargement of the molding apparatus when molding a hollow molded product having an opening using two molten resin sheets. An object of the present invention is to provide a molding apparatus using a core that can ensure a good moldability.

In order to achieve the above object, a molding method using the core of the present invention is:
A method for forming a hollow molded article having an opening,
A core having an outer shape complementary to the inner diameter of the opening and coated on the outer surface with a coating that is non-adhesive to the thermoplastic resin, and cavities surrounded by pinch-off portions are arranged opposite to each other, and are clamped A pair of split molds that are movable relative to each other between a position and a mold opening position, and each split mold cavity is provided with a recess that is complementary to the outer diameter of the opening. And the stage of preparing
The two thermoplastic resin sheets are spaced apart from each other and are disposed between the pair of split molds at the mold opening position in a form that protrudes from the cavity, and the opening to be formed in the thermoplastic resin sheet Depending on the position and orientation of the, in a form protruding inward from the pinch-off portion, the core is disposed between two thermoplastic resin sheets,
A sealed space is formed between at least one of the thermoplastic resin sheets and the corresponding molds of the pair of molds, and one of the thermoplastic resin sheets is sucked by decompressing air from the sealed space. And regulating the outer diameter of the opening by shaping along the corresponding cavity;
By moving the pair of split molds to the clamping position, two thermoplastic resin sheets are welded to form a hollow portion inside, and each of the two thermoplastic resin sheets can be handled. Regulating the inner diameter of the opening by sandwiching between the cavity and the outer shape of the core;
Opening the pair of split molds to a mold opening position and pulling the core from the formed opening in a direction intersecting the relative movement direction of the pair of split molds.

According to the molding method using the core having the above configuration, the outer diameter of the opening is regulated by sucking at least one of the two thermoplastic resin sheets and shaping the sheet along the corresponding cavity. Then, by moving the pair of split molds to the clamping position, two thermoplastic resin sheets are welded to form a hollow portion inside, and two thermoplastic resin products By restricting the inner diameter of the opening by sandwiching each sheet between the corresponding cavity and the outer shape of the core, the inner diameter of the opening is controlled by clamping a pair of split molds as in the past. Compared to the case where the outer diameter is regulated at the same time, the outer diameter of the opening is first regulated, and the inner diameter of the opening is thus reduced in a state where the thermoplastic resin sheet is shaped by vacuum suction with respect to the cavity. Regulation This makes it possible to regulate the inner diameter of the opening while preventing the mold or the core and the thermoplastic resin sheet from being displaced due to compression accompanying the mold clamping, and is non-adhesive to the thermoplastic resin. When the core is pulled out in the direction crossing the relative movement direction of the pair of split molds by regulating the inner diameter of the opening by using the core having the coating on the outer surface, as in the past, the core The melted thermoplastic resin sticks to the outer surface of the glass so that the inner surface of the restricted opening can be smoothly pulled out without roughening, and the inner diameter of the opening can generally be regulated with high accuracy. It is. Furthermore, by forming only by suction without applying the blowing pressure, the molded hollow portion expands when the mold is opened as in the case of molding by the conventional blowing pressure alone, and the desired volume is increased. It is possible to avoid a situation in which it is difficult to mold the hollow portion.

In order to achieve the above object, a molding method using the core of the present invention is:
A method for forming a hollow molded article having an opening,
A core having an outer shape complementary to the inner diameter of the opening and coated on the outer surface with a coating that is non-adhesive to the thermoplastic resin, and cavities surrounded by pinch-off portions are arranged opposite to each other, and are clamped A pair of split molds that are movable relative to each other between a position and a mold opening position, and each split mold cavity is provided with a recess that is complementary to the outer diameter of the opening. And the stage of preparing
Two thermoplastic resin sheets are arranged between a pair of split molds at the mold opening position in such a manner that they are spaced from each other and protrude from the cavity, and at least one thermoplastic resin sheet and a pair of molds Forming a sealed space between the corresponding molds of the mold and reducing the air pressure from the sealed space, sucking one thermoplastic resin sheet and shaping it along the corresponding cavity To regulate the outer diameter of the opening,
In the thermoplastic resin sheet, depending on the position and orientation of the opening to be formed, the core is disposed between the two thermoplastic resin sheets in a form protruding inward from the pinch-off portion;
By moving the pair of split molds to the clamping position, two thermoplastic resin sheets are welded to form a hollow portion inside, and each of the two thermoplastic resin sheets can be handled. Regulating the inner diameter of the opening by sandwiching between the cavity and the outer shape of the core;
Opening the pair of split molds to a mold opening position and pulling the core from the formed opening in a direction intersecting the relative movement direction of the pair of split molds.

The molded product may be a molded product having a tubular portion having one end communicating with the sealed hollow portion and the other end opening outwardly on the outer peripheral portion of the molded product having the sealed hollow portion.
Further, the core is made of iron, and the coating is preferably performed by an electroless composite plating method in which polytetrafluoroethylene fine particles are co-deposited in a nickel-phosphorus film.
Furthermore, the core has a rod-like shape having a communication hole extending in the longitudinal direction and having an end opening provided at the distal end portion. Has an enlarged diameter cut-off part adjacent to the direction,
The core is made of a thermoplastic resin around the boundary between the opening and the hollow portion regulated by the inner diameter regulating portion by ejecting air from the end opening with the core projecting inward from the pinch-off portion. In addition to shaping the sheet, it is preferable that when the pair of split molds are clamped, a step of pushing the boundary between the lip portion and the burr portion of the opening by the enlarged diameter push-cut portion is preferable.

In order to achieve the above object, a molding apparatus using the core of the present invention,
A molding apparatus for molding a hollow molded article having an opening using two thermoplastic resin sheets,
Each of the cavities surrounded by the pinch-off portions is opposed to each other, and is a pair of split molds that can move relative to each other between the clamping position and the mold opening position. A pair of split molds provided with recesses for regulating the outer diameter;
The core is movable between a holding position retracted outward from the pinch-off part and a protruding position protruding inward from the pinch-off part in a direction intersecting the relative movement direction of the pair of split molds. A core for regulating the inner diameter of the opening by the outer surface,
Suction for sucking the corresponding sheets of the two thermoplastic resin sheets disposed at a distance from each other between the pair of split molds provided in at least one of the split molds through the cavity An apparatus,
When each of the two thermoplastic resin sheets is compressed between the core and the corresponding cavity by moving the pair of split molds to the clamping position while the core is in the protruding position. The outer surface of the core is coated with a non-adhesive coating on the thermoplastic resin sheet so that the core can be smoothly pulled out toward the holding position.

    According to the molding apparatus having the above-described configuration, by clamping at least one of the two thermoplastic resin sheets through a corresponding cavity before clamping the pair of split molds, As described above, in order to prevent molding failure due to the two thermoplastic resin sheets sticking to each other when the mold is clamped, each of the pair of split molds is provided with a sliding mold and a pair of split molds. Without providing an intermediate mold that can be disassembled and moved between them, while avoiding complication and enlargement of the molding apparatus, it is possible to ensure good moldability and exhibit non-adhesiveness to the thermoplastic resin. When the core is pulled out in the direction intersecting the relative movement direction of the pair of split molds by regulating the inner diameter of the opening using the core with the coating on the outer surface, the outer surface of the core as in the past Molten thermoplastic By fat Hebaritsuku without the inner surface of the openings regulated is roughened, it is smoothly can pull, it is possible to restrict the inner diameter of the opening with high precision.

The core is made of iron, and the coating is preferably performed by an electroless composite plating method in which polytetrafluoroethylene fine particles are co-deposited in a nickel-phosphorus film.
Furthermore, a first urging means for urging the core toward one mold of the pair of split molds, and a first urging means for biasing the core toward the other mold of the pair of split molds. 2 urging means, and the core is in a balance position between the urging force by the first urging means and the urging force by the second urging means in the relative movement direction of the pair of split molds. It should be positioned.
In addition, the core has a rod-like shape having a communication hole extending in the longitudinal direction with an end opening provided at the distal end portion. Has an enlarged diameter cut-off part adjacent to the direction,
In each of the cavities of the pair of split molds, a second recess that is deeper than the recess having a shape complementary to the opening is preferably provided outside the recess adjacent to the enlarged diameter cut-out portion of the core at the protruding position.

In the following, as a hollow molded article having an opening, a molding method and a molding apparatus will be described in detail below with reference to the drawings, taking as an example a heat collector of a heat collecting hot water apparatus.
As shown in FIGS. 1 and 9, the resin collector panel 200 of the heat collecting and hot water apparatus is an integrally molded product made of resin, and is a panel-shaped 2 in which two resin sheets 216 and 218 are bonded together. The internal flow path 202 is formed inside by forming a layer structure and surface-welding the inner surface 224 of the first resin sheet 216 and the inner surface 226 of the second resin sheet 218. The internal flow path 202 is formed so as to meander in the surface of the resin heat collector panel 200, and is formed over the entire resin heat collector panel 200. The diameter of the internal flow path 202 and the length of the flow path may be determined in relation to the heat collection function required for the heat collector.

More specifically, as will be described later, a meandering first concave groove 232 having a semicircular cross section is formed on the inner surface 224 of the first resin sheet 216 in a manner extending to the edge of the panel. On the inner surface 226 of the resin sheet 218, a meandering second concave groove 234 having the same diameter and a semicircular cross section is formed so as to extend to the edge of the panel, and the inner surface 224 of the first resin sheet 216 and the second surface 226 The internal flow path 202 is formed by bonding to the inner surface 226 of the resin sheet 218. Thus, the internal flow path 202 is formed in a form protruding to the outer surface side of each of the first resin sheet 216 and the second resin sheet 218. The upper end opening of the internal flow path 202 constituting the inflow opening 240 is connected to the hot water discharge pipe 236, while the lower end opening of the internal flow path 202 constituting the outflow opening 242 is connected to the water injection pipe 238, The water in the internal flow path of the heat collector supplied by the water injection pipe 238 is heated by solar heat to become hot water and discharged to the hot water discharge pipe 236. Since the inflow opening 240 and the outflow opening 242 are respectively connected to the hot water discharge pipe 236 and the water injection pipe 238 which are external pipes, a liquid seal is necessary from the viewpoint of preventing leakage at the connection section. However, depending on the heat collecting function required for the heat collector, high-precision regulation of the inner diameter of the internal flow path 202 is required as well.
The material of the heat collector is preferably an olefin resin such as polyethylene or polypropylene, or an amorphous resin.

Next, a molding apparatus for the resin heat collector panel 200 will be described below.
As shown in FIG. 2, the molding device 10 of the resin heat collector panel 200 includes an extrusion device 12 and a mold clamping device 14 disposed below the extrusion device 12, and is extruded from the extrusion device 12. The molten thermoplastic resin sheet P is sent to the mold clamping device 14, and the molten thermoplastic resin sheet P is molded by the mold clamping device 14. Here, since the apparatuses for extruding each of the two thermoplastic resins and sending them to the mold clamping device 14 are the same, only one of them will be described, and the other will be given the same reference number for the description. Omitted.

The extruding device 12 is a conventionally known type, and a detailed description thereof is omitted. However, a cylinder 18 provided with a hopper 16, a screw (not shown) provided in the cylinder 18, and a screw are connected to the screw 18. The hydraulic motor 20, an accumulator 22 that communicates with the inside of the cylinder 18, and a plunger 24 provided in the accumulator 22, and a resin pellet introduced from the hopper 16 is screwed into the cylinder 18 by the hydraulic motor 20. The molten resin is melted and kneaded by the rotation of the resin, and the molten resin is transferred to the accumulator chamber 22 and stored in a certain amount. The plunger 24 is driven to feed the molten resin toward the T-die 28 and through the extrusion slit 34 to a predetermined length. A pair of extruded thermoplastic resin sheets P, spaced apart It is sent out downward while being pinched by the roller 30 and is suspended between the divided molds 32. Thereby, as will be described in detail later, the thermoplastic resin sheet P is disposed between the split molds 32 in a state of having a uniform thickness in the vertical direction (extrusion direction).

The extrusion capability of the extrusion device 12 is appropriately selected from the viewpoint of the size of the resin molded product to be molded, the draw-down of the thermoplastic resin sheet P, or the prevention of neck-in occurrence. More specifically, from a practical point of view, the extrusion amount of one shot in intermittent extrusion is preferably 1 to 10 kg, and the extrusion rate of the resin from the extrusion slit 34 is several hundred kg / hour or more, more preferably 700 kg / hour or more. Further, from the viewpoint of preventing the drawdown or neck-in of the thermoplastic resin sheet P, the extrusion process of the thermoplastic resin sheet P is preferably as short as possible, depending on the type of resin, MFR value, and melt tension value. In general, the extrusion process should be completed within 40 seconds, more preferably within 10 to 20 seconds. For this reason, the unit area and the amount of extrusion per unit time from the extrusion slit 34 of the thermoplastic resin are 50 kg / hour cm ² or more, more preferably 150 kg / hour cm ² or more.

By feeding the thermoplastic resin sheet P sandwiched between the pair of rollers 30 by the rotation of the pair of rollers 30 downward, the thermoplastic resin sheet P can be stretched and thinned, and extruded thermoplastic. By adjusting the relationship between the extrusion speed of the resin sheet P and the feeding speed of the thermoplastic resin sheet P by the pair of rollers 30, it is possible to prevent the occurrence of drawdown or neck-in. It is possible to reduce the restrictions on the type, in particular the MFR value and the melt tension value, or the extrusion rate per unit time.
As an alternative to the pair of rollers 30, before placing the thermoplastic resin sheet P between the pair of split molds 3223, for example, a lower portion of the thermoplastic resin sheet P is sandwiched by a known clamper. The wall thickness of the thermoplastic resin sheet P may be adjusted by pulling downward.

As shown in FIG. 2, the extrusion slit 34 provided in the T die 28 is arranged vertically downward, and the thermoplastic resin sheet P extruded from the extrusion slit 34 is vertically suspended from the extrusion slit 34 in the vertical direction. It is sent downwards. The extrusion slit 34 can change the thickness of the thermoplastic resin sheet P by making the interval variable.
On the other hand, the mold clamping device 14 can reciprocate between the holding position and the protruding position in a direction crossing the relative movement direction of the two divided molds 32A and 32B and the pair of divided molds 32A and 32B. Core 300 and a mold driving device for moving the molds 32A and 32B between the open position and the closed position in a direction substantially orthogonal to the supply direction of the molten thermoplastic resin sheet P. .

As shown in FIG. 2, the two divided molds 32A and 32B are arranged with the cavities 116 facing each other, and the cavities 116 are arranged along the substantially vertical direction. The surface of each cavity 116 is provided with an uneven portion according to the outer shape and surface shape of a molded product molded based on the molten thermoplastic resin sheet P.

In each of the two divided molds 32A and 32B, a pinch-off part 118 is formed around the cavity 116. The pinch-off part 118 is formed in an annular shape around the cavity 116, and the opposing molds 32A and 32B are formed. Protrusively toward. As a result, when the two divided molds 32A and 32B are clamped, the tip portions of the respective pinch-off portions 118 come into contact with each other, and the two molten thermoplastic resin sheets P1 and P2 are formed on the periphery thereof. It is welded so that the parting line PL is formed.
The distance between the surfaces of the opposing cavities 116A, B when the tip portions of the pinch-off portion 118 contact each other is at least smaller than the sum of the thickness of the thermoplastic resin sheet P1 and the thickness of the thermoplastic resin sheet P2. Accordingly, when the divided molds 32A and 32B are clamped, the thermoplastic resin sheet P1 and the thermoplastic resin sheet P2 can be surface-welded. Note that the pinch-off portion 118 may be provided in any one of the molds 32A and 32B.

More specifically, on the surface of the cavity 116A of one mold 32A for molding the thermoplastic resin sheet P1, a half portion of the internal flow path 202 is formed on the outer surface 121 of the thermoplastic resin sheet P1. A first concave portion 119A complementary to the first concave groove 232 is provided so as to form the first concave groove 232, and on the surface of the cavity 116B of the other mold 32B for molding the thermoplastic resin sheet P2, A first concave portion 119B complementary to the second concave groove 234 is provided so as to form a second concave groove 234 constituting a half portion of the internal flow path 202 on the outer surface 122 of the thermoplastic resin sheet P2. Each of the first recesses 119A and 119B has a semicircular cross section, and as will be described later, the first recess groove 232 is shaped by sucking and pressing the thermoplastic resin sheet P1 against the cavity 116A. At the same time, the second groove 234 is shaped by sucking and pressing the thermoplastic resin sheet P2 against the cavity 116B, and when the molds 32A and 32B of the divided type are clamped, the first groove 232 and B are aligned to form an internal flow path 202 having a circular cross section.

As shown in FIGS. 3 and 4, the second recess 120AA and the second recess are formed at both ends of the first recess 119A of the split mold 32A to form the inflow opening 240 and the outflow opening 242, respectively. 120AB is provided so as to be connected to the first recess 119A. Similarly, a second recess is formed at each end of the first recess 119B of the split mold 32B to form an inflow opening 240 and an outflow opening 242. 120BA and the second recess 120BB are provided so as to be connected to the first recess 119B.
Here, the structures of the second recess 120BA and the second recess 120BB provided in the split mold 32B are the same as those of the second recess 120AA and the second recess 120AB provided in the split mold 32A, and the inflow opening 240 is formed. The second recess 120AA for forming the outflow opening 242 and the second recess 120AB for forming the outflow opening 242 have the same structure. Therefore, the second recess 120AA for forming the inflow opening 240 will be described below. Other description is omitted.

  The second recess 120AA is provided in the vicinity of the pinch-off portion 118A of the cavity 116A, and as will be described later, the thermoplastic resin sheet P1 is sucked from the split mold 32A through the cavity 116A, and the second recess 120AA is formed. By pressing against the recess 120AA, the thermoplastic resin sheet P1 is shaped to regulate the outer diameter of the inflow opening 240. Further, when the core 300 is in the projecting position, the second recess 120AA is located at a position facing the inner diameter forming portion of the core 300, and as will be described later, when clamping the divided molds 32A and B, A portion of the thermoplastic resin sheet P1 corresponding to the inflow opening 240 whose outer diameter is regulated is sandwiched between the inner diameter forming portion 322 of the core 300 and the second recessed portion 120AA. The inner diameter of the inflow opening 240 is regulated.

In addition, a third recess 121AA is provided at a position corresponding to an enlarged push-off portion 318 of the core 300, which will be described later, so as to be connected in the extending direction of the second recess 120AA, thereby a pair of split molds 32A, At the time of mold clamping of B, the boundary between the rim 325 of the inflow opening 240 and the burr of the thermoplastic resin sheet is pushed out by the enlarged diameter cut-off section 318, and the burr is cut off as post-processing. To make it easier.
Furthermore, a fourth recess 123AA is provided so as to be connected to the third recess 121AA. The fourth recess 123AA is provided outside the split mold 32A. The fourth recess 123AA is deeper than the third recess 121AA and is connected to the third recess 121AA and the fourth recess 121AA. A shoulder 305 is provided between the recess 123AA. As a result, when the pair of split molds 32A and 32B is clamped, the thermoplastic resin sheet P1 wraps around the center surface side of the core 300 at the end surface 327 of the core 300 of the diameter-enlarged push-off portion 318. Thus, the smooth extraction of the core 300 is not hindered.

  The second recess 120, the third recess 121, and the fourth recess 123 are similarly provided on the outflow opening 242 side of the cavity 116A and on the inflow opening 240 and outflow opening 242 side of the cavity 116B. .

As shown in FIG. 3, the outer side of each of the pair of split molds 32A and 32B is fixed to the mold mounting plate 302, and the mold mounting plates 302A and B are respectively formed of the pair of split molds 32A and 32B. On each of the front and rear sides (upper side and lower side in the drawing), they are slidably connected to tie bars 304 extending in parallel to each other. Accordingly, the pair of divided molds 32A and 32B can be moved between the mold clamping position and the mold opening position along the pair of tie bars 304A and B by the mold moving means.

In one tie bar 304, a core 300 for regulating the inner diameters of the inflow opening 240 and the outflow opening 242 by the outer surface is orthogonal to the moving direction of the pair of split molds 32 </ b> A and 32 </ b> B via the base 306. It is attached to extend in the direction. FIG. 3 shows only the regulating core of the inflow opening 240.
The core 300 is positioned in a direction perpendicular to the relative movement direction of the pair of split molds 32A and 32B, for example, by a known piston-cylinder mechanism 308, and a retracted position retracted outward from the pinch-off part 118 and from the pinch-off part 118. It is possible to move between the protruding positions protruding in the direction. The protruding position of the core 300 is determined according to the position and orientation of the inflow opening 240. More specifically, the amount of protrusion that protrudes inward from the pinch-off portion 118 is a pair in the relationship between the second recess 120, the third recess 121, and the fourth recess 123 provided in each of the pair of split molds 32A and 32B. When the divided molds 32A and 32B are clamped, the inner diameter regulating portion 322 of the core 300 faces the second recess 120, and the thermoplastic resin sheet P1 is sandwiched between the second recess 120 and the inner diameter regulating portion 322. Set to be pressed.
In particular, the position of the core 300 in the relative movement direction of the pair of split molds 32A, B is the distance between the outer surface of the core 300 and each of the cavities 116A, B when the pair of split molds 32A, B are clamped. Is set to be smaller than at least the thickness of the thermoplastic resin sheets P1 and P2, so that by clamping the molds, the thermoplastic resin sheets P1 and P2 are respectively connected to the cavities 116A and B and the outer surface of the core 300. It is made to be pinched between.
On the other hand, the reserved position of the core 300 is a position that does not collide with the mold at least when the pair of split molds 32A and 32B is opened.

The tie bar 304 includes a first spring 310 that biases the core 300 toward one mold 32B of the pair of split molds 32A and 32B, and the core 300 that is the other mold of the pair of split molds 32A and B. The second spring 312 urging toward 32A is between the left side surface of the base 306 and the mold mounting plate 302 of the other mold 32A, and the right side surface of the base 306 and the mold of the one mold 32B. Provided between the mold mounting plate 302 and the urging force of the first spring 310 and the urging force of the second spring 312 against the core 300 in opposite directions. As a result, the core 300 is positioned at a balance position between the urging force of the first spring 310 and the urging force of the second spring 312 in the relative movement direction of the pair of split molds 32A and 32B. When the molds 32A and 32B are clamped, for example, when one mold 32A of the split mold 32 hits the outer surface of the core 300 due to a manufacturing error or an installation error, the core 300 is moved by the second spring 312. It is possible to move toward the other mold 32B while resisting the urging force, and the core 300 is prevented from being damaged or broken.

As shown in FIG. 4, the core 300 has a rod shape having a communication hole 316 extending in the longitudinal direction with an end opening 314 provided at the distal end portion. The core 300 is formed with an inner diameter regulating portion 322 on the outer surface of the distal end portion. A diameter-enlarged push-out portion 318 is provided adjacent to the portion 322 in the longitudinal direction outward. Thus, the air 300 is ejected from the end opening 314 in a state where the core 300 is projected inwardly from the pinch-off portion 118, whereby the inflow opening 240 and the hollow portion regulated by the inner diameter regulating portion 322 are discharged. And forming the thermoplastic resin sheet P around the boundary between the pair of split molds 32A and 32B, the lip portion 325 and the burr portion of the inflow opening 240 by the enlarged diameter cut-off portion 318. The boundary is pushed all the way. In addition, what is necessary is just to determine the hole diameter of the communicating hole 316 from such a viewpoint. When clamping the pair of split molds 32A and 32B, the communication hole 316 may be used for the purpose of preventing an increase in internal pressure due to compression.

The inner diameter regulating portion 322 of the core 300 has two thermoplastic resins as will be described later by moving the pair of split molds 32A and 32B to the clamping position with the core 300 in the protruding position. When each of the sheets P1 and P2 is compressed between the core 300 and the corresponding cavity 116, the core 300 is made non-adhesive to the thermoplastic resin sheet P so that the core 300 can be smoothly pulled out toward the standby position. The provided coating is given. More specifically, the core 300 is made of iron, and coating is performed by an electroless composite plating method in which polytetrafluoroethylene fine particles are co-deposited in a nickel-phosphorus film.

PTFE (polytetrafluoroethylene) has a high melting point (327 ° C.), is a chemically extremely inert substance, has a dense and smooth surface, and has a low surface energy. It has a coefficient of 0.02, the lowest coefficient of friction among plastics, and has a so-called self-lubricating property that has a low coefficient of friction even without the use of a lubricant. It has been found that by co-depositing PTFE fine particles in the electroless Ni film, the dynamic friction coefficient of the plating film is reduced, and the dynamic friction coefficient is further reduced when the PTFE content is large. Moreover, as non-adhesiveness, a water contact angle is 114 degrees. Here, the contact angle refers to the angle at which the liquid turns into a solid at the contact line when it is brought into contact with the liquid and its vapor or air containing the vapor (generally other gas may be used). The larger the corner, the less wet and the non-adhesive, so the non-adhesive is also excellent. In particular, when the PTFE content increases, the contact angle tends to increase. The PTFE particle size is preferably 1 μm or less.
Note that the core 300 that forms the outflow opening 242 is the same as the core 300 that forms the inflow opening 240 described above, and a description thereof will be omitted.
Incidentally, in FIG. 5 and the subsequent figures, the equipment around the core 300 including the mold mounting plate 302 is omitted for the sake of clarity.

A mold 33A is slidably fitted on the outer periphery of the mold 32A so as to be slidable in a sealed state, and the mold 33A can be moved relative to the mold 32A by a mold moving device (not shown). . More specifically, the mold frame 33A can be brought into contact with the side surface of the thermoplastic resin sheet P1 disposed between the molds 32A and 32B by projecting toward the mold 32B with respect to the mold 32A. is there. Although omitted in the drawing, similarly, a mold frame 33B is provided on the outer periphery of the mold 32B, and the mold frame 33B protrudes toward the mold 32A with respect to the mold 32B. The thermoplastic resin sheet P2 disposed between the molds 32A and 32B can be brought into contact with the side surface.

The mold driving device is the same as the conventional one, and the description thereof is omitted. However, the two divided molds 32A and 32B are respectively driven by the mold driving device and are divided into two in the open position. Two molten thermoplastic resin sheets P can be arranged between the molds 32A and 32B, and the pinch-off portions 118 of the two divided molds 32A and 32B are in contact with each other in the closed position. The annular pinch-off portions 118 abut against each other. Regarding the movement of the molds 32A, 32B from the open position to the closed position, the closed position, that is, the position where the pinch-off portions 118 are in contact with each other is between the two molten thermoplastic resin sheets P1, P2. The positions are equidistant from both the thermoplastic resin sheets P1 and P2, and the molds 32A and 32B are driven by the mold driving device to move toward the positions.
The extrusion device and the pair of rollers for the thermoplastic resin sheet P1, and the extrusion device and the pair of rollers for the thermoplastic resin sheet P2 are arranged symmetrically with respect to this closed position.

As shown in FIG. 6, a vacuum suction chamber 80 is provided inside the divided mold 32 </ b> A, and the vacuum suction chamber 80 communicates with the cavity 116 </ b> A through the suction hole 82, and the suction hole 82 is opened from the vacuum suction chamber 80. By sucking through, the thermoplastic resin sheet P1 is adsorbed toward the cavity 116A and shaped into a shape along the outer surface of the cavity 116A. More specifically, the first concave groove 232 is formed in the outer surface 121 of the thermoplastic resin sheet P1 by the first concave portion 119A provided on the outer surface of the cavity 116A. Although not shown, the divided mold 32B is similarly provided with a vacuum suction chamber that communicates with the cavity 116B via a suction hole.

The thermoplastic resin sheets P1 and P2 are formed of a sheet formed of an olefin resin such as polyethylene or polypropylene, or an amorphous resin. More specifically, the thermoplastic resin sheets P1 and P2 are preferably made of a resin material having a high melt tension from the viewpoint of preventing the occurrence of thickness variation due to drawdown, neck-in, etc. It is preferable to use a resin material with high fluidity in order to improve transferability to the mold and followability.

More specifically, it is a polyolefin (for example, polypropylene, high density polyethylene) which is a homopolymer or copolymer of an olefin such as ethylene, propylene, butene, isoprene pentene, methyl pentene, etc., and has an MFR (JIS) at 230 ° C. According to K-7210, measured at a test temperature of 230 ° C. and a test load of 2.16 kg) of 3.0 g / 10 min or less, more preferably 0.3 to 1.5 g / 10 min, or acrylonitrile butadiene Amorphous resin such as styrene copolymer, polystyrene, high impact polystyrene (HIPS resin), acrylonitrile / styrene copolymer (AS resin), MFR at 200 ° C. (test temperature 200 according to JIS K-7210) ℃, measured at a test load of 2.16 kg) is 3.0 to 60 g / 10 min More preferably, the melt tension at 30 to 50 g / 10 min and at 230 ° C. (using a melt tension tester manufactured by Toyo Seiki Seisakusho Co., Ltd., preheating temperature 230 ° C., extrusion speed 5.7 mm / min, diameter 2.095 mm) The strand is extruded from an orifice having a length of 8 mm and the tension when the strand is wound around a roller having a diameter of 50 mm at a winding speed of 100 rpm) is 50 mN or more, preferably 120 mN or more. The

A method for manufacturing the resin heat collector panel 200 using the molding apparatus 10 for the resin heat collector panel 200 having the above configuration will be described below with reference to the drawings.

  First, in FIG. 2, a predetermined amount of the melted and kneaded thermoplastic resin is stored in the accumulator 22, and the stored thermoplastic resin is discharged from the extrusion slit 34 provided at a predetermined interval on the T die 28 at a predetermined extrusion amount per unit time. In this case, the thermoplastic resin swells and is extruded at a predetermined extrusion speed with a predetermined thickness so as to hang downward into a molten sheet.

Next, the pair of rollers 30 is moved to the open position, and the gap between the pair of rollers 30 disposed below the extrusion slit 34 is expanded beyond the thickness of the thermoplastic resin sheet P, thereby being extruded in a molten state. The lowermost portion of the thermoplastic resin sheet P is smoothly supplied between the pair of rollers 30. In addition, the timing which makes the space | interval of the rollers 30 wider than the thickness of the sheet P made of thermoplastic resin may be performed not after the start of extrusion but at the end of the secondary molding for each one shot.
Next, the pair of rollers 30 are moved close to each other and moved to the closed position, the interval between the pair of rollers 30 is narrowed to sandwich the thermoplastic resin sheet P, and the thermoplastic resin sheet P is moved downward by the rotation of the rollers. Send it out.

Next, as shown in FIG. 2, the thermoplastic resin sheet P having a uniform thickness in the extrusion direction is disposed between the split molds 32 </ b> A and 32 </ b> B disposed below the pair of rollers 30. Thus, the thermoplastic resin sheet P is positioned in a form that protrudes around the pinch-off portion 118.
The above process is performed for each of the two thermoplastic resin sheets P1 and P2, and between the divided molds 32A and 32B, with the thermoplastic resin sheet P2 and the thermoplastic resin sheet P1 being spaced apart from each other. To place.
In this case, as described above, the two thermoplastic resin sheets P1 and P2 can be divided into separate molds 32A by adjusting the interval between the extrusion slits 34 or the rotational speed of the pair of rollers 30 independently of each other. , B can be adjusted in thickness.
Next, as shown in FIG. 5, the mold 33A is moved relative to the mold 32A toward the thermoplastic resin sheet P1 until it contacts the outer surface 117 of the thermoplastic resin sheet P1 facing the mold 32A. .

Next, as shown in FIG. 6, a first sealed space formed by the cavity 116A of the mold 32A, the inner peripheral surface 102 of the mold 33A, and the outer surface 117 of the thermoplastic resin sheet P1 facing the mold 32A. The thermoplastic resin sheet P1 is pressed against the cavity 116A by suctioning from the vacuum suction chamber 80 through the suction hole 82 through 84, and the thermoplastic resin sheet P1 is formed into a shape along the uneven surface of the cavity 116A. Is shaped. Thus, the thermoplastic resin sheet P1 is shaped so that the first concave groove 232 protrudes to the outer surface 117 side, and a part of the internal flow path 202 is formed in a half shape. At the same time, the thermoplastic resin sheet P1 is pressed against the second recess 120AA of the cavity 116A to restrict the outer diameter of the inflow opening 240, while the thermoplastic resin sheet P1 is pressed to the second recess 120A of the cavity 116A. The outer diameter of the outflow opening 242 is regulated by being pressed against 120AB.
Similarly, with respect to the other thermoplastic resin sheet P2, the thermoplastic resin sheet P2 is pressed against the cavity 116B, and the thermoplastic resin sheet P2 is shaped into a shape along the uneven surface of the cavity 116B. While a part of the internal flow path 202 is formed in a half shape, the thermoplastic resin sheet P2 is pressed against the second recess 120BA of the cavity 116B, and the outer diameter of the inflow opening 240 is restricted. The sheet P2 made of thermoplastic resin is pressed against the second recess 120BB of the cavity 116B, and the outer diameter of the outflow opening 242 is restricted.

Next, as shown in FIG. 7, the thermoplastic resin sheet P1 is sucked and held in a state where the mold 33A contacting the outer surface 117 of the thermoplastic resin sheet P1 is held as it is, and the plastic resin sheet is used. While holding the thermoplastic resin sheet P2 in the same manner while holding the mold 33B that contacts the outer surface 117 of P2 in the same position, a pair of annular pinch-off portions 118A and B are in contact with each other until they contact each other. The divided molds 32A and 32B are moved toward each other and clamped. In this case, the contact position in the mold clamping direction between the pinch-off portions 118A and 118B is between the two thermoplastic resin sheets P1 and P2 that are spaced apart from each other. As shown in FIG. By contacting B with each other, a flat portion other than the first concave groove 232 and a flat portion other than the second concave groove 234 of the thermoplastic resin sheet P2 are formed on the outer surface 121 of the thermoplastic resin sheet P1. The internal flow path 202 is formed by surface welding. At the same time, the inner diameters of the inflow opening 240 and the outflow opening 242 are regulated. More specifically, the portion corresponding to the inflow opening 240 whose outer diameter is regulated in the thermoplastic resin sheet P1 is clamped to the inner diameter regulating portion 322 of the core 300 corresponding to the second recess 120AA of the cavity 116A. On the other hand, the portion of the thermoplastic resin sheet P1 corresponding to the outflow opening 242 whose outer diameter is restricted is the inner diameter of the core 300 corresponding to the second recess 120AB of the cavity 116A by clamping. It is pinched by the restricting portion 322, and the inner diameter is restricted.
Similarly, with respect to the other thermoplastic resin sheet P2, the portion corresponding to the outflow opening 242 of the thermoplastic resin sheet P2 whose outer diameter is regulated is separated from the second recess 120BA of the cavity 116B by clamping. On the other hand, the portion corresponding to the outflow opening 242 of the thermoplastic resin sheet P2 whose outer diameter is restricted is clamped by the corresponding inner diameter restricting portion 322 of the core 300, and the second portion of the cavity 116B is clamped by mold clamping. The concave portion 120BB and the corresponding inner diameter restricting portion 322 of the core 300 are sandwiched and the inner diameter is restricted.
In this case, using the core 300 that regulates the inner diameter of the inflow opening 240, the core 300 protrudes inward from the pinch-off portion 118, and from the end opening 314 of the communication hole 316 provided at the tip of the core 300. It may be preliminarily shaped by jetting air toward the thermoplastic resin sheet P1 or P2 around the boundary between the inflow opening 240 and the hollow part regulated by the inner diameter regulating part 322. In particular, the boundary portion between the inflow opening 240 and the hollow portion is a portion that is not sandwiched between the cavity 116 and the core 300 when the pair of split molds 32A and 32B is clamped. Where the sheet P1 or P2 tends to be thickened due to the sneaking around from the portion where the sheet P1 or P2 is pinched, the thickness may be reduced by directly blowing air to such a thickened portion. The same applies to the core 300 that regulates the inner diameter of the outflow opening 242.
Next, each core 300 is pulled out to the reserved position. In this case, since the outer surface of the core 300 is coated, at the time of drawing, the outer surface of the core 300 sticks to the surfaces of the thermoplastic resin sheets P1 and P2 in a molten state, thereby restricting the inflow opening. The inner surfaces of 240 and the outflow opening 242 can be pulled out smoothly without being roughened, and the inner diameters of the inflow opening 240 and the outflow opening 242 can be regulated with high accuracy.
In addition, by providing the shoulder portion 305 between the third recess portion 121 and the fourth recess portion 123, the core 300 is provided on the end surface 327 on the root portion side of the core 300 of the enlarged diameter cut-off portion 318 when the mold is clamped. So that the core 300 is not obstructed from being smoothly pulled out.

  Next, as shown in FIG. 8, the split molds 32A and B are opened, the molded resin heat collector panel 200 is taken out, and the burr portions B outside the pinch-off portions 118A and B are cut. The molding is completed. At this time, when the pair of split molds 32A and 32B is clamped, the boundary portion between the burr portion and the lip portion 325 of each of the inflow opening 242 and the outflow opening 242 is pushed by the enlarged diameter push-off portion 318. The burr portion B can be easily and efficiently separated.

Next, an external pipe line is connected to each of the inflow opening 240 and the outflow opening 242. Thus, the resin heat collector panel 200 is completed.
As a modification, the step of disposing the core 300 between the two thermoplastic resin sheets is performed even after the step of regulating the outer diameters of the inflow opening 240 and the outflow opening 242 by suction. Good.

As described above, every time the molten thermoplastic resin sheet P is intermittently extruded, the panel-shaped resin heat collector panel 200 can be formed one after another by repeating the above steps. The thermoplastic resin is intermittently extruded as a thermoplastic resin sheet P in a molten state by extrusion molding, and the extruded thermoplastic resin sheet P is applied to a predetermined shape using a mold by vacuum suction molding. It is possible to shape.

According to the molding method using the core 300 having the above-described configuration, by sucking at least one of the two thermoplastic resin sheets P1 and P2 and shaping along the corresponding cavities 116A and B, By restricting the outer diameter of the openings 240 and 242 and then moving the pair of split molds 32A and 32B to the clamping position, the two thermoplastic resin sheets P1 and P2 are welded, A hollow portion is formed inside, and the two thermoplastic resin sheets P1 and P2 are sandwiched between the corresponding cavities 116A and 116B and the outer surface of the core 300, thereby reducing the inner diameter of the openings 240 and 242. By restricting, the pair of divided molds 32A and 32B is clamped as in the prior art, compared with the case where the inner diameter and the outer diameter of the openings 240 and 242 are simultaneously restricted. First, the outer diameters of the openings 240 and 242 are regulated, whereby the inner diameters of the openings 240 and 242 are regulated in a state where the thermoplastic resin sheets P1 and P2 are shaped by vacuum suction with respect to the cavities 116A and B. By doing so, it is possible to regulate the inner diameters of the openings 240 and 242 while preventing displacement between the mold 300 or the core 300 and the thermoplastic resin sheets P1 and P2 due to compression accompanying mold clamping, By using the core 300 on the outer surface of which the coating that exhibits non-adhesiveness to the plastic resin is used, the core 300 is moved relative to the pair of split molds 32A and 32B by regulating the inner diameter of the openings 240 and 242. When pulling out in a direction crossing the direction, as in the conventional case, the molten thermoplastic resin sticks to the outer surface of the core 300, thereby restricting the opening 2. Without the inner surface of 0,242 is roughened, it is smoothly possible withdrawal, generally, it is possible to restrict the inner diameter of the opening 240, 242 with high accuracy. Furthermore, by forming only by suction without applying the blowing pressure, the formed hollow portion expands when the split mold 32 is opened as in the case of molding by the conventional blowing pressure alone, and a desired volume is obtained. It is possible to avoid a situation in which it is difficult to mold the hollow portion.

  According to the molding apparatus having the above configuration, at least one of the two thermoplastic resin sheets P1 and P2 is sucked through the corresponding cavities 116A and B2 before the pair of split molds 32A and B are clamped. In order to prevent molding failure due to the two thermoplastic resin sheets P1 and P2 sticking to each other as the mold is clamped as in the past, the pair of split molds 32A, Without providing a sliding mold and an intermediate mold that can be disassembled and moved between the pair of split molds 32A and B in each B, good moldability while avoiding complication and enlargement of the molding apparatus Can be secured, and the core 300 having a coating that exhibits non-adhesiveness to the thermoplastic resin is applied to the outer surface, and the inner diameter of the openings 240 and 242 is regulated to divide the core 300 into a pair. Mold When pulling out in the direction crossing the relative movement direction of 2A and 2B, the inner surface of the restricted openings 240 and 242 is roughened by the molten thermoplastic resin sticking to the outer surface of the core 300 as in the prior art. Therefore, it can be pulled out smoothly, and the inner diameters of the openings 240 and 242 can be regulated with high accuracy.

Although the embodiments of the present invention have been described in detail above, various modifications or changes can be made by those skilled in the art without departing from the scope of the present invention.

For example, in the present embodiment, the extruded thermoplastic resin sheets P1 and P2 that have been extruded are described as being directly shaped and molded as the resin heat collector panel 200. However, the present invention is not limited thereto. As long as the melted state necessary for shaping and forming is realized, the thermoplastic resin sheets P1 and P2 that have been once extruded and cooled are reheated and utilized in a molten state. Shaping and molding may be performed.
Further, in the present embodiment, the molten thermoplastic resin sheets P1 and P2 extruded from the T-die in a sheet shape are used, but without being limited thereto, the molten cylindrical parison is crushed. It may be formed in a sheet shape.
In addition, in the present embodiment, the heat collector having a meandering internal flow path has been described. However, the present invention is not limited thereto, and is a hollow molded product having openings 240 and 242, and the openings As long as the inner and outer diameters of 240 and 242 are regulated, for example, a plurality of short curved pipes are simultaneously formed, or a hollow portion in which the tubular openings 240 and 242 are connected to the outer peripheral surface is formed. The present invention is also applicable to a hot water panel or the like in which a container having a plurality of straight pipes is formed, or side edges of a plurality of straight pipes are connected in parallel.

It is the schematic of the resin-made heat collector panels which concern on embodiment of this invention. It is a side view which shows the state by which the molten resin sheet was arrange | positioned between the division molds with the shaping | molding apparatus which concerns on embodiment of this invention. It is a schematic plan view of the shaping | molding apparatus which concerns on embodiment of this invention. It is a schematic sectional drawing which shows the circumference of a core when the division mold of the shaping | molding apparatus which concerns on embodiment of this invention exists in a mold clamping position. It is a schematic side view which shows the state which is making the outer frame of a division mold contact | abut to the side surface of a molten resin sheet in the shaping | molding apparatus which concerns on embodiment of this invention. In the shaping | molding apparatus which concerns on embodiment of this invention, it is a general | schematic fragmentary sectional view which shows the condition which is shaping the molten resin sheet. It is a figure which shows the state which clamped the division mold in the shaping | molding apparatus which concerns on embodiment of this invention. In the molding apparatus which concerns on embodiment of this invention, it is a figure which shows the state which opened the split mold. It is a partial schematic diagram showing the periphery of the inflow opening of the resin heat collector panel according to the embodiment of the present invention.

P Thermoplastic resin sheet 10 Molding device 12 Extruding device 14 Clamping device 16 Hopper 18 Cylinder 22 Hydraulic motor 24 Accumulator 26 Plunger 28 T die 30 Roller 32 Dividing mold 33 Mold frame 34 Extrusion slit 116 Cavity 118 Pinch off part 119 First 1 recess 120 second recess 121 third recess 123 fourth recess 200 collector panel 236 hot water discharge pipe 238 water injection pipe 240 inflow opening 242 outflow opening 300 core 302 mold attachment plate 304 tie bar 305 shoulder 306 pedestal 310 first 1 spring 312 2nd spring 314 end opening 316 communication hole 318 expanded diameter cut-off portion 322 inside diameter regulating portion 322
325 edge 327 end face

Claims (9)

A method for forming a hollow molded article having an opening,
A core having an outer shape complementary to the inner diameter of the opening and coated on the outer surface with a coating that is non-adhesive to the thermoplastic resin, and cavities surrounded by pinch-off portions are arranged opposite to each other, and are clamped A pair of split molds that are movable relative to each other between a position and a mold opening position, and each split mold cavity is provided with a recess that is complementary to the outer diameter of the opening. And the stage of preparing
The two thermoplastic resin sheets are spaced apart from each other and are disposed between the pair of split molds at the mold opening position in a form that protrudes from the cavity, and the opening to be formed in the thermoplastic resin sheet Depending on the position and orientation of the, in a form protruding inward from the pinch-off portion, the core is disposed between two thermoplastic resin sheets,
A sealed space is formed between at least one of the thermoplastic resin sheets and the corresponding molds of the pair of molds, and one of the thermoplastic resin sheets is sucked by decompressing air from the sealed space. And regulating the outer diameter of the opening by shaping along the corresponding cavity;
By moving the pair of split molds to the clamping position, two thermoplastic resin sheets are welded to form a hollow portion inside, and each of the two thermoplastic resin sheets can be handled. Regulating the inner diameter of the opening by sandwiching between the cavity and the outer shape of the core;
Opening the pair of split molds to a mold opening position, and pulling the core from the formed opening in a direction intersecting the relative movement direction of the pair of split molds;
The molding method using the core characterized by having. A method for forming a hollow molded article having an opening,
A core having an outer shape complementary to the inner diameter of the opening and coated on the outer surface with a coating that is non-adhesive to the thermoplastic resin, and cavities surrounded by pinch-off portions are arranged opposite to each other, and are clamped A pair of split molds that are movable relative to each other between a position and a mold opening position, and each split mold cavity is provided with a recess that is complementary to the outer diameter of the opening. And the stage of preparing
Two thermoplastic resin sheets are arranged between a pair of split molds at the mold opening position in such a manner that they are spaced from each other and protrude from the cavity, and at least one thermoplastic resin sheet and a pair of molds Forming a sealed space between the corresponding molds of the mold and reducing the air pressure from the sealed space, sucking one thermoplastic resin sheet and shaping it along the corresponding cavity To regulate the outer diameter of the opening,
In the thermoplastic resin sheet, depending on the position and orientation of the opening to be formed, the core is disposed between the two thermoplastic resin sheets in a form protruding inward from the pinch-off portion;
By moving the pair of split molds to the clamping position, two thermoplastic resin sheets are welded to form a hollow portion inside, and each of the two thermoplastic resin sheets can be handled. Regulating the inner diameter of the opening by sandwiching between the cavity and the outer shape of the core;
Opening the pair of split molds to a mold opening position, and pulling the core from the formed opening in a direction intersecting the relative movement direction of the pair of split molds;
The molding method using the core characterized by having. The said molded article is a molded article provided with the tubular part which one end is connected to the sealed hollow part, and the other end opens to the outer peripheral part of the molded article which has the sealed hollow part. A molding method using the core described in 1.   The molding method using the core according to claim 1 or 2, wherein the core is made of iron, and the coating is performed by an electroless composite plating method in which polytetrafluoroethylene fine particles are co-deposited in a nickel-phosphorus film. . The core has a rod-like shape having a communication hole extending in the longitudinal direction with an end opening provided at the distal end portion. The inner diameter regulating portion is formed on the outer surface of the distal end portion, and is adjacent to the inner diameter regulating portion in the longitudinally outward direction. And has an enlarged diameter push-cut part,
The core is made of a thermoplastic resin around the boundary between the opening and the hollow portion regulated by the inner diameter regulating portion by ejecting air from the end opening with the core projecting inward from the pinch-off portion. 2. The method according to claim 1, further comprising shaping a sheet and pressing a boundary portion between a lip portion and a burr portion of the opening portion by the enlarged diameter pressing and cutting portion when the pair of split molds are clamped. Molding method using the core. A molding apparatus for molding a hollow molded article having an opening using two thermoplastic resin sheets,
Each of the cavities surrounded by the pinch-off portions is opposed to each other, and is a pair of split molds that can move relative to each other between the clamping position and the mold opening position. A pair of split molds provided with recesses for regulating the outer diameter;
The core is movable between a holding position retracted outward from the pinch-off part and a protruding position protruding inward from the pinch-off part in a direction intersecting the relative movement direction of the pair of split molds. A core for regulating the inner diameter of the opening by the outer surface,
Suction for sucking the corresponding sheets of the two thermoplastic resin sheets disposed at a distance from each other between the pair of split molds provided in at least one of the split molds through the cavity An apparatus,
When each of the two thermoplastic resin sheets is compressed between the core and the corresponding cavity by moving the pair of split molds to the clamping position while the core is in the protruding position. The outer surface of the core is coated with a non-adhesive coating on the thermoplastic resin sheet so that the core can be smoothly pulled out toward the holding position. Molding equipment.   The molding apparatus according to claim 6, wherein the core is made of iron, and the coating is performed by an electroless composite plating method in which polytetrafluoroethylene fine particles are co-deposited in a nickel-phosphorus film.   Furthermore, a first urging means for urging the core toward one mold of the pair of split molds, and a first urging means for biasing the core toward the other mold of the pair of split molds. 2 urging means, and the core is in a balance position between the urging force by the first urging means and the urging force by the second urging means in the relative movement direction of the pair of split molds. The forming apparatus according to claim 6 or 7, wherein the forming apparatus is positioned. The core has a rod-like shape having a communication hole extending in the longitudinal direction with an end opening provided at the distal end portion. And has an enlarged diameter push-cut part,
The pair of split molds each of the cavities, the deeper recess second recess complementary shape to the opening, adjacent the enlarged press-cutting of the core of the projecting position is provided on the outside of the recess, claim The molding apparatus according to claim 6 or 7.

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