JP5141021B2 - Preform compression molding apparatus and preform compression molding method - Google Patents

Description

  The present invention relates to a preform compression molding apparatus and a preform compression molding method for molding a preform used for blow molding a container or the like, and in particular, the diameter of the molten resin is reduced or the molten resin is drawn down. The present invention relates to a preform compression molding apparatus and a preform compression molding method for reliably molding a wrinkle-free preform by

  Conventionally, when the preform is manufactured by compression molding, the molten resin 61 ′ is extruded vertically downward from the discharge port 7 of the extrusion apparatus 50 as shown in FIG. 8. The molten resin 61 'thus extruded may be drawn down due to the influence of gravity, and a portion 61'n having a small diameter may be generated. When such a molten resin 61 ′ is cut by a cutter to obtain a molten resin lump, which is put into a mold (not shown) and compression molded, a wrinkle is formed on the surface of the preform at a portion where the diameter of the molten resin lump is reduced. Sometimes formed. Further, when the draw down of the molten resin 61 ′ is large, the molten resin lump may be separated into two and compression molding itself may be impossible.

As a method for preventing such drawdown during compression molding, a drawdown is achieved by using a polyester resin containing 0.01 to 0.3 mol% of a polyfunctional component and having a melt tension of 40 mN or more. There is known a method for preventing the above (see Patent Document 1).
JP 2005-171081 A

  However, according to the invention of Patent Document 1, the properties of the resin material are determined to a certain degree, and various factors such as container performance, recyclability, blow moldability, resin production cost, and the like cannot be satisfied in a well-balanced manner.

  The present invention has been made in consideration of the above points, and it is possible to prevent the molten resin from being reduced in diameter and the molten resin from being drawn down and wrinkled regardless of the properties of the resin material. It is an object of the present invention to provide a preform compression molding apparatus and a preform compression molding method capable of molding a preform having no crack.

The present invention includes an extrusion device for extruding a molten resin upward from a discharge port;
A cutting support unit provided above the extrusion device and supporting the molten resin extruded upward from the side, and cutting the molten resin to generate a molten resin lump,
A transport mechanism that is provided above the extrusion device and transports the molten resin lump supported from the side by the cutting support portion to above the female die of the mold;
A preform compression molding apparatus.

  With such a configuration, it is possible to prevent the molten resin from being reduced in diameter and the molten resin from being drawn down and to form a wrinkle-free preform, regardless of the properties of the resin material.

  In the present invention, when the molten resin lump supported from the side by the cutting support portion is positioned above the female mold of the mold, the transport mechanism injects gas from above to the molten resin lump. It is a preform compression molding apparatus characterized by having a gas injection unit for charging a lump into a mold.

  With such a configuration, the molten resin lump supported from the side by the cutting support portion can be reliably put into the mold.

  The present invention is a preform compression molding apparatus in which an additional extrusion die having a supply hole arranged corresponding to a discharge port of the extrusion apparatus is detachably provided at the upper end of the extrusion apparatus.

  With such a configuration, even when the molten resin adheres to the additional extrusion die and becomes dirty, it can be removed and easily cleaned. Further, even if the additional extrusion die and the cutting support part interfere with each other and wear or break, it can be replaced with a new additional extrusion die, so that the maintenance cost can be kept low.

The present invention is an extrusion process for extruding a molten resin upward from a discharge port of an extrusion device;
A cutting support step for supporting the molten resin extruded upward from the side by a cutting support portion provided above the extrusion device, and cutting the molten resin to generate a molten resin lump,
A transporting step of transporting the molten resin mass supported from the side by the cutting support part to above the female mold of the mold by a transporting mechanism provided above the extrusion device;
A preform compression molding method characterized by comprising:

  With such a configuration, it is possible to prevent the molten resin from being reduced in diameter and the molten resin from being drawn down and to form a wrinkle-free preform, regardless of the properties of the resin material.

  The present invention further includes a charging step of injecting a molten resin lump into the mold by injecting a gas from above into the molten resin lump when the molten resin lump is positioned above the female mold of the mold. This is a preform compression molding method.

  With such a configuration, the molten resin lump supported from the side by the cutting support portion can be reliably put into the mold.

  According to the present invention, since the molten resin is extruded upward by the extrusion device, the diameter of the molten resin is prevented from being reduced or the molten resin is not drawn down regardless of the properties of the resin material. It is possible to form a preform without wrinkles.

First Embodiment A first embodiment of a preform compression molding apparatus and a preform compression molding method according to the present invention will be described below with reference to the drawings. Here, FIG. 1 thru | or FIG. 6 is a figure which shows the 1st Embodiment of this invention.

  As shown in FIGS. 1 and 4, the preform compression molding apparatus is an extrusion apparatus 50 for extruding a molten resin 61 ′ obtained by melting a pellet-shaped resin upward from a discharge port 7 having a circular cross section. And a cutting support unit 10 provided above the extrusion device 50 and supporting the molten resin 61 ′ extruded upward from the side, and cutting the molten resin 61 ′ to generate a molten resin lump 61. A circular resin supply rotary (conveying mechanism) 25 that is provided above the extrusion device 50 and conveys the molten resin mass 61 supported from the side by the cutting support portion 10 to above the female die 31 of the mold 30. I have. The molten resin 61 'is made of a thermoplastic resin such as polyethylene terephthalate, polypropylene, polylactic acid (PLA).

As shown in FIGS. 1 to 3, the cutting support portion 10 is provided on the lower surface of the resin supply rotary 25. Further, as shown in FIG. 4, the resin supplying rotary 25 is rotatable in the R ₁ direction.

  1 to 4, the cutting support portion 10 is provided on the lower surface of the resin supply rotary 25, and a pair of resin guides 16 for supporting the molten resin 61 'extruded upward from the side. , 17 and a pair of resin guides 16, 17, a cutter (cutting part) that cuts the molten resin 61 ′ supported from the side by the pair of resin guides 16, 17 to generate a molten resin lump 61. 15). Further, as shown in FIG. 4, a plurality of cutting support portions 10 are provided in a circumferential shape on the lower surface of the resin supply rotary 25.

  As shown in FIG. 1, the extrusion device 50 includes an extruder 1 that melts and extrudes pellet-shaped resin, a gear pump that is provided on the downstream side of the extruder 1 and supplies a certain amount of molten resin 61 ′, and the like. The fixed quantity supply apparatus 2 which consists of these. Depending on the accuracy required for the preform 60 (see FIG. 5) to be molded, the performance of the extruder 1, and the like, the fixed amount supply device 2 can be omitted.

  As shown in FIGS. 1 and 4, the extrusion apparatus 50 includes an extrusion die 3 having a supply path 6 that guides the molten resin 61 ′ supplied from the quantitative supply apparatus 2 to the discharge port 7 provided on the upper surface. Contains.

  As shown in FIGS. 1 and 3, when the molten resin lump 61 supported from the side by the cutting support portion 10 is positioned above the female die 31 of the mold 30, A gas injection unit 21 for injecting a molten resin mass 61 into the mold 30 by injecting a gas such as air or nitrogen into the molten resin mass 61 from above is provided.

As shown in FIGS. 1 to 3, the gas injection unit 21 is located between the pair of resin guides 16 and 17 on the lower surface of the resin supply rotary 25 and in front of the rotation direction R ₁ of the resin supply rotary 25. And a gas inflow passage 22 for guiding gas from a gas supply device (not shown) to the injection port 23.

  Further, as shown in FIG. 3, the mold 30 is arranged so as to face the female mold 31 into which the molten resin lump 61 is put and the female mold 31, and is inserted into the female mold 31. The male mold 32 that compresses the molten resin lump 61 put into the mold 31 to generate the preform 60, and the slide mold that is provided above the female mold 31 and on the side of the male mold 32 and is slidable in the horizontal direction. 33.

As shown in FIG. 4, a plurality of such molds 30 are circumferentially provided on a circular molding rotary 35 provided on the downstream side of the resin supply rotary 25. The molding rotary 35 is rotatable in the R ₂ direction. By the way, in the present application, “downstream” means being downstream in the process of molding the preform 60 from a pellet-shaped resin.

Further, as shown in FIG. 4, on the downstream side of the molding rotary 35, a housing part 42 for discharging and housing the preform 60 molded by the mold 30, and a preform 60 housed in the housing part 42. And a circular transport rotary that transports the water to the discharge path 43. The conveyance rotary is rotatable in R ₃ direction.

  Next, the operation of the present embodiment having such a configuration will be described.

  First, pelletized resin is supplied to the extruder 1 by a supply device (not shown).

Next, in the extruder 1, the pellet-shaped resin is melted to become a molten resin 61 ′, and a fixed amount of the molten resin 61 ′ is supplied to the extrusion die 3 of the extrusion device 50 by the quantitative supply device 2 (FIG. 1). reference). Thereafter, the molten resin 61 ′ is guided to the discharge port 7 provided on the upper surface of the extrusion die 3 through the supply path 6 and extruded upward from the discharge port 7 (extrusion process) (see FIG. 1). . At this time, the resin supply rotary 25 is rotated in the R ₁ direction (see FIG. 4).

  Thus, since the molten resin 61 'is pushed upward, the molten resin 61' does not extend due to its own weight. For this reason, the diameter of the molten resin 61 ′ can be prevented from being reduced and the molten resin 61 ′ can be prevented from being drawn down regardless of the properties of the resin material.

  Next, the molten resin 61 ′ extruded upward from the discharge port 7 of the extrusion device 50 is laterally formed by a pair of resin guides 16 and 17 of the cutting support portion 10 provided on the lower surface of the resin supply rotary 25. While being supported, it is cut by the cutter 15 of the cutting support portion 10 to generate a molten resin mass 61 (cutting support step) (see FIGS. 1 and 4).

  As described above, the molten resin 61 ′ is fixed to the lower surface of the resin supply rotary 25 while being supported from the side by the resin guides 16 and 17, and is cut by the cutter 15 having no movable part. For this reason, the molten resin 61 ′ is unlikely to scatter and it is possible to prevent the molten resin 61 ′ from adhering to the preform compression molding apparatus and causing malfunction.

  Next, the molten resin lump 61 is conveyed by the resin supply rotary 25 to above the female mold 31 of the mold 30 while being supported by the pair of resin guides 16 and 17 of the cutting support portion 10 and the cutter 15 (conveyance). (Process) (refer FIG. 2 and FIG. 4). Specifically, the molten resin lump 61 is in contact with the cutter 15 by inertial force, and is in contact with the resin guide 16 by centrifugal force acting radially outward, while the female mold 31 of the mold 30 is formed by the resin supply rotary 25. (See FIGS. 2 and 4). By the way, as shown in FIGS. 2 and 4, since the resin guide 17 is also provided inward in the radial direction of the fusible resin material lump 61, the molten resin lump 61 is conveyed while being supported in a more stable state. be able to.

  Next, when the molten resin lump 61 is positioned above the female mold 31 of the mold 30 provided in the molding rotary 35, gas is emitted from the injection port 23 of the gas injection unit 21 positioned above the molten resin lump 61. The molten resin lump 61 is injected into the female die 31 of the mold 30 (injecting step) (see FIGS. 3 and 4). For this reason, the molten resin lump 61 supported by the pair of resin guides 16 and 17 of the cutting support portion 10 and the cutter 15 can be reliably put into the female die 31 of the mold 30.

  At this time, as shown in FIG. 4, the mold 30 is opened so that the female mold 31 is positioned below the resin supply rotary 25 and the male mold 32 and the slide mold 33 are positioned above the resin supply rotary 25. Yes.

Next, the two slide molds 33 are moved and closed in the horizontal direction, and are in close contact with the female mold 31 (see FIG. 3). Thereafter, the male die 32 is inserted into the female die 31 by the push rod 39, and the molten resin lump 61 introduced into the female die 31 is compressed (see FIG. 3). As a result, a preform 60 based on the shapes of the female die 31, the male die 32, and the slide die 33 is generated (see FIG. 5). At this time, the molding rotary 35 is rotated in the _{R 2} direction (see FIG. 4).

Next, when the preform 60 generated in the mold 30 comes near the accommodating portion 42 provided in the discharge rotary 45, the mold 30 is opened again. Then, the generated preform 60 is discharged from the mold 30 and accommodated in the accommodating portion 42. Thereafter, the preform 60 which is received in the receiving section 42 is conveyed to the discharge path 43 by the discharge rotary 45 rotating in the R ₃ direction (see FIG. 4).

  As described above, according to the present invention, since the molten resin 61 ′ is pushed upward from the discharge port 7 of the extrusion die 3, the molten resin 61 ′ does not extend due to its own weight. For this reason, the diameter of the molten resin 61 ′ can be prevented from being reduced and the molten resin 61 ′ can be prevented from being drawn down regardless of the properties of the resin material. As a result, it is possible to efficiently produce a preform 60 having no wrinkles and excellent quality.

  In the above description, the pair of resin guides 16 and 17 disposed radially inward and outward in the radial direction with respect to the molten resin lump 61 has been described. On the other hand, the resin guide 16 may be provided only radially outward (that is, only radially outward with respect to the cutter 15).

  Moreover, although demonstrated above using the cutting | disconnection support part 10 which consists of a pair of resin guides 16 and 17 and the cutter 15 provided between a pair of resin guides 16 and 17, it is not restricted to this, For example, Further, it is possible to use a cutting support portion 10 made of an arcuate cutter 19 as shown in FIG.

Second Embodiment Next, a second embodiment of the present invention will be described with reference to FIG. In the second embodiment shown in FIG. 7, an additional extrusion die 8 having a supply hole 9 arranged at the upper end of the extrusion die 3 of the extrusion device 50 corresponding to the discharge port 7 of the extrusion device 50 is removable. The other configurations are substantially the same as those of the first embodiment shown in FIGS.

  In the second embodiment shown in FIG. 7, the same parts as those in the first embodiment shown in FIGS. 1 to 6 are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in FIG. 7, an additional extrusion die 8 having a supply hole 9 disposed corresponding to the discharge port 7 of the extrusion device 50 is detachably provided at the upper end of the extrusion die 3 of the extrusion device 50. . Specifically, as shown in FIG. 7, the extrusion die 3 has a tapered portion 3 ', and the additional extrusion die 8 has a recess 8' that engages with the tapered portion 3 '. The extrusion die 3 and the additional extrusion die 8 are connected by a connecting member (not shown) such as a screw.

  In FIG. 7, the additional extrusion die 8 is detachable from the extrusion die 3, so that even when the molten resin 61 ′ adheres to the additional extrusion die 8 and becomes dirty, it can be removed and washed easily. Can do. Further, even if the additional extrusion die 8 and the cutter 15 interfere with each other and are worn or damaged, it can be replaced with a new additional extrusion die 8, so that the maintenance cost can be kept low.

  In addition, by preparing a plurality of additional extrusion dies 8 having different supply holes 9, it is possible to appropriately generate molten resin lumps 61 having different diameters by simply replacing the additional extrusion dies 8. For this reason, it is possible to easily generate an appropriate molten resin lump 61 in accordance with the size and shape of the preform 60 to be molded.

Sectional drawing which shows the extrusion apparatus, the cutting | disconnection support part, and resin supply rotary of the preform compression molding apparatus by the 1st Embodiment of this invention. The perspective view of the cutting | disconnection support part of the preform compression molding apparatus by the 1st Embodiment of this invention. Sectional drawing which shows the metal mold | die, cutting | disconnection support part, and resin supply rotary of the preform compression molding apparatus by the 1st Embodiment of this invention. Sectional drawing which shows the preform produced | generated by the preform compression molding apparatus and preform compression molding method by the 1st Embodiment of this invention. The top view of the preform compression molding apparatus by the 1st Embodiment of this invention. The perspective view of the cutting | disconnection support part of the preform compression molding apparatus by the modification of the 1st Embodiment of this invention. Sectional drawing of the extrusion apparatus of the preform compression molding apparatus by the 2nd Embodiment of this invention. Sectional drawing of the extrusion apparatus of the conventional preform compression molding apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Extruder 2 Fixed_quantity | feed_rate supply apparatus 3 Extrusion die 3 'Taper part 6 Supply path 7 Discharge port 8 Additional extrusion die 8' Concave 9 Supply hole 10 Cutting support part 15 Cutter (cutting part)
16 Resin guide 17 (radially outward) Resin guide 21 (radially inward) Gas injection part 22 Gas inflow path 23 Injection port 25 Resin supply rotary (conveyance mechanism)
30 Mold 31 Female mold 32 Male mold 33 Slide mold 35 Molding rotary 39 Push rod 42 Housing part 43 Discharge path 45 Discharge rotary 50 Extrusion device 60 Preform 61 Molten resin lump 61 ′ Molten resin

Claims (5)

An extrusion device for extruding the molten resin upward from the discharge port;
A cutting support unit provided above the extrusion device and supporting the molten resin extruded upward from the side, and cutting the molten resin to generate a molten resin lump,
A transport mechanism for transporting the molten resin mass supported from the side by the cutting support part to above the female mold of the mold;
Equipped with a,
The cutting support portion is provided between the pair of resin guides and a pair of resin guides provided below the transport mechanism and supporting the molten resin pushed upward from the side. A preform compression molding apparatus comprising: a cutting portion that cuts the molten resin supported from the side by a resin guide to generate the molten resin lump .   When the molten resin lump supported from the side by the cutting support portion is positioned above the female mold of the mold, the transport mechanism injects gas from above to the molten resin lump, The preform compression molding apparatus according to claim 1, further comprising a gas injection unit that is introduced into the preform.   2. The preform compression molding apparatus according to claim 1, wherein an additional extrusion die having a supply hole arranged corresponding to a discharge port of the extrusion apparatus is detachably provided at an upper end of the extrusion apparatus. An extrusion process for extruding the molten resin upward from the discharge port of the extrusion device;
A cutting support step for supporting the molten resin extruded upward from the side by a cutting support portion provided above the extrusion device, and cutting the molten resin to generate a molten resin lump,
A transport step of transporting the molten resin mass supported from the side by the cutting support portion to above the female die of the mold by the transport mechanism;
Equipped with a,
The cutting support part has a pair of resin guides provided below the transport mechanism, and a cutting part provided between the pair of resin guides,
In the cutting support step, the pair of resin guides supports the molten resin extruded upward from the side, and the cutting portion cuts the molten resin supported from the side by the pair of resin guides. To produce a molten resin mass .   When the molten resin lump is positioned above the female mold of the mold, it is further provided with a charging step of injecting a gas from above into the molten resin lump and charging the molten resin lump into the mold. The preform compression molding method according to claim 4.

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