JP6595361B2 - Blow molding apparatus and blow molding method - Google Patents

Description

  The present invention relates to a technology for manufacturing a synthetic resin molded product (plastic bottle, etc.) by blow molding (hollow molding, direct blow molding), and in particular, with a simple manufacturing device at an inexpensive manufacturing cost, the inner surface (inner circumference) Technology that can produce molded products with different colors or linear patterns or spiral patterns of the same color on at least one surface (peripheral surface) of the outer surface and outer surface (peripheral surface) Apparatus, blow molded article and blow molding method). The blow-molded product according to the present invention is not limited to a plastic bottle.

Blow-molded containers (plastic bottles), which are a type of blow-molded product made of synthetic resin, have been used for a variety of applications. For cosmetics, where the decorativeness of the container occupies a large part of the product power. In shampoo and other containers, they are made different from other companies' products by exhibiting their decorative properties by painting, printing, labeling, etc.
As a method for producing such a plastic bottle, direct blow molding, biaxial stretch blow molding, injection blow molding and the like are widely used. As disclosed in Japanese Patent Application Laid-Open No. 07-214653 (Patent Document 1), the direct blow molding method uses a cylindrical parison (substantially hollow cylindrical tube) extruded from an extruder as a pair of blow molds. A hollow product is formed by blowing compressed air into the inside of the sandwiched parison (hollow cylindrical portion).

For the purpose of giving a decorative effect to the plastic bottle manufactured by such a direct blow molding method, a vertical stripe or spiral pattern may be provided on the side of the bottle.
In order to mold these patterns on the outer surface of the side surface of the plastic bottle in the blow molding method, there is a method of first engraving a mold and expressing the pattern on the outer surface by following the resin with the pressure of air blown into the mold. It was general. However, in the processing of a mold for applying a stripe pattern or the like, there is a drawback in that the number of steps is increased because the concave portion must be three-dimensionally engraved, and the manufacturing cost is increased. Furthermore, the bottles with irregularities on the outer surface by mold engraving have the disadvantage that subsequent decorations, especially printing and stamping, are difficult. Furthermore, when the bottle is used as a container for highly viscous liquids such as cosmetic liquids, if the inner surface of the bottle is smooth, when the bottle is tilted, the entire mouth may be blocked with liquid and air can be taken in smoothly. There was a problem that it took time to discharge the liquid.

  In view of such a problem, Japanese Patent Application Laid-Open No. 2001-322161 (Patent Document 2) discloses a method of forming these patterns on the inner surface of the side surface of a plastic bottle in a blow molding method. This patent document 2 discloses a method for producing a bottle with an inner surface pattern by blow molding, characterized in that a spiral groove is provided on the side of an injection core in the plastic bottle production process.

  According to this manufacturing method, since the spiral groove is engraved on the side surface of the injection core, the molten resin having a certain plasticity extruded from the extruder advances along the spiral groove, and the extruder The parison discharged from the annular opening also advances while rotating, and a spiral pattern that complements the spiral groove is sequentially formed on the inner surface of the parison. By blow molding this parison, a plastic bottle having a spiral pattern on the inner surface of the side surface and a smooth outer surface can be obtained.

JP 07-214653 A JP 2001-322161 A

  However, in the manufacturing method disclosed in Patent Document 2, it is necessary to provide a spiral groove on the side surface of the injection core even if a plastic bottle having a spiral pattern on the side surface and a smooth outer surface can be obtained. It cannot be manufactured using a general blow molding machine. In particular, since the spiral groove provided on the side surface of the injection core is not straight, there is a possibility that the extrusion performance of the molten resin may be reduced due to resistance when the molten resin is extruded, and that the molten resin is released from the injection core. The possibility of difficulty can not be excluded. In order to eliminate such a possibility, the extrusion mechanism must be improved, so that the structure of the apparatus becomes complicated and the manufacturing cost of the molded product increases. For this reason, in the manufacturing method disclosed in Patent Document 2, it is highly likely that it is difficult to manufacture a molded product having a spiral pattern on the inner surface of the side surface with a simple manufacturing apparatus and at a low manufacturing cost.

  The present invention has been developed in view of the above-described problems, and the object of the present invention is to provide an inner surface (inner peripheral surface) and an outer surface of a side surface at a low manufacturing cost with a simple manufacturing apparatus in blow molding ( A blow molding device, a blow molded product and a blow molded product capable of producing a molded product having a different color or a linear pattern or spiral pattern of the same color on at least one surface (peripheral surface) of the outer peripheral surface) It is to provide a blow molding method.

In order to achieve the above object, the blow molding apparatus according to the present invention employs the following technical means.
That is, the blow molding apparatus according to the present invention is a molding apparatus for producing a molded product made of synthetic resin by a blow molding method, and the inner circumference of a substantially hollow cylindrical base layer obtained by heating and melting the first molding material. A parison having a non-annular cross-sectional shape formed so as to protrude from at least one of the peripheral surface and the outer peripheral surface and having one or more convex portions formed along the extrusion direction of the parison is formed below the die head. And a blow molding mechanism for sandwiching the extruded parison with a mold and blow molding, and the convex portion is a first molding material forming the base layer in the die head. The resin passages are formed of different second molding materials.

Preferably, the die head includes a housing and two or more mandrels. The first resin passage through which the heat-melted first molding material flows and the heat-melted second molding material flow. A second resin passage, and the first resin passage and the second resin passage may be configured not to merge inside the die head.
More preferably, the color of the first molding material and the color of the second molding material can be different.

  More preferably, the blow molding device further includes a twisting mechanism for gripping and twisting the parison extruded from the push-out mechanism, and the blow-molding mechanism is configured to use the parison twisted by the twisting mechanism as a metal. The twisting mechanism is sandwiched between molds and blow-molded. The twisting mechanism includes a gripping means for gripping an end of the parison extruded from the push-out mechanism, and an axis parallel to the push-out direction of the parison as a rotation axis. And a rotating means for rotating the gripping means that grips the end portion by a predetermined angle.

More preferably, the push-out mechanism continuously pushes out the parison, and the twisting mechanism has a gripping means that grips an end of the parison corresponding to the push-out speed of the parison along the rotational axis direction. A moving means for moving downward may be further included.
More preferably, the push-out mechanism pushes out the parison while circulating air through the hollow portion of the parison in order to maintain the substantially hollow cylindrical shape of the parison, and the gripping means does not hinder the flow of air. In addition, it can be configured to grip the end of the parison.

More preferably, the blow molding mechanism blow-molds a parison released from gripping by the gripping means, and the predetermined angle is a twist angle in the molded product after the blow molding, and the parison released from gripping. Can be configured such that the angle is added by an angle corresponding to the angle returned until it is sandwiched between the molds.
More preferably, the blow molding mechanism blow-molds a parison released from gripping by the gripping means, and the gripping means sandwiches the outer cylindrical surface of the end of the parison with a pair of chucks, and the mold Is a mold divided into at least two facing mating surfaces separated from each other, wherein the rotating means is formed by being held by the chuck in the parison where the chuck is released. It can be configured that the rotation of the gripping means that grips the end of the parison is stopped so that a flat surface is substantially parallel to the plane including the mating surface.

Moreover, the blow molded product which concerns on another aspect of this invention is manufactured with the blow molding apparatus mentioned above.
A blow molding method according to still another aspect of the present invention is a molding method for producing a molded product made of synthetic resin by a blow molding method, and has a substantially hollow cylindrical shape obtained by heating and melting the first molding material. A parison having a non-circular cross-sectional shape formed so as to protrude from at least one of the inner peripheral surface and the outer peripheral surface of the base layer and having one or more convex portions formed along the direction of extrusion of the parison. , An extrusion step of extruding downward from a die head, and a molding step of sandwiching the extruded parison with a mold and blow molding, wherein the convex portion is the first molding material forming the base layer The resin passages in the die head are formed of different second molding materials.

  According to the present invention, in blow molding, at least one surface (peripheral surface) of the inner surface (inner peripheral surface) and the outer surface (outer peripheral surface) of the side surface is different in color or the same at a low cost with a simple manufacturing apparatus. It is possible to provide a blow molding apparatus, a blow molded product, and a blow molding method capable of producing a molded product on which a color linear pattern or spiral pattern is applied.

It is a perspective view showing the whole blow molding device concerning an embodiment of the invention. It is a front view which shows the whole blow molding apparatus shown in FIG. It is a side view which shows the whole blow molding apparatus shown in FIG. FIG. 3 is an enlarged view of a twisting mechanism (chuck unit) in FIG. 2. It is FIG. (1) for demonstrating operation | movement of a chuck | zipper unit. FIG. 6 is a second diagram for explaining the operation of the chuck unit; It is a control block diagram of the blow molding apparatus shown in FIG. It is a timing chart for demonstrating operation | movement of the blow molding apparatus shown in FIG. It is a perspective view for demonstrating the container manufactured with the blow molding apparatus shown in FIG. It is a figure for demonstrating the dice head which manufactures the parison shown to FIG. 9 (A). It is a figure for demonstrating the die head in the blow molding apparatus which concerns on the modification of this invention. It is a figure for demonstrating the die head applicable to the blow molding apparatus which concerns on the modification of this invention.

  Hereinafter, a blow molding apparatus 10 according to an embodiment of the present invention will be described with reference to the drawings. Since the drawings shown below are schematic diagrams, there are parts in a state where the support members of some parts are not described and are floating in the air, and are necessary for operating the blow molding apparatus 10. Drive equipment (motor, air cylinder, etc.) and control equipment (photoelectric sensor, proximity sensor, etc.) may not be described. In addition, although described in a confirming manner, there is no difference in meaning between “extrusion” and “extrusion”.

  In the following description, the molded product manufactured by the blow molding apparatus according to the embodiment of the present invention will be described as a plastic bottle B (hereinafter sometimes simply referred to as a bottle) B. It is not limited to such a molded product, and may be a molded product (for example, an air duct for automobiles) that can be manufactured by hollow molding or direct blow molding.

  In the following, a known direct blow molding machine (mainly composed of an extrusion unit, a mold unit, and a blow unit) is used. (1) A slit is formed in the core of the die head of the extrusion unit to form the inner cylinder surface of the parison. Although the blow molding apparatus 10 which provided the longitudinal groove and added the chuck | zipper unit (twisting mechanism) which pinches and twists the lower end part of the parison before shaping | molding after extrusion is demonstrated, it is limited to this. It is not a thing. The blow molding apparatus 10 can blow-mold three molded products at a time (in one cycle time), but is not limited to three, and may be one or more.

[overall structure]
FIG. 1 is a perspective view showing the whole blow molding apparatus 10 according to the present embodiment, FIG. 2 is a front view showing the whole blow molding apparatus 10, and FIG. 3 is a side view showing the whole blow molding apparatus 10. FIG. 4 shows an enlarged view of the chuck unit (twisting mechanism) 100 in FIG.
As shown in these drawings, in this blow molding apparatus 10, an extruding unit (extrusion mechanism) 200 that extrudes a parison P, in which a molding material is heated and melted, downward from a die head 220 and a facing mating surface are spaced apart from each other. A blow molding unit (blow molding mechanism) 300 that sandwiches the parison P by the mold 310 divided into two parts, blows air into the parison P sandwiched by the mold 310 and blow-molds it into the shape of the bottle B, and an extrusion unit The chuck unit 100 is configured to grip and twist the parison P pushed out from 200.

Here, the moving direction of each unit will be described.
In the chuck unit 100, the chuck 110 is movable in the horizontal direction indicated by arrows X (1) and X (2) and in the vertical direction indicated by arrows Z (1) and Z (2). The blow head 330 is movable in the horizontal direction indicated by arrows X (3) and X (4) and in the horizontal direction indicated by arrows Y (3) and Y (4). ) And Z (6) are configured to be movable in the vertical direction.

  Further, although the arrow is not shown, when the die head 220 in the extrusion unit 200 is movable in the Z direction, the cutter unit 240 is movable in a horizontal plane, and the cutter unit 240 is operated, The cutter unit 240 moves in the horizontal plane from the position and moves in the horizontal plane to cut the parison P sandwiched between the molds 310. After the operation of the cutter unit 240 is completed, the die head 220 moves in the Z direction. Move downward and return to the home position.

  The blow molding apparatus 10 is a molding apparatus for producing a synthetic resin molded product (here, bottle B) by a blow molding method, and includes a die head 220 and a molding material (limited) provided from a hopper 210. Although it is not a thing, in many cases, a substantially hollow cylindrical parison P obtained by heating and melting chips of polyethylene (PE), polypropylene (PP), polystyrene (PS), etc. is provided with one or more longitudinal grooves H on the inner cylindrical surface thereof. (See FIG. 9A), an extrusion unit 200 that pushes downward from the die head 220, a chuck unit 100 that grips and twists the parison P extruded from the extrusion unit 200, and twists by the chuck unit 100 A blow molding unit 300 for sandwiching (twisted and twisted) parison P between molds 310 and performing blow molding. In constructed. The chuck unit 100 includes a chuck 110 that grips an end portion (more specifically, a lower end portion) of the parison P extruded from the extrusion unit 200, and an end of the parison P with an axis parallel to the extrusion direction of the parison P as a rotation axis. And a rotary servo motor 1130 for rotating the chuck 110 holding the part by a predetermined angle.

  Here, the longitudinal groove provided in the parison P may be one or more longitudinal grooves. Further, by providing a slit (groove) in the core of the die head 220 that houses the die and the core, a convex portion G is formed on the inner surface of the inner cylindrical surface of the parison P corresponding to the slit portion provided in the core. A vertical groove H (concave portion) is formed on the inner surface of the inner cylindrical surface of the parison P corresponding to a portion other than the slit provided in the core. In the present invention, if there is at least one of the convex portion G (other than the vertical groove H) on the inner surface of the parison P and the vertical groove H on the inner surface of the parison P, the inner surface of the bottle A pattern can be formed.

  The extrusion unit 200 includes a die head 220 that extrudes such a parison P. The die head 220 is formed so as to protrude from at least one of the inner peripheral surface and the outer peripheral surface of the substantially hollow cylindrical base layer obtained by heating and melting the molding material, and is formed along the direction in which the parison P is extruded. The parison P having a non-annular cross-sectional shape including one or more convex portions G is pushed downward from the die head 220.

The die head 220 is not limited, but as an example, the die head 400 shown in FIG. 10 is employed.
Refer to the partial cross-sectional view of the die head 400 shown in FIG. 10A, the partial bottom view of the die head 400 shown in FIG. 10B, and the partially enlarged view of FIG. 10B shown in FIG. The die head 400 will be described. In FIG. 10, the resin supply mechanism, such as an extruder, a plunger, and an accumulator, are not shown because they are known techniques.

  The die head 400 is generally constituted by a die housing 410 in which a mandrel 420 is inserted on the center axis side and a die (die) 480 provided below the die housing 410. The die head 400 shown in FIG. 10 is a so-called side-feed method in which a molding material heated and melted is supplied from one side of the die head 400, and is a molding material in a high-temperature molten state pressed by a resin supply mechanism. Is supplied to the resin passage 450A and the resin passage 450B through the resin supply port 430 and the manifold 440 connected to the resin supply port 430. The manifold 440 has a semicircular cross-sectional shape that branches halfway to the left and right in the circumferential direction of the mandrel 420 and curves in the extrusion direction with a predetermined curvature while gradually decreasing the passage cross-sectional area at a predetermined ratio. The manifold 440 distributes and supplies the molding material heated and melted to the annular resin passage 450A and the annular resin passage 450B located downstream, and a uniform annular flow occurs in the resin passage 450A and the resin passage 450B. It is formed.

  The molding material heated and melted is provided between the die housing 410 and the mandrel 420, and the annular resin passage 450A provided between the die housing 410 and the mandrel 420, and between the die 480 and the mandrel 420 connected to the resin passage 450A. It passes through the annular resin passage 450B and is discharged from the lowermost annular space passage 460 to form the parison P. A core 470 is provided at the lowermost end of the die head 400, and the core 470 is connected to a parison (parison control) rod 490 that penetrates the mandrel 420, and is slightly advanced in the vertical direction by the operation of the paricon cylinder. In order to control the wall thickness, the gap (gap) of the annular space passage 460 can be adjusted.

In the present invention, a slit (groove) 472 is provided in the core 470, and a convex portion G (FIG. 9) is provided on the inner surface of the inner cylindrical surface of the parison P corresponding to the slit 472. (See (A)) is formed.
That is, the molding material discharged from the annular space passage 460 forms a base layer of the parison P, and the molding material discharged from the slit 472 forms a convex portion G that is a decorative portion of the parison P. The parison P having an annular cross section is pushed downward from the die head 220.

The chuck 110 described above is described as chucking the outer cylindrical surface of the parison P. However, even if the inner cylindrical surface of the parison P is widened from the inside, the outer cylindrical surface and / or the inner surface of the parison P can be obtained. The cylinder surface may be sucked and held.
In the blow molding apparatus 10, the extrusion unit 200 continuously extrudes the parison P. When the chuck 110 of the chuck unit 100 holds the lower end portion of the parison P, the extrusion unit 200 corresponds to the extrusion speed of the parison P. Thus, the chuck unit 100 moves downward (in the direction of arrow Z (2)) along the rotation axis direction.

  In the blow molding apparatus 10, the extrusion unit 200 pushes out the parison P while circulating air through the hollow portion of the parison P in order to push out the parison P while maintaining the hollow cylindrical shape shown in FIG. When the air flow path is closed when the chuck 110 of the chuck unit 100 holds the lower end of the parison P, the air escape is lost and the parison P expands. The lower end of the parison P is clamped so as not to hinder the air flow.

  In this blow molding apparatus 10, the blow molding unit 300 blow-molds the parison P released from being held by the chuck 110. In this case, the parison released from holding by the chuck 110 is the mold 310. Since the twisting force is not acting on the parison P until it is pinched (because the upper end of the parison P is gripped by the dice head 220, the lower end becomes a free end), the twist may return. is there. In such a case, if blow molding is performed as it is, a desired pattern cannot be applied to the inner surface of the bottle B. For this reason, the predetermined angle at which the parison P is rotated by the chuck unit 100 is the angle at which the parison P after the chuck 110 is released is sandwiched between the molds 310 by the twist angle in the blow molded product. An extra angle is added for the corresponding angle.

Here, the description has been made assuming that the parison P is blow-molded by releasing the clamping by the chuck 110, but the present invention may be such that the parison P is blow-molded without releasing the clamping by the chuck 110. In the case where the holding of the outer peripheral surface of the parison P by the chuck 110 is released and the parison P is blow-molded, the following modes are also conceivable.
When the chuck 110 holds the outer cylindrical surface of the lower end portion of the parison P between the pair of chucks 110 and releases the pinching, the parison P is in contact with the outside air temperature, and the temperature of the parison P is lowered. Without returning to the original cylindrical shape, the lower end portion of the parison P held by the chuck 110 is deformed to form a substantially flat plane (see FIG. 6D). In this case, when the mating surface opposed to the mold 310 is a mold that is divided into two that are spaced apart, the substantially flat plane at the deformed lower end of the parison P is a plane that includes the mating surface. If they are not substantially parallel, a distorted pattern may be formed on the bottom surface of the bottle B due to the reason that a substantially flat plane becomes a resistance when the mold 310 approaches and the mating surfaces are pressed against each other. Therefore, the lower end of the parison P is located at a position where a substantially flat plane formed by being held by the chuck 110 in the parison P with the chuck 110 released is substantially parallel to a plane including the mating surface of the mold 310. The rotation of the chuck 110 sandwiching the portion is stopped (see FIGS. 6D and 6E).

  The blow molding apparatus 10 according to the present embodiment having such a feature will be described in more detail with the chuck unit 100 as a center, with reference to FIGS. 5 and 6 are diagrams for explaining the operation of the chuck unit 100, FIG. 7 is a control block diagram of the blow molding device 10, and FIG. 8 explains the operation of the blow molding device 10. FIG. 9 is a perspective view for explaining the bottle B manufactured from the parison P by the blow molding apparatus 10.

[Each component configuration]
-Chuck unit The chuck unit 100 is a characteristic unit that the blow molding apparatus 10 according to the present invention uniquely has without including a general direct blow molding apparatus.
The chuck unit 100 includes a chuck 110 composed of a pair of claws 112 that sandwich the lower end of the parison P, a rotation mechanism such as a rotation servo motor 1130 that rotates the chuck 110, and a horizontal movement that horizontally moves the chuck 110. A horizontal movement mechanism such as a servo motor 1110 and a horizontal slide base 140, a horizontal movement mechanism such as a vertical movement servo motor 1120 and a vertical slide base 130 for moving the chuck 110 up and down, and a chuck air cylinder 1140 for opening and closing the chuck 110 Consists of

  As shown in FIG. 5, the chuck 110 includes a pair of claws 112 that sandwich the lower end portion of the parison P. By operating the chuck air cylinder 1140, the chuck 110 is closed in the direction indicated by the arrow C (1) or indicated by the arrow C (2). Or open in any direction. The claw 112 is made of, for example, aluminum, and at least a portion where the parison P abuts on the claw 112 is coated with, for example, fluorine, and the claw 112 is closed in the direction of arrow C (1) and the claw 112 is sandwiched between When 112 is opened in the direction indicated by arrow C (2), the parison P is easily separated from the claw 112 (it is not possible to proceed to the next step unless it is separated), and the operation of the blow molding device 10 is not hindered.

  Here, as shown in FIG. 5B, when the claw 112 is closed in the direction of the arrow C (2) because the chuck 110 of the chuck unit 100 holds the lower end portion of the parison P, the claws 112 Restricting members provided at the bases of the respective claws 112 before contact with each other (in this case, constituted by bolts 114 and female screws cut into through holes of members of the base parts of the claws 112 screwed into the bolts 114) Abut. For this reason, even when the claw 112 is closed in the direction of arrow C (2), the extrusion unit 200 is placed in the hollow portion of the parison P so that the extrusion unit 200 maintains the hollow cylindrical shape of the parison P. It is possible to maintain the distance D between the air flow channels being circulated. Even when it is necessary to change the distance D due to the shape of the parison P, the distance D can be easily changed by adjusting the position of the bolt 114 of the restricting member.

The rotation mechanism that rotates the chuck 110 uses the rotational force transmitted from the rotation servomotor 1130 by a power transmission member such as a speed reducer, a gear, and a chain in order to rotate the three chucks 110 by one rotation servomotor 1130. A gear box 1132 for receiving and rotating the pair of claws 112 of the chuck 110 is provided.
Next, the rotation angle and rotation end position of the rotation mechanism will be described with reference to FIG. Here, the target rotation angle (twist angle in the bottle B after blow molding) is set to 300 °. As described above, the blow molding unit 300 blow-molds the parison P released from being held by the chuck 110. In this case, depending on the dimensions such as the size of the parison P, the rotation angle, the viscosity of the molding material, etc., the parison released from the chuck 110 until the parison is pinched by the mold 310 (see below) The twist may return at time T (8) to time T (12) in the timing chart of FIG. Corresponding to such a case, the chuck unit 100 is released from the predetermined angle at which the parison P is rotated by the chuck unit 100 at the twist angle in the molded product after blow molding (the target rotation angle is 300 ° in FIG. 6). The angle (the rotation angle is 315 ° in FIG. 6) added to the angle corresponding to the angle (the over rotation angle is 15 ° in FIG. 6) that returns until the parison P is sandwiched between the molds 310.

  Therefore, the claw 112 is closed in the C (1) direction at the position (rotation start angle) of the claw 112 shown in FIG. 6A, and the parison P is sandwiched as shown in FIG. The chuck 110 is rotated in the direction indicated by the arrow in FIG. 6B while being lowered in the direction indicated by the arrow Z (2) in correspondence (synchronized) with the extrusion speed. As shown in FIG. 6B, when the parison P is sandwiched and the parison P is pushed by a predetermined length, the claw 112 is rotated to the position (rotation end angle) shown in FIG. 6C. Set the speed. That is, until the state shown in FIG. 6B is changed to the state shown in FIG. 6C (until the time when the parison P is pushed by a predetermined length), the chuck 110 is moved in the direction indicated by the arrow Z (2). 6 (B), while being lowered corresponding to (synchronized) with the extrusion speed of FIG. 6, it is rotated by the rotation angle (315 °) of FIG. 6 (C).

Then, at the position of the claw 112 shown in FIG. 6C (the position of the rotation end angle rotated by the rotation angle of 315 °), the claw 112 is opened in the C (2) direction, as shown in FIG. 6D. Release the parison P.
As described above, when the chuck 110 holds the outer cylindrical surface of the lower end portion of the parison P between the pair of claws 112 and releases the pinching, the parison P touches the outside air temperature, and the temperature of the parison P decreases. The lower end of the parison P sandwiched between the chucks 110 is deformed and does not return to the original cylindrical shape, but is deformed to be a substantially flat plane (however, as shown in FIG. Is not collapsed) and does not return to the cylindrical shape. In particular, depending on the specifications such as the viscosity of the molding material of the parison P and the ambient temperature of the blow molding apparatus 10, it is greatly deformed to form a substantially flat plane and does not return to the original cylindrical shape. When the pinching by the claw 112 is released from the state shown in FIG. 6C, the parison P returns to the angle corresponding to the over-rotation angle that is returned until the parison P is pinched by the mold 310.

Then, as shown in FIGS. 6D and 6E, the chuck 110 is positioned at a position where the substantially flat plane in the state where the twist is returned is substantially parallel to the plane including the mating surface of the mold 310. The rotation is stopped.
That is, about the twist (rotation) of the parison P by the chuck unit 100,
(1) The rotation angle (the absolute value thereof) is the twist angle (target rotation angle 300 ° in FIG. 6) in the molded product after blow molding, and the parison P released from the chuck 110 is sandwiched by the mold 310. An angle (an angle of rotation of 315 ° in FIG. 6) that is added by an angle corresponding to an angle that returns until the angle is reached (in FIG. 6, an over-rotation angle of 15 °),
(2) The rotation end angle is a substantially flat plane at the lower end of the parison P when the twist is restored before the parison P is sandwiched between the molds 310 (in FIG. 6, the rotation angle is returned by 15 °). Is a position substantially parallel to a plane including the mating surface of the mold 310,
As described above, based on specifications such as the shape and size of the parison P, the rotation angle, the viscosity of the molding material, and the like (by trial and error in some cases), the control parameters (rotation start) of the rotation servomotor 1130 of the chuck unit 100 The angle, rotation end angle, rotation time (= fall time), rotation start timing, rotation end timing, etc.) are set as appropriate.

The rotation direction is not limited to the counterclockwise direction shown in FIG.
-Extrusion unit This extrusion unit 200 is a unit suitably applied to a general direct blow molding apparatus, and heats and melts a molding material to extrude the parison P while maintaining a hollow cylindrical shape. As described above, what is characteristic is that one or more slits (grooves) are provided in the core of the die head 220 containing the die and the core in order to apply a pattern to the inner surface of the bottle B that is a molded product. It is a point. By providing slits in the core in this way, one or more convex portions G are formed on the inner surface of the inner cylindrical surface of the parison P corresponding to the slit portions provided in the core, and in portions other than the slits provided in the core. Correspondingly, one or more vertical grooves H (concave portions) are formed on the inner surface of the inner cylindrical surface of the parison P.

As described above, the extrusion unit 200 basically does not move except that the die head 220 moves and retracts in the Z direction when the cutter unit 240 operates.
Blow molding unit This blow molding unit 300 is a unit that is suitably applied to a general direct blow molding device, and a parison P in which a molding material is heated and melted is sandwiched between molds 310, and the mold 310 is A hollow article is formed by blowing air into the sandwiched parison P. The mold 310 is moved in the directions indicated by arrows X (3) and X (4) by the mold horizontal movement servo motor 1310 on the slide base 320. Further, the mold 310 can be opened and closed in the directions indicated by arrows Y (3) and Y (4), and hydraulic pressure or the like is used for the opening and closing.

  The mold 310 is moved in the direction of arrow X (4) to the sandwiching position (receiving position) of the parison P in the state opened in the direction of arrow Y (4), and the arrow Y is in the state of sandwiching the parison P. (3) Closed in the direction (the cutter unit 240 is operated before the mold 310 moves in the direction of the arrow X (3) at this time), and the blow position of the parison P is closed in the direction of the arrow Y (3). It moves in the direction of arrow X (3) up to (molding position). When blow molding is finished, the mold 310 is opened in the direction indicated by the arrow Y (3) in order to take out the bottle B after blow molding.

  When the mold 310 sandwiching the parison P moves in the arrow X (3) direction and arrives at the blow position (molding position), the blow head 330 moves down in the arrow Z (6) direction, The tip is inserted into the upper end of the parison P, and air is blown into the parison P sandwiched between the molds 310 to be blow-molded. When blow molding is completed, the mold 310 opens in the direction indicated by the arrow Y (3), and the blow head 330 whose tip is inserted into the upper end of the bottle B is raised in the direction indicated by the arrow Z (5). At this time, the outer periphery of the tip of the blow head 330 is attached and held on the inner periphery of the upper end of the bottle B (more specifically, the inner periphery of the burr part). For this reason, as the blow head 330 rises, the bottle B rises in the direction indicated by the arrow Z (5), and the shoulder portion of the bottle B comes into contact with the fixture 340 that does not move in the vertical direction in the middle (bottle B is more than that). Since the blow head 330 continues to rise further, the bottle B freely falls and the bottle B is detached from the blow head 330.

[Control block]
The blow molding apparatus 10 having such a configuration is controlled by the arithmetic unit 1000. Various instruments to be described later including the arithmetic unit 1000 are housed in a control panel or an operation panel. On the surface of the control panel or operation panel, a touch panel (configured by a touch panel input unit 1060 and a touch panel display driver 1090 in addition to the touch panel itself, for example) and an emergency stop push button switch 1070 are provided, and Patlite (registered trademark) or the like is provided. An indicator light 1080 is provided.

  More specifically, the control block of the blow molding apparatus 10 will be described with reference to FIG. In the control block diagram shown in FIG. 7, for example, a mode including a servo motor (including a motor drive driver) is shown. However, even if such a servo motor is not actually provided, this blow molding is performed. It suffices if the device 10 is configured in another manner so as to realize a desired operation. As such another mode, a mode in which a desired operation is realized by operating an air device, not a motor, by a solenoid valve is conceivable.

  As shown in FIG. 7, the control block of this blow molding apparatus 10 receives an input signal (such as a parison detection signal from a sensor) input from various input devices according to a program and parameters stored in advance and performs arithmetic processing. An arithmetic unit 1000 including a CPU 1010, a memory 1020, a timer 1030, and a counter 1040 that execute and output various output signals (control signals) to various output devices, various input devices connected to the arithmetic unit 1000, and various types It consists of output devices.

  As an output device, for example, there are a horizontal movement servo motor 1110, a vertical movement servo motor 1120, a rotation servo motor 1130, a chuck air cylinder 1140 of the chuck unit 100, an extrusion unit controller 1200 of the extrusion unit 200, and a blow molding unit. There are 300 mold horizontal movement servo motors 1310, mold opening / closing (hydraulic) equipment 1320, blow head vertical movement servo motor 1330, air blow equipment 1340, cutter horizontal plane moving air equipment 1350, and cutter temperature controller 1360.

  In the control block in FIG. 7, it is described that the arithmetic unit 1000 directly controls the servo motor. However, the present invention is not limited to this. In general, the arithmetic unit 1000 is connected via a servo controller. Control the servo motor. Moreover, the extrusion unit controller 1200 shown in FIG. 7 is the same as or equivalent to the one that controls the extrusion unit of a general blow molding apparatus.

  The CPU 1010 that has received the start command signal in a state where the parison P is stably extruded from the extrusion unit 200 controls the blow molding apparatus 10 as follows, for example. In the description of this case, reference is mainly made to the timing chart of FIG. Note that the time axis, which is the horizontal axis of the timing chart, is set as appropriate, and is not limited to this time axis (particularly, the relative value of the time interval), from T (0) to T (24). By substituting the actual time, a timing chart representing the actual operation is obtained. That is, for example, the delay time in this timing chart is greatly represented, and if this is the actual delay time (about 100 msec), it means that the actual timing chart is different from the timing chart of FIG. .

<Step S (1)>
The CPU 1010 that has received the start command (start command based on the operation of the operator) in a state where the parison P is stably pushed out from the extrusion unit 200, from the sensor that has detected the parison P pushed down from the die head 220 and detected. The detection signal is received.
<Step S (2)>
When a delay time elapses until the parison P descends from the position of the sensor that detects the parison P to a position where it can be clamped by the chuck 110 (more specifically, the claw 112) of the chuck unit 100, the CPU 1010 causes the chuck air cylinder of the chuck unit 100 to move. 1140 is instructed to close claw 112 opened in the direction of arrow C (2) in the direction of arrow C (1).

<Step S (3)>
The CPU 1010 that has detected that the claw 112 is closed in the direction of arrow C (1) causes the vertical movement servomotor 1120 of the chuck unit 100 to synchronize (synchronize) with the pushing speed of the parison P from the gripping position toward the opening position. And instructing the rotary servo motor 1130 of the chuck unit 100 to rotate from the rotation start position toward the rotation end position.

<Step S (4)>
The CPU 1010 that has detected that the claw 112 of the chuck unit 100 has descended in the direction of the arrow Z (2) and reached the open position and that the rotation mechanism of the chuck unit 100 has rotated to the rotation end angle is The vertical movement servo motor 1120 and the rotary servo motor are instructed to stop, and the claw 112 closed in the arrow C (1) direction on the chuck air cylinder 1140 of the chuck unit 100 is moved in the arrow C (2) direction. Instruct to open.

<Step S (5)>
The CPU 1010 that has detected that the claw 112 has opened in the direction of arrow C (2) instructs the vertical movement servo motor 1120 of the chuck unit 100 to descend in the direction of arrow Z (2) from the open position to the lower retracted position. To do.
<Step S (6)>
The CPU 1010 that has detected that the claw 112 of the chuck unit 100 has descended in the direction of the arrow Z (2) and reached the lower retracted position instructs the vertical movement servo motor 1120 of the chuck unit 100 to stop, and Instructs the horizontal movement servo motor 1110 of the unit 100 to move in the direction of the arrow X (2) from the operating position to the left retracted position.

<Steps S (7) to S (9)>
The CPU 1010 that has detected that the claw 112 of the chuck unit 100 has moved in the direction of the arrow X (2) and has reached the left retracted position instructs the horizontal movement servo motor 1110 of the chuck unit 100 to stop, The mold opening / closing (hydraulic) device 1320 of the molding unit 300 is instructed to move the mold 310 in the arrow Y (4) direction so as to be separated from each other (S (7)). The signal output in S (7) becomes an interlock signal from the chuck unit 100 to the blow molding unit 300, and the blow molding unit 300 that has received this interlock signal can start moving in the horizontal direction. Become.

  At this timing, that is, when the CPU 1010 detects that the claw 112 of the chuck unit 100 has moved in the direction of the arrow X (2) and has reached the left retracted position, the CPU 1010 detects the rotation end position at the rotation servomotor 1130 of the chuck unit 100. Is instructed to reversely rotate toward the rotation start position (S (8)), and the vertical movement servomotor 1120 of the chuck unit 100 is raised in the direction of arrow Z (1) from the lower retracted position to the gripping position. (S (9)).

<Steps S (10) to S (11)>
The CPU 1010 that detects that the claw 112 of the chuck unit 100 has moved up in the arrow Z (1) direction and has reached the gripping position instructs the vertically moving servo motor 1120 of the chuck unit 100 to stop (S ( 10)), and waits for reception of the interlock signal from the blow molding unit 300 received in S (16).

  The CPU 1010 that has detected that the reverse rotation has been completed and the claw 112 has reached the rotation start position instructs the rotary servo motor 1130 to stop (S (11)), and the blow molding received at S (16). Wait for reception of an interlock signal from the unit 300. The signal output in S (16) is an interlock signal from the blow molding unit 300 to the chuck unit 100, and the chuck unit 100 that has received this signal can start moving in the horizontal direction. .

<Step S (12)>
The CPU 1010 that has detected that the molds 310 of the blow molding unit 300 are separated from each other instructs the mold horizontal movement servo motor 1310 to move from the molding position to the receiving position in the direction of the arrow X (4).
<Step S (13)>
The CPU 1010 that has detected that the mold 310 of the blow molding unit 300 has moved in the direction of the arrow X (4) and has reached the receiving position instructs the mold horizontal movement servo motor 1310 to stop, and the mold. Instructs the opening / closing (hydraulic) device 1320 to move the mold 310 in the direction of arrow Y (3) so as to approach each other.

<Step S (14)>
CPU1010 which detected that the metal mold | die 310 of the blow molding unit 300 approached mutually and the mating surface contact | abutted outputs an operation command to the cutter unit 240. FIG. When the operation command is received, the die head 220 of the extrusion unit 200 is retracted upward from the origin position in the Z direction, and the linear heat cutter moves in the horizontal plane by the moving air device 1350 in the cutter horizontal plane of the cutter unit 240. Then, the parison P sandwiched between the molds 310 is cut, and after the operation of the cutter unit 240 is completed, the die head 220 moves downward in the Z direction and returns to the origin position.

<Step S (15)>
The CPU 1010 that has detected that the operation of the cutter unit 240 has been completed instructs the mold horizontal movement servo motor 1310 to move from the receiving position to the molding position in the direction indicated by the arrow X (3).
<Steps S (16) to S (17)>
The CPU 1010 that has detected that the mold 310 of the blow molding unit 300 has moved in the direction of the arrow X (3) and has reached the molding position instructs the mold horizontal movement servo motor 1310 to stop and also the chuck unit. 100 horizontal movement servo motors 1110 are instructed to move in the direction of arrow X (1) from the left retracted position to the operating position (S (16)), and the blow head vertical movement servo motor 1330 of the blow molding unit 300 is retracted upward. It is instructed to descend from the position to the blow position in the direction of arrow Z (6) (S (17)).

The CPU 1010 that detects that the chuck 110 of the chuck unit 100 has moved in the direction of arrow X (1) by the instruction of S (16) and has reached the operating position is a horizontal movement servo motor. 1110 is instructed to stop.
<Step S (18)>
The CPU 1010 that has detected that the blow head 330 of the blow molding unit 300 has descended in the direction of arrow Z (6) and has reached the blow position instructs the blow head vertical movement servo motor 1330 to stop and blow molding. The air blow device 1340 of the unit 300 is instructed to blow blow air from the blow head 330 into the parison P.

<Step S (19)>
The CPU 1010 that has detected that the blow molding time has elapsed instructs the air blow device 1340 of the blow molding unit 300 to stop the discharge of the blow air, and also sends the die opening / closing (hydraulic) device 1320 of the blow molding unit 300 to the mold. Instruct to move 310 in the direction of arrow Y (4) so as to be separated from each other.

<Step S (20)>
The CPU 1010 that has detected that the molds 310 of the blow molding unit 300 are separated from each other causes the blow head vertical movement servomotor 1330 of the blow molding unit 300 to move the blow head 330 from the blow position to the upper retracted position in the arrow Z (5) direction. To ascend to.

<Step S (21)>
While the blow head 330 is raised, the bottle B rises to an arrow Z (5) with the rise of the blow head 330, and the shoulder B comes into contact with the fixture 340 that does not move in the vertical direction and the bottle B falls freely. The CPU 1010 that has detected the instruction instructs the mold opening / closing (hydraulic) device 1320 to move the mold 310 in the arrow Y (3) direction so as to approach each other.

[Operation]
Operation | movement of the blow molding apparatus 10 provided with the above structures (a program structure is included) is demonstrated. Also in the description of the operation, the timing chart in FIG. 8 is mainly referred to.
An operator causes the blow molding apparatus 10 to start blow molding (giving a start command signal) in a state where the parison P shown in FIG. 9A is stably extruded from the extrusion unit 200.

At time T (0), the sensor detects the parison P that is pushed out of the dice head 220 and descends (S (1)). The parison P at this time is in the state shown in FIG.
While the delay time has elapsed from time T (0) to time T (1), the parison P descends to a position where it can be clamped by the chuck 110 (more specifically, the claw 112), and at time T (1) The claw 112 of the chuck 110 of the chuck unit 100 opened in the direction indicated by C (2) is closed in the direction indicated by arrow C (1). Thereby, the state shown in FIG. 5 (A) is changed to the state shown in FIG. 5 (B), and the claw 112 holds the parison P therebetween.

During the period from time T (2) to time T (3), the claw 112 of the chuck 110 of the chuck unit 100 is closed and the lower end portion of the parison P is clamped so as to correspond (synchronize) with the extrusion speed of the parison P. Thus, the chuck 110 rotates while descending. At this time, the state shown in FIG. 6A is changed to the state shown in FIG. 6C through the state shown in FIG. 6B.
At time T (4), the pawl 112 of the chuck 110 of the chuck unit 100 is opened and the holding of the parison P is released. Transition from the state shown in FIG. 6C to the state shown in FIG. In addition, from time T (4) when the claw 112 of the chuck 110 of the chuck unit 100 is opened and the holding of the parison P is released, until time T (12) when the mold 310 of the blow molding unit 300 holds the parison P, Since the lower end portion of the parison P is not sandwiched, the twist returns by the over-rotation angle of 15 ° shown in FIG. The parison P at this time is in the state shown in FIG.

During the time from time T (5) to time T (6), the chuck 110 of the chuck unit 100 is lowered from the open position to the lower retracted position. Thereby, the chuck 110 and the parison P are completely separated from each other, and the chuck 110 of the chuck unit 100 can be moved horizontally.
In a time period from time T (7) to time T (8), the chuck 110 of the chuck unit 100 moves from the operating position to the left retracted position. Thereby, the chuck unit 100 is completely retracted from the extrusion unit 200, and the mold 310 of the blow molding unit 300 can be moved horizontally.

  At time T (9), the closed mold 310 is opened, and during the period from time T (10) to time T (11), the mold 310 of the blow molding unit 300 moves from the molding position to the receiving position. . Thereby, it becomes possible to receive the parison P in a state where the mold 310 of the blow molding unit 300 is suspended (hanging) from the die head 220 of the extrusion unit 200. At this time, the parison P and the mold 310 of the blow molding unit 300 are in the state shown in FIG. 6 (D) and FIG. 6 (E).

  At time T (12), the opened mold 310 is closed, and the cutter unit 240 is operated during a period from time T (13) to time T (14). At this time, the die head 220 of the extrusion unit 200 is retracted upward from the origin position in the Z direction, the linear heat cutter moves in the horizontal plane and cuts the parison P sandwiched between the molds 310, After the operation of the cutter unit 240 is completed, the die head 220 moves downward in the Z direction and returns to the home position. As a result, the parison P sandwiched between the molds 310 and the parison P continuously extruded from the die head 220 of the extrusion unit 200 are separated, and the mold 310 of the blow molding unit 300 can be moved horizontally. Become.

  During a period from time T (15) to time T (16), the mold 310 of the blow molding unit 300 moves from the molding position to the blow position. As a result, the blow head 330 of the blow molding unit 300 is lowered into the parison P sandwiched between the molds 310 of the blow molding unit 300 and the nozzle at the tip of the blow head 330 can be inserted into the parison P.

During a period from time T (17) to time T (18), the blow head 330 of the blow molding unit 300 is lowered from the upper retracted position to the blow position, and the nozzle at the tip of the blow head 330 is inserted into the parison P. .
During the time (blow molding time) from time T (19) to time T (20), blow air is blown from the nozzle at the tip of the blow head 330 inserted into the parison P into the parison P, and the parison P expands. .

  At time T (21), the closed mold 310 is opened, and during the time from time T (22) to time T (23), the blow head 330 of the extrusion unit 200 rises from the blow position to the upper retracted position. . When the bottle B freely falls during the raising of the blow head 330, at time T (24), the opened mold 310 is closed, one cycle time is completed, and the state of all devices is T (0). ).

In this state, the operator takes out the bottle B manufactured by the blow molding apparatus 10. The bottle B at this time is in the state shown in FIG.
As described above, according to the blow molding apparatus 10 according to the present embodiment, a blow molding method can be realized, and a blow molding in which a spiral pattern is applied to the inner surface of a side surface at a low cost with a simple manufacturing apparatus. Product can be manufactured.
<Modification>
Hereinafter, a blow molding apparatus according to a modification of the present invention will be described. The blow molding apparatus according to the present modification has the above-described blow molding except that it includes a die head 500 different from the die head 220 of the blow molding apparatus 10 described above (specifically, the die head 400 shown in FIG. 10). The same operation is realized with the same configuration as the apparatus 10. Therefore, description of the same configuration and the same operation will not be repeated here.

  Formed so as to protrude from at least one of the inner peripheral surface and the outer peripheral surface of the substantially hollow cylindrical base layer in which the first molding material is heated and melted by the die head 500 provided in the blow molding apparatus according to this modification. At the same time, the parison P having a non-annular cross-sectional shape including one or more convex portions G formed along the pushing direction of the parison P is pushed downward from the die head 500. What is characteristic is that, unlike the blow molding apparatus 10 described above, the convex portion G is a second molding material in which the resin passage in the die head 500 is different from the first molding material forming the base layer. It is a point that is formed.

  More specifically, the die head 500 includes a housing and two or more mandrels. The first resin passage through which the first heat-melted molding material flows and the second heat-melted molding material flow. Including the second resin passage, and the first resin passage and the second resin passage do not merge inside the die head 500. In this modification, since there are two types of molding materials, it is assumed that there are two mandrels. However, the number of mandrels is appropriately changed according to the number of types of molding materials.

  Here, the first molding material and the second molding material may be the same or different, but the first molding material and the second molding material are different from each other. It is particularly preferable in terms of the design of the bottle B molded by the blow molding apparatus according to this modification to make the color of the second molding material different from the color of the second molding material. In the case where the first molding material and the second molding material are different, it is also preferable to form an adhesive layer on the contact surface between the first molding material and the second molding material.

Such a die head 500 is not limited, but as an example, a die head 500 shown in FIG. 11 is employed.
11A is a partial cross-sectional view of the die head 500, FIG. 11B is a partial bottom view of the die head 500, and FIG. 11C is a partially enlarged view of FIG. 11B. The die head 500 will be described. In FIG. 11, as in FIG. 10, the resin supply mechanism, such as an extruder, a plunger, and an accumulator, are not shown because they are known techniques.

In general, the die head 500 has a mandrel (specifically, a base layer mandrel 521 which is a first mandrel disposed on the outer peripheral side and a second mandrel disposed on the inner peripheral side thereof on the central axis side. It comprises a die housing 510 in which a decoration mandrel 522) is inserted and a die (die) 580 provided therebelow. A die head 500 shown in FIG. 11 is a so-called side feed system that supplies the first molding material and the second molding material that are heated and melted from one side of the die head 500, and is a resin supply mechanism. The first molding material and the second molding material in a high-temperature molten state pressed by
(1) a first resin supply port 531 and a second resin supply port 532;
(2) a first manifold 541 and a second manifold 542 connected to the first resin supply port 531 and the second resin supply port 532, respectively.
(3) a first resin passage 551A and a second resin passage 552A connected to the first manifold 541 and the second manifold 542, respectively.
(4) a first resin passage 551B and a second resin passage 552B respectively connected to the first resin passage 551A and the second resin passage 552A;
Are sequentially supplied.

The first manifold 541 and the second manifold 542 are branched halfway to the left and right in the circumferential direction of the first mandrel (base layer mandrel 521) and the second mandrel (decorating portion mandrel 522), respectively. A semicircular cross-sectional shape that curves in the extrusion direction with a predetermined curvature while gradually decreasing the area at a predetermined ratio is provided.
By the first manifold 541, the first molding material heated and melted is distributed and supplied to the annular first resin passage 551A and the annular first resin passage 551B, which are located downstream. A uniform annular flow is formed in the resin passage 551A and the annular first resin passage 551B (discharged from an annular space passage 561 described later), and a base layer is formed of the first molding material.

  Further, the second manifold 542 distributes and supplies the second molding material heated and melted to the annular second resin passage 552A and the annular second resin passage 552B, which are located downstream, and these second molding materials are supplied. A uniform annular flow is formed in the second resin passage 552A and the annular second resin passage 552B (discharged from a discharge passage 562 described later), and a decorative portion (convex portion) G is formed by the second molding material. Is done.

  More specifically, the first molding material heated and melted is connected to the annular first resin passage 551A provided between the die housing 510 and the base layer mandrel 521, and to the first resin passage 551A. Is formed between the die 580 and the base layer mandrel 521 or through the annular first resin passage 551B provided in the die 580 and discharged from the lowermost annular space passage 561 to form the base layer of the parison P. To do. Further, the second molding material heated and melted is connected to the annular second resin passage 552A provided between the base layer mandrel 521 and the decorative portion mandrel 522, and to the second resin passage 552A. Through the second annular resin passage 552B provided between the die 580 and the decorative portion mandrel 522, and discharged from the discharge passages 562 provided in a radially scattered manner at the lowermost end, and the parison P The decorative part (convex part) G is formed.

Here, a core 570 is provided at the lowermost end of the dice head 500, and the core 570 is connected to a paricon (parison control) rod 590 that penetrates the decorative portion mandrel 522. It is advanced and retracted, and the gap (gap) of the annular space passage 561 can be adjusted to control the wall thickness of the parison P.
In the present invention, a discharge passage 562 is formed by radially scattered holes on the outer periphery of the core 570, and a convex portion G (FIG. 9) is formed on the inner peripheral surface of the parison P corresponding to the portion of the discharge passage 562. (See (A)) is formed of a second molding material in which the resin passage in the die head 500 is different from the first molding material constituting the base layer.

  As described above, in the die head 500, the first resin passage (the first resin passages 551A and 551B and the annular space passage 561) through which the first heat-melted molding material flows, and the heat-melted first resin passage are provided. Second resin passages (second resin passages 552A, 552B and discharge passages 562) through which the two molding materials flow, and these first resin passages and second resin passages are formed inside the die head 500. The feature is that they do not merge.

  In the parison P extruded by the die head 500 having such a configuration, a base layer constituting the main body of the bottle B to be molded, and a decorative portion (convex portion) G for decorating the molded bottle B, However, the resin passages are completely separated from each other inside the die head 500. For this reason, the base layer constituting the main body of the bottle B to be molded includes only the first molding material formulated so as to realize the function required for the main body of the bottle B, and includes the second molding material. Absent. For this reason, in the above-described blow molding process, the main body of the bottle B is formed by the base layer composed only of the first molding material, so that the main body of the bottle B is reliably blow-molded, resulting in a molding error or poor strength. Etc. can be avoided. On the other hand, the decorative portion formed on the inner peripheral surface of the bottle B to be molded includes only the second molding material blended so as to realize the decorating function, and does not include the first molding material. For this reason, in the above-mentioned blow molding process, only the base layer composed only of the first molding material is expanded to form the main body of the bottle B, and the decorative portion is not expanded (compared to the base layer). Even if blow molding, the thickness of the decorative part is uniformly formed (because the thick part of bottle B is formed into a thick decoration and the thin part of bottle B is not formed into a thin decoration. ) The decoration can be improved.

  Here, in the blow molding apparatus according to the present modification, the twisting step of gripping and twisting the parison P pushed out from the extrusion unit by the chuck unit 100 is not always essential. That is, when the twisting step is executed, a different pattern or a spiral pattern of the same color is applied to at least one of the inner surface (inner peripheral surface) and the outer surface (outer peripheral surface) of the side surface of the bottle B. If the twisted step is not performed, at least one of the inner surface (inner peripheral surface) and the outer surface (outer peripheral surface) of the side surface (peripheral surface) is different in color or the same A blow-molded product having a linear color pattern can be produced.

As described above, according to the blow molding apparatus according to this modification, the blow molding method can be realized, and the inner surface (inner peripheral surface) and the outer surface (outer peripheral surface) of the side surface can be realized with a simple manufacturing apparatus and at a low manufacturing cost. It is possible to manufacture a blow molded article in which a linear pattern or a spiral pattern of different colors or the same color is applied to at least one surface (peripheral surface).
<Dice head applicable to modification>
Furthermore, with reference to FIG. 12, the die head applicable to the blow molding apparatus which concerns on this modification is demonstrated. 12 (A) to 12 (D) are partial enlarged views of the bottom view of the die head corresponding to FIG. 11 (C). In the dice head shown in FIGS. 12 (A) to 12 (D), the convex portion, which is a decorative portion provided on at least one surface (peripheral surface) of the inner peripheral surface and the outer peripheral surface of the parison P, The second molding material in which the resin passage in the die head is different from the first molding material constituting the base layer (may be the same as the first molding material or different from the first molding material) It is the same in that it is formed.

  A dice head 600 shown in FIG. 12 (A) is an example of a dice head for extruding a parison P having one or more decorative portions (convex portions) on the outer peripheral surface of the base layer. The core 670 is not provided with discharge passages that are radially scattered holes, and discharge passages 662 that are radially scattered holes are formed in the die 680, and the parison P corresponds to the portion of the discharge passage 662. The convex portion G is formed on the outer cylinder surface of the second molding material having a resin passage in the die head 600 different from that of the first molding material constituting the base layer.

A dice head 700 shown in FIG. 12B is an example of a dice head for extruding a parison P including one or more decorative portions (convex portions) on the inner and outer peripheral surfaces of the base layer. The core 770 includes discharge passages 762A (corresponding to the above-described discharge passages 562) that are radially scattered holes, and the die 780 corresponds to discharge passages 762B (corresponding to the above-described discharge passages 662) that are radially scattered holes. ), And a convex portion G is formed on the inner cylindrical surface of the parison P corresponding to the portion of the discharge passage 762A, and a convex portion is formed on the outer cylindrical surface of the parison P corresponding to the portion of the discharge passage 762B. The first molding material is formed of a second molding material having a resin passage different from that of the first molding material. In this case, the same second molding material may be supplied to the discharge passage 762A and the discharge passage 762B, or the second molding material may be supplied to one of the discharge passage 762A and the discharge passage 762B. On the other hand, a third molding material different from the second molding material may be supplied.

  In the die head 800 shown in FIG. 12 (C), holes, which are discharge passages provided in the die head 700 shown in FIG. 12 (B), are provided at the same radial positions on the inner periphery and outer periphery of the parison P. It is characterized in that it is provided at different angular positions. The dice 780 includes discharge passages 862B (corresponding to the discharge passages 662 described above) that are radially scattered holes, and the cores 870 are discharge passages that are holes scattered at different angular positions radially from the discharge passages 862B. 862A.

A dice head 800 shown in FIG. 12D includes a dice head 500 shown in FIG. 11C, a dice head 600 shown in FIG. 12A, and a discharge passage in the dice head 700 shown in FIG. The positions where all the points are line-symmetrical and / or point-symmetrical are not symmetrical but point-symmetrical.
By using such a dice head shown in FIG. 12, at least one surface (peripheral surface) of the inner surface (inner peripheral surface) and outer surface (outer peripheral surface) of the side surface is a linear pattern of different colors or the same color. Alternatively, it is possible to produce a blow molded product having a spiral complicated pattern.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  The present invention provides different colors or the same color for at least one of the inner surface (inner peripheral surface) and the outer surface (outer peripheral surface) of the side surface at a low manufacturing cost with a simple manufacturing apparatus in direct blow molding. The present invention can be suitably used for a technique for producing a molded product having a linear pattern or a spiral pattern.

10 Blow Molding Device 100 Chuck Unit 200 Extrusion Unit 300 Blow Molding Unit 1000 Arithmetic Unit

Claims (8)

A molding apparatus for producing a synthetic resin molded product by a blow molding method,
1 is formed so as to protrude from at least one of the inner peripheral surface and the outer peripheral surface of the substantially hollow cylindrical base layer obtained by heating and melting the first molding material, and is formed along the direction in which the parison is extruded. An extruding mechanism for extruding a parison having a non-annular cross-sectional shape having the above convex portions downward from a die head;
A blow molding mechanism for sandwiching the extruded parison with a mold and blow molding,
The convex portion is formed of a second molding material in which a resin passage in the die head is different from the first molding material forming the base layer ,
The molding apparatus further includes a twisting mechanism for gripping and twisting the parison extruded from the extrusion mechanism,
The blow molding mechanism is blow molded by sandwiching a parison twisted by the twist mechanism with a mold,
The twisting mechanism is
Gripping means for gripping the end of the parison extruded from the extrusion mechanism;
Rotation means for rotating the gripping means gripping the end of the parison by a predetermined angle, with an axis parallel to the direction of pushing out the parison as a rotation axis,
The blow molding mechanism blow-molds the parison released from gripping by the gripping means,
The predetermined angle is an angle obtained by adding to the twist angle in the molded product after the blow molding by an amount corresponding to the angle corresponding to the angle at which the parison that has been released from gripping is sandwiched between the molds. Blow molding equipment. The die head includes a housing and two or more mandrels. The first resin passage through which the first melted and melted molding material flows, and the second flow through which the second melted and melted molding material flows. A resin passage,
The first resin passage and the second resin passage do not merge inside the die head;
The blow molding apparatus according to claim 1.   The blow molding apparatus according to claim 1 or 2, wherein a color of the first molding material is different from a color of the second molding material. The extrusion mechanism continuously extrudes the parison,
The twisting mechanism further comprises a moving means for moving the gripping means holding the end portion of the parison in correspondence with the extrusion speed of the parison downwardly along the rotation axis direction, according to claim 1 wherein Item 4. The blow molding apparatus according to any one of Items 3 to 3 . The extrusion mechanism extrudes the parison while circulating air through the hollow portion of the parison in order to maintain the substantially hollow cylindrical shape of the parison,
The blow molding apparatus according to claim 1 , wherein the gripping unit grips an end portion of the parison so as not to hinder the air flow. Before SL gripping means clamp the outer cylindrical surface of the end portion of the parison by a pair of chucks,
The mold is a mold divided into at least two facing facing surfaces that are spaced apart from each other,
The rotating means moves the end of the parison so that a substantially flat plane formed by being held by the chuck in the parison with the chuck released is substantially parallel to a plane including the mating surface. stopping the rotation of the gripped gripping means, the blow molding apparatus according to any one of claims 1 to 5. A molding method for producing a molded product made of synthetic resin by a blow molding method,
1 is formed so as to protrude from at least one of the inner peripheral surface and the outer peripheral surface of the substantially hollow cylindrical base layer obtained by heating and melting the first molding material, and is formed along the direction in which the parison is extruded. Extrusion step for extruding the non-annular cross-sectional parison with the convex portions downward from the die head;
A molding step of sandwiching the extruded parison with a mold and blow molding,
The convex portion is formed of a second molding material in which a resin passage in the die head is different from the first molding material forming the base layer,
The molding method further includes a twisting step of gripping and twisting the parison extruded in the extrusion step,
In the molding step, the parison twisted by the twisting step is sandwiched between molds and blow molded,
The twisting step includes
A gripping step of gripping an end of the parison extruded in the extrusion step;
A rotation step of rotating by a predetermined angle in a gripping step of gripping the end of the parison, with an axis parallel to the direction of extrusion of the parison as a rotation axis,
The molding step blow-molds the parison released from gripping by the gripping step,
The predetermined angle is an angle obtained by adding to the twist angle in the molded product after the blow molding by an amount corresponding to the angle corresponding to the angle at which the parison that has been released from gripping is sandwiched between the molds. Blow molding method. The blow molding method according to claim 7 , wherein a color of the first molding material is different from a color of the second molding material.

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