JP2016215504A - Production method of single wall molded product - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a production method of a single wall molded product capable of forming an inner rib with designed height, and in which molding defect such as deformation does not occur.SOLUTION: There is provided a production method of a single wall molded product in which, a pair of molds are closed, and a molten resin sheet is molded along one mold cavity, and a rib formation blade is protruded from the mold, for projecting the molten resin sheet for forming a rib. A recess part is formed on the counter mold, and a tip end part of the molten resin sheet is engaged to the recess part by protruding the rib formation blade, then, the rib formation blade is retreated, and inside of a mold space which is closed, is compressed, for depositing facing inner faces of the protruded molten resin sheet, for forming the rib.SELECTED DRAWING: Figure 1b

Description

  The present invention relates to a method for producing a single wall molded body, and more particularly to a novel technique for improving molding defects of an inner rib in molding a single wall molded body having an inner rib.

  For example, so-called resin laminates are used as automotive interior materials, building materials, logistics and packaging materials, and inner ribs are used between the front and back materials to improve strength and reduce weight. There has been proposed a molded body having a hollow double-walled structure (see, for example, Patent Document 1).

  The hollow double-walled molded body has a structure in which one wall and the other wall are integrated by a rib that connects each other in the hollow portion. In blow molding, one wall and the other wall are combined with the other wall. It is manufactured by forming a rib so as to project a part of a wall until it comes into contact with one wall and connecting them integrally in a hollow portion, so-called inner rib.

  For example, in the method for producing a hollow double-wall structure disclosed in Patent Document 1, a sliding mold is inserted into a cavity between a pair of split molds having a sliding mold (rib forming blade) for forming a rib. Place the thermoplastic resin parison in the state of protruding from the surface, clamp it, press the part extruded by the sliding mold of the parison to the opposing parison, and then retreat immediately before retraction of the sliding mold In a suitable time zone until just after that, pressure fluid is introduced into the parison to form the parison into a shape along the cavity surface of a pair of molds, and then sliding while sliding the sliding mold backward The side surfaces of the walls protruded by the mold are welded together by blow pressure, thereby forming an integral rib between one wall and the other wall.

JP 2001-239576 A

  By the way, in the field of resin panels, there is a demand for further weight reduction, and development of resin panels that are lighter than the above-mentioned molded article having a hollow double wall structure is being promoted. For example, in a molded article having a hollow double wall structure, it has been studied to reduce the weight by omitting one wall surface.

  However, if the method for forming a hollow double wall structure is applied to the formation of a single-wall molded body in which one wall surface is omitted as it is, there arises a big problem that a defective molding of the inner rib occurs.

  In forming a hollow double-walled molded body, the tip of the rib is pressed against the opposite wall surface by the tip of the rib-forming blade for rib formation and fused. Therefore, even after the rib forming blade for forming the inner rib is retracted, the rib shape is maintained by the fusion and an appropriate shape can be formed.

  On the other hand, in the molding of the single wall molded body, when the inner rib is formed by protruding the tip of the rib forming blade, there is no opposite wall surface on the opposite side. It is not fixed. For this reason, the inner rib follows the return of the rib forming blade, and the tip of the rib is not held at a predetermined height, so that there is a problem that the shape of the inner rib as designed cannot be formed.

  Further, the inner rib stretched by the rib forming blade is in a molten state at this stage. If the rib forming blade is moved backward in this state and blow pressure is applied, the inner rib may be deformed.

  The present invention has been made in view of the above-described conventional situation, and it is possible to form a single-wall molded body in which the inner rib can be formed at a height as designed, and molding defects such as deformation do not occur. It aims to provide a method.

  In order to achieve the above object, a method for producing a single wall molded body of the present invention includes a method of clamping a pair of molds and shaping a molten resin sheet along one mold cavity. In a manufacturing method of a single wall molded body in which a rib is formed by projecting a rib forming blade from a mold and projecting a molten resin sheet, recesses are formed in opposing molds, and the rib forming blade is projected. Thus, the front end portion of the molten resin sheet is locked in the concave portion, and then the rib forming blade is retracted, and the inside of the mold space that is clamped is pressed to oppose the protruded molten resin sheet. The ribs are formed by welding the inner surfaces together.

  By locking the tip of the molten resin sheet to the concave portion of the opposing mold, and then retreating the rib forming blade, the rib does not follow the retreat of the rib forming blade, and the predetermined height is reached. Kept. Further, even if the rib is in a molten state, the rib is held in an upright state, and molding defects such as deformation do not occur.

  ADVANTAGE OF THE INVENTION According to this invention, it is possible to provide the manufacturing method of the single wall molded object which can form an inner rib by the height as designed, and does not generate | occur | produce shaping | molding defects, such as a deformation | transformation.

BRIEF DESCRIPTION OF THE DRAWINGS It is the schematic sectional drawing which shows the manufacturing method of the single wall molded object to which this invention is applied, and shows the braid | blade formation process for rib formation. It is a schematic sectional drawing which shows the process of latching the front-end | tip of a molten resin sheet to the recessed part of the metal mold | die which opposes. It is a schematic sectional drawing which shows the process of retracting the rib formation blade. It is a schematic sectional drawing which shows the process of applying a blow pressure. It is a schematic sectional drawing which shows the taking-out process of a single wall molded object. It is a figure which expands and shows the recessed part provided in the metal mold | die which opposes. It is a figure which expands and shows the recessed part vicinity in the process of FIG. It is a figure which expands and shows the recessed part vicinity in the process of FIG. 1b. It is a schematic perspective view of the shape | molded single wall molded object. It is a schematic sectional drawing which shows the manufacturing process when not providing a recessed part in the metal mold | die which opposes, and shows the braid | blade formation process for rib formation. It is a schematic sectional drawing which shows the process of retracting the rib formation blade. It is a schematic sectional drawing which shows the state of the rib after the rib formation blade retreats. It is a schematic sectional drawing which shows the process of applying a blow pressure. It is a schematic sectional drawing which shows the taking-out process of a single wall molded object.

  Hereinafter, an embodiment of a method for producing a single wall molded body of the present invention will be described in detail with reference to the drawings.

The single wall molded body manufactured by the manufacturing method of the present embodiment is formed by forming a single molten resin sheet into a panel shape or the like and forming ribs for reinforcement.

  The thermoplastic resin used for the molten resin sheet is not particularly limited and may be any one as long as it can be molded. For example, polyethylene resin, polypropylene resin, ethylene-acetic acid Engineering plastics such as vinyl copolymer, vinyl chloride resin, ABS resin (acrylonitrile-styrene-butadiene resin), polyamide resin, polystyrene resin, polyester resin, polycarbonate resin, and modified polyphenylene ether are suitable. A filler such as glass fiber, carbon fiber, calcium carbonate, talc, and mica can be appropriately added.

  In order to manufacture a single wall molded body, first, a molten resin sheet in a molten state extruded from a resin extrusion head is disposed between a pair of molds, and shaped along a cavity of one mold by, for example, vacuum suction. To do. The one mold has a vacuum chamber and a ventilation contact surface, and the molten resin sheet is shaped into a shape along the cavity of the mold by vacuum suction on the ventilation contact surface.

  Next, the shaped molten resin sheet is stretched by protruding a rib forming blade to form a rib. FIG. 1a shows a state in which the rib forming blade is protruded. Of the pair of molds 1, 2, the molten resin sheet 3 shaped in the cavity shape of one mold 1 is directed toward the mold 2 facing the rib forming blade 5 provided in the slide mechanism 4. Stretched. A rib is formed by the stretched portion (rib forming portion) 3a.

  The opposing mold 2 is provided with a recess 2a corresponding to the rib forming blade 5, and the rib forming blade 5 is provided at the tip of the rib forming portion 3a of the molten resin sheet 3 as shown in FIG. However, it protrudes until it bites into the recess 2a.

  FIG. 2 is an enlarged view of the shape of the recess 2 a provided in the opposing mold 2. The recessed part 2a provided in the opposing metal mold | die 2 should just be a shape which can latch the front-end | tip part of the molten resin sheet 3, for example, the opening width L1 of the opening part 2b is the largest space width of the back part of the recessed part 2a. The shape may be slightly smaller than L2 (so-called under shape). Thus, the molten resin sheet 3 that has entered the recess 2a is supported without being easily detached. If the width L1 of the opening 2b is larger than the maximum space width L2, the molten resin sheet 3 pushed into the recess 2a may be inadvertently detached. However, if the maximum space width L2 of the concave portion 2a is too large compared to the opening width L1 of the opening portion 2b, the molten resin sheet 3 pushed into the concave portion 2a is difficult to come off, so that it is within an appropriate range. preferable.

  3 and 4 correspond to the steps of FIGS. 1a and 1b, respectively, and show the vicinity of the concave portion 2a of the opposing mold 2 in an enlarged manner. By the protrusion of the rib forming blade 5, the tip of the rib forming portion 3a of the molten resin sheet 3 bites into the concave portion 2a and is held.

  When the tip of the rib forming portion 3a of the molten resin sheet 3 is bitten into the recess 2a, the rib forming blade 5 is moved backward as shown in FIG. 1c. At this time, since the tip of the rib forming portion 3a of the molten resin sheet 3 is held by the recess 2a, the rib forming portion 3 does not follow the retreat of the rib forming blade 5 and has a predetermined height. Is maintained. In addition, the molten resin sheet 3 is in a molten state at this stage and is in a state of being easily deformed, but the holding does not cause molding defects such as the rib forming portion 3a falling.

  Next, as shown in FIG. 1d, an internal pressure is applied to the space between the pair of molds 1 and 2 by applying a blow pressure, for example, and the rib forming portion 3 is pressed and integrated. By applying the blow pressure, the opposed inner surfaces 3c and 3d of the rib forming portion 3 are welded and integrated to form a rib.

  Finally, as shown in FIG. 1e, the molds 1 and 2 are opened, and a molded body in which the molten resin sheet 3 is molded into a predetermined form (form having ribs) is taken out. By making the shape of the concave portion 2a provided in the mold 2 appropriate, the tip of the rib forming portion 3a is easily detached from the concave portion 2a, and the molded body is taken out.

  As shown in FIG. 5, the single wall molded body 10 to be molded is obtained by forming a rib (rib forming portion 3 a) for reinforcement on a panel shaped by the mold 1, and the rib forming portion 3 a. Is maintained in the recess 2a of the mold 2 and is formed as designed. Moreover, molding defects such as deformation do not occur in the rib forming portion 3a.

  Next, for comparison, a case will be described in which a single-wall molded body is formed without providing the opposing mold 2 or without forming the recess 2a in the opposing mold 2. FIGS. 6 a to 6 e are diagrams showing each step when forming a single wall molded body without providing the opposing mold 2 or without forming the recess 2 a in the opposing mold 2.

  Even when a single wall molded body is formed without providing the opposing mold 2 or without forming the recess 2a in the opposing mold 2, the molten resin sheet in a molten state extruded from the resin extrusion head is vacuum-suctioned, for example. In the same manner as in the production method of the present invention, the molded resin sheet is shaped along the mold cavity, and the shaped molten resin sheet is stretched by protruding a rib forming blade to form a rib.

  That is, after the molten resin sheet 13 is shaped along the cavity of the mold 11, as shown in FIG. 6a, the rib forming blade 15 provided on the slide mechanism 14 is protruded so that the rib forming portion 13a is Enlarge. At this time, the tip of the rib forming portion 13a is not locked by the opposing mold and is in a free state.

  In this state, as shown in FIG. 6 b, the rib forming blade 15 is retracted. At this time, the rib forming portion 13 a follows the rib forming blade 15 as the rib forming blade 15 is retracted. Retract and cannot maintain the predetermined height as shown in FIG. 6c.

  Next, as shown in FIG. 6d, a blow pressure is applied, the rib forming portion 13a is welded and integrated, and the molded product is taken out as shown in FIG. 6e. However, the design value is insufficient, resulting in molding failure. Further, the rib forming portion 13a may be deformed in the steps of FIGS. 6b to 6d.

  As is clear from the comparison of the molding methods described above, in the method for producing a single wall molded body of the present invention, the rib forming portion 3a is held by the concave portion 2a provided in the opposing mold 2, so the rib height is designed. It is clearly advantageous to maintain the quality of the single-wall molded body, such as being able to be formed in the street and without deformation.

  As mentioned above, although embodiment which applied this invention has been described, this invention is not limited to this embodiment, and it cannot be overemphasized that a various change is possible in the range which does not deviate from the summary of this invention. .

DESCRIPTION OF SYMBOLS 1, 2 Mold 2a Recessed part 3 Molten resin sheet 3a Rib forming part 4 Slide mechanism 5 Rib forming blade 10 Single wall molded body

Claims (2)

A pair of molds are clamped, a molten resin sheet is shaped along one mold cavity, and a rib is formed by protruding a rib forming blade from the mold to protrude the molten resin sheet. In the method for producing a single wall molded body,
A concave portion is formed in the opposing mold, and the tip of the molten resin sheet is locked to the concave portion by causing the rib forming blade to protrude,
Thereafter, the rib forming blade is retracted and the inside of the clamped mold space is pressurized to weld the opposed inner surfaces of the molten resin sheet so as to form the rib. A method for producing a wall molded body. The method for producing a single wall molded body according to claim 1, wherein the concave portion has an under shape in which a size of a back portion is larger than a size of an opening portion.

Images