JP5587699B2 - Manufacturing method of molded products for packaging - Google Patents

Description

  The present invention relates to a molded article for packaging made of unstretched plastic and a method for producing the molded article for packaging.

  2. Description of the Related Art Molded products for packaging (containers and lids) made of unstretched plastic for packaging commodities such as foods are known. Such a molded product for packaging is produced by forming a raised part in a saddle shape by vacuum molding or pneumatic molding on a plastic sheet, cutting it leaving a margin at the peripheral edge of the part, and separating it from the sheet body Is done.

  As a result, the finished molded product for packaging has a flange formed by the above-described margin on the entire periphery of the opening edge of the saddle-shaped body, and a sharp cut surface appears on the outer periphery of this flange. Therefore, when handling the molded product for packaging, there is a risk that the hand may be cut at the cut surface.

Therefore, it is often performed to curl a flange formed at the opening edge of the molded product for packaging to form an edge winding portion so that the hand is not cut at the cut surface.
As an example, there is a method of forming an edge winding portion using a plurality of curling rolls in which spiral curling grooves are formed on a cylindrical peripheral surface as in Patent Document 1. The plurality of curling rolls are arranged in an annular shape at equal intervals.

Set the molded product for packaging in a state where the flange is introduced into the curling groove of each curling roll, and rotate the molded product for packaging along the curling groove in the axial direction while rotating each curling roll. I will move it. Since the curling groove has a narrower width in the direction of transfer of the molded product for packaging, the flange introduced into the curling groove gradually curls with the transfer, and an edge winding portion is formed.
Incidentally, by curling the flange in this manner to form the edge winding portion, the thickness of the opening edge portion is increased and the rigidity of the entire molded product is also increased.

JP 60-132732 A

  However, when curling the flange while rotating the molded product for packaging as in Patent Document 1, it is not possible to form an edge winding over the entire periphery of the opening edge unless the molded product for packaging is circular in plan view. Is possible. Therefore, the shape of the molded product that can be curled is substantially limited to a circular shape in plan view.

  Therefore, the problem to be solved by the present invention is to make it possible to form an edge winding portion at the opening edge of a molded product for packaging made of unstretched plastic having various shapes in plan view.

In order to solve the above-described problems, the method for manufacturing a molded product for packaging made of unstretched plastic according to the present invention includes the following configuration.
That is, the manufacturing method according to the invention includes a step of molding a pre-molded product for packaging made of unstretched plastic having a saddle-shaped main body and a cylindrical winding allowance provided continuously around the entire periphery of the opening edge of the saddle-shaped main body. .
Further, the method includes a step of preparing a cylindrical curling mold in which an annular curling groove extending in the circumferential direction is formed on the inner peripheral surface.
Further, the method includes a step of arranging the pre-molded product so that the saddle mold main body is inside the curling mold and the leading end of the winding margin is introduced into the curling groove of the curling mold.
Lastly, while heating the curling mold, the curling groove is slid in the axial direction so as to approach the opening edge of the saddle mold body of the pre-molded product, and the winding allowance softened by heating the curling mold is Including the step of winding toward the opening edge of the saddle-shaped body to form the edge winding portion.

  According to this method, since the edge winding portion is formed without rotating the molded product for packaging, the edge winding portion is formed not only for the circular shape in plan view but also for the molded products for packaging made of various shapes of unstretched plastic. Became possible.

(A) of the molded product for packaging of the embodiment is a perspective view, (b) is a cross-sectional view of the arrow of (a) Vertical sectional view of the manufacturing apparatus of the embodiment Vertical sectional view of the manufacturing apparatus of the embodiment Vertical sectional view of the manufacturing apparatus of the embodiment Vertical sectional view of the manufacturing apparatus of the embodiment

Embodiments of the present invention will be described below with reference to the drawings.
The molded product 10 for packaging according to the embodiment shown in FIG. 1 is used as a packaging container for packaging products such as food.

  This molded product 10 for packaging includes an elliptical bottom surface 11, a side surface 12 that rises and rises from the entire circumference of the bottom surface 11, a flange 13 that projects substantially horizontally from the entire upper edge of the side surface 12, and the entire outer edge of the flange. And an edge winding portion 14 curled from the periphery.

Here, the bottom surface 11, the side surface 12, and the flange 13 of the molded product 10 for packaging constitute a bowl-shaped main body that opens upward, and the edge winding portion 14 is packaged by increasing the thickness of the opening edge of the main body. The overall rigidity of molded products is increased.
The molded article 10 for packaging is formed from unstretched plastics such as unstretched polyethylene terephthalate, unstretched polypropylene, and unstretched polystyrene.

  The molded product 10 for packaging is manufactured from the pre-molded product p for packaging shown in the figure by using a manufacturing apparatus 20 as shown in FIGS.

As shown in FIGS. 2 and 3, the packaging pre-molded product p has a bottom surface 11 that is elliptical in plan view, a side surface 12 that rises from the entire periphery of the bottom surface 11, and a substantially horizontal surface from the entire upper edge of the side surface 12. And an elliptical cylindrical winding allowance 15 provided continuously around the entire outer periphery of the flange 13. The leading end of the winding margin 15 is warped outward.
Here, the bottom surface 11, the side surface 12, and the flange 13 of the pre-molded product p are similar to the bottom surface 11, the side surface 12, and the flange 13 of the packaging molded product 10.

This pre-molded product p is produced by forming a raised portion in a saddle shape by vacuum molding or compressed air molding on a sheet made of unstretched plastic, and cutting the peripheral edge of the portion to separate it from the sheet body. The
The raised portion of the sheet corresponds to the main body of the pre-molded product p and the winding allowance 15, and a sharp cut surface that accompanies the separation appears at the tip portion that warps the outside of the winding allowance 15.

  As shown in FIGS. 2 to 5, the manufacturing apparatus 20 according to the embodiment includes a lower mold 21 and an upper mold 22 that are arranged in parallel in the vertical direction.

  The lower die 21 made of metal such as aluminum, brass, or iron has an inner male die 21b that cannot be raised and lowered with respect to the lower pedestal 21a on an upper surface of the lower pedestal 21a and an outer die that can be raised and lowered with respect to the lower pedestal 21a. And a lower curling mold 21e. Here, as for the lower mold | type 21, the lower base 21a itself is being fixed and cannot raise / lower.

  The male mold 21b, which is substantially elliptical in plan view and convex upward, has a top surface on which the main body of the pre-molded product p, that is, the bottom surface 11, the side surface 12, and the flange 13 can be fitted. Is fitted with the winding allowance 15 of the pre-molded product p.

Further, the male mold 21b has a heat insulating portion 21c inside thereof, and a portion where the main body of the pre-molded product p is fitted and a portion where the winding allowance 15 is fitted are insulated. This heat insulating portion is formed of a known heat insulating material such as a glass cloth or a glass epoxy composite material.
The male mold 21b is fixed to the upper surface of the lower pedestal 21a via the inner support pillar 21d.

The lower curling die 21e having a substantially elliptical ring shape in plan view has a heater 21f at an appropriate location inside so that the whole can be heated. Although the heating temperature is not specifically limited, For example, it is 60-120 degreeC.
The lower curling mold 21e has a curling groove 21g having an elliptical ring shape in plan view and a semicircular cross section on the inner peripheral side of the upper surface thereof. The depth of the curling groove 21g is not particularly limited, but is, for example, 1.5 to 2.0 mm.

Further, the lower curling die 21e is attached to the upper surface of the lower pedestal 21a via the outer cylinder 21h. A seal ring shown in the figure is attached to the outer periphery of the outer cylinder 21h, whereby the outer cylinder 21h is fitted in a hole formed in the upper surface of the lower pedestal 21a. For this reason, when the outer cylinder 21h is moved in a piston motion, the lower curling die 21e moves up and down with respect to the lower pedestal 21a.
With respect to the raising / lowering range of the lower curling mold 21e, the lower limit is when the outer cylinder 21h contacts the bottom of the hole of the lower pedestal 21a, and the illustrated shoulder formed on the lower inner periphery of the lower curling mold 21e is the male mold 21b. The upper limit is when it contacts the lower surface.

  The upper die 22 made of metal such as aluminum, brass, or iron has an inner female die 22b that can be raised and lowered with respect to the upper pedestal 22a, and an outer die 22 that cannot be raised and lowered with respect to the upper pedestal 22a. And an upper curling mold 22d. Here, the upper mold 22 can also be moved up and down by a well-known mechanism.

The female die 22b, which is substantially elliptical in plan view and recessed upward, has a lower surface that fits into the upper surface of the male die 21b with almost no excess (see FIG. 3), and the upper base 22a via the inner cylinder 22c. It is attached to the lower surface of the.
The illustrated seal ring is mounted on the outer periphery of the inner cylinder 22c, whereby the inner cylinder 22c is fitted in a hole formed in the lower surface of the upper base 22a. For this reason, when the inner cylinder 22c is caused to perform a piston motion, the female mold moves up and down with respect to the upper base.
The raising / lowering range of the female die 22b is the upper limit when the inner cylinder 22c contacts the bottom of the upper pedestal 22a, and the illustrated shoulder portion formed on the upper outer periphery of the female die 22b contacts the upper curling die 22d. The descent limit is when touching.

The upper curling die 22d having a substantially elliptical ring shape in plan view has a heater 22e at an appropriate location inside so that the whole can be heated. Although the heating temperature is not specifically limited, For example, it is 60-120 degreeC.
The upper curling die 22d has a curling groove 22f having an elliptical ring shape in plan view and a semicircular cross section on the inner peripheral side of the lower surface thereof. The depth of the curling groove 22f is not particularly limited, but is, for example, 1.4 to 1.9 mm.

When the upper pedestal 22a is lowered, the curling groove 22f overlaps with the curling groove 21g of the lower curling mold 21e almost without deficiency so that a substantially donut-shaped (circular cross-section) space having an open inner peripheral side can be formed. Yes.
The upper curling die 22d is fixed to the lower surface of the upper pedestal 22a via an outer support column 22g.

  The configuration of the packaging molded product manufacturing apparatus 20 is as described above. Next, a method for manufacturing the packaging molded product 10 from the packaging pre-molded product p using the apparatus 20 will be described.

As shown in FIG. 2, first, the packaging pre-molded product p is fitted on the upper surface of the male mold 21 b of the lower mold 21 with the entire upper mold 22 of the manufacturing apparatus 20 raised.
At this time, the heat of the heater 21f of the lower curling mold 21e is not transmitted to the main body of the pre-molded product p for packaging by the heat insulating portion 21c in the male mold 21b, and thermal deformation of the pre-molded product main body is prevented. It is peeling off.

  Here, the lower curling die 21e of the lower die 21 and the female die 22b of the upper die 22 are in the lower limit position with respect to the upper and lower pedestals 21a and 22a, respectively. Further, the female mold 22b is always pressed downward, that is, elastically pushed down by the force of the compressed air, by introducing the compressed air between the inner cylinder 22c and the hole of the upper base 22a.

  Next, as shown in FIG. 3, the entire upper die (upper pedestal 22a) is lowered, and the upper surface of the male die 21b of the lower die 21 is fitted into the lower surface of the female die 22b with almost no excess and the upper curling die 22d. Are brought into contact with the upper surface of the lower curling die 21e.

At this time, as shown in the figure, the female die 22b urged downward is pushed by the male die 21b and moves to the upper limit position with respect to the upper base 22a.
Further, as shown in the drawing, the leading end portion of the winding allowance 15 of the packaging pre-molded product p is introduced into the substantially donut-shaped space formed by matching the upper and lower curling grooves 21g and 22f. It will be. Since the leading end of the winding margin 15 is warped outward, this introduction is performed smoothly. The winding allowance 15 is softened by the heat of the curling dies 21e and 22d.

  From this point, while raising the entire upper mold (upper pedestal 22a) as shown in FIG. 4, the outer cylinder 21h of the lower mold 21 is operated to raise the lower curling mold 21e at substantially the same speed as the upper pedestal 22a. Thereby, the contact state of the upper and lower curling dies 21e and 22d is maintained. Further, since the female die 22b is biased downward, the female die 22b is lowered relative to the upper pedestal 22a and the fitted state of the male die 21b and the female die 22b is maintained.

At this time, the upper and lower curling dies 21e, 22d are raised, and the heights of the overlapping male dies 21b and female dies 22b do not change, so the curling grooves 21g, 22f approach the upper surface of the male dies 21b and the lower surface of the female dies 22b. .
For this reason, as shown in the drawing, the winding margin 15 of the packaging pre-molded product p softened by introducing the tip into the curling grooves 21g, 22f of the upper and lower curling dies 21e, 22d is the upper surface of the overlapping male mold 21b and the female mold 22b. It will be wound up (it will be wound up) toward the opening of the main body of the packaging pre-molded product p fitted to the lower surface.

  In this way, the winding margin 15 is wound up to form the edge winding portion 14 and the packaging molded product 10 is completed. Since the sharp cut surface at the leading end of the winding margin 15 is wrapped inside and hidden, there is no risk of hurting the hand with the cut surface when handling the molded article 10 for packaging.

  Here, the width (height) of the roll allowance 15 of the pre-molded product p is not particularly limited, but if it is too small, curling is difficult to form, and if it is too large, the edge winding becomes large and the aesthetic appearance is impaired. 9 to 13 mm is particularly preferable.

  Finally, as shown in FIG. 5, the entire upper die (upper pedestal 22a) is further raised until the female die 22b and the male die 21b of the lower die 21 are separated from each other, and the finished packaging that fits into the male die 21b. The molded product 10 is removed.

By having the edge winding part 14, the rigidity of the molded product 10 for packaging is improved, so that the thickness of the plastic sheet as the material can be reduced. Therefore, the material cost can be reduced. Although the thickness of a sheet | seat is not specifically limited, For example, they are 0.13 mm-0.45 mm.
Further, the presence of the edge winding portion 14 also improves the fitting force when a lid is fitted into the opening of the molded product 10 for packaging used as a packaging container.

In the said embodiment, although the molded article 10 for packaging was made into the ellipse in planar view, it is not limited to this, It can be set as various shapes, such as circular, a rectangle, a polygon, an oval, and a star shape.
The shape of the main body of the molded product 10 is not limited to the shape having the bottom surface 11, the side surface 12, and the flange 13, and can be a general bowl shape including a dome-shaped curved surface shape.
Moreover, you may provide a rib and embossing in the bottom face 11 and the side surface 12 of the molded article 10 for packaging.

In particular, as described above, the manufacturing apparatus 20 according to the embodiment is suitably used for manufacturing a molded product 10 for packaging that is non-circular in plan view because the manufacturing object is not rotated.
The shapes of the lower mold 21 and the upper mold 22 can be appropriately changed according to the shape of the molded product 10 for packaging. For example, when the bottom surface of the packaging molded product 10 is rectangular, the male mold 21b of the lower mold 21 and the female mold 22b of the upper mold 22 are also rectangular in plan view.
The male mold 21b may be attached with a cooler for cooling the entire male mold 21b in place of the heat insulating portion 21c.

  In addition, although the packaging container was illustrated as the molded article 10 for packaging, it is needless to say that the molded article 10 for packaging may be a lid that closes the opening of the container.

10 Molded products for packaging (packaging containers)
DESCRIPTION OF SYMBOLS 11 Bottom surface 12 Side surface 13 Flange 14 Edge winding part 15 Rolling allowance 20 Manufacturing apparatus 21 of the molded product for packaging 21 Lower mold 21a Lower base 21b Male mold 21c Heat insulation part 21d Inner support pillar 21e Lower curling mold 21f Heater 21g Curling groove 21h Outer cylinder 22 Upper mold 22a Upper base 22b Female mold 22c Inner cylinder 22d Upper curling mold 22e Heater 22f Curling groove 22g Outer support pillar p Pre-molded product for packaging

Claims (1)

A step of molding a pre-molded product for packaging having a cylindrical main body and a cylindrical winding allowance continuously provided on the entire periphery of the opening edge of the vertical main body from an unstretched plastic sheet ;
Preparing a cylindrical curling mold in which an annular curling groove extending in the circumferential direction is formed on the inner peripheral surface;
Setting the pre-molded product so that the saddle mold body is inside the curling mold and the leading end of the winding allowance is introduced into the curling groove of the curling mold;
While the curling mold is heated, the curling groove softened by the heating of the curling mold is slid in the axial direction so that the curling groove approaches the opening edge of the premolded bowl mold body. A method of manufacturing a molded product for packaging, comprising: a step of forming an edge winding portion by winding the wire toward an opening edge.

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