JP2008137680A - Synthetic resin cup-shaped container - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a synthetic resin cup-shaped container which has never made heretofore light without spoiling the outer appearance, decorativeness, grasping characteristic and forming characteristic of a usual cup-shaped container. <P>SOLUTION: This injection molded synthetic resin cup-shaped container is protrusively formed with many protrusive ribs in parallel longitudinally on the internal peripheral face of a side wall. The thickness of the side wall including the height of the protrusive ribs at the area formed with the ribs is 0.8 mm or less and the gap between the neighboring ribs is between 3 to 10 mm. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a cup-shaped container made of a synthetic resin that has been reduced in weight by being thinned.

Synthetic resin cup-shaped containers are used in large quantities for food applications, etc., but in many cases they are disposable, so they are thinner than ever in terms of resource saving and cost reduction related to packaging. There is a demand for lighter containers.
Of course, if the body wall is thinned, it will be deformed when it is gripped by hand, and if the opening is covered with a cover material in a sealed state, it will be deformed by depression when the inside is in a decompressed state, Furthermore, due to problems such as moldability, there is a limit to the thinning of the wall, and the thickness of the side wall of the cup-shaped container by injection molding, which is considered to be thinned in the past, is about 0.6 to 0.8 mm. Even if the resin used and the injection molding method are specially devised, the limit is about 0.3 to 0.5 mm.

As a method for solving such a problem due to thinning, for example, Patent Document 1 describes a cup-shaped container in which a reinforcing ring member is fitted to the outer peripheral surface of a side wall to suppress this deformation. Moreover, although Cited Document 2 describes a cup-shaped container in which a number of vertical ribs are formed on the outer peripheral surface of the side wall for heat insulation, deformation of the trunk can also be suppressed by such ribs.
Japanese Utility Model Publication No. 5-84737 JP-A-6-32379

However, in a container in which a large number of longitudinal ribs are formed on the outer peripheral surface of the side wall described in Patent Document 2, a heat insulating function is exhibited, but on the other hand, a protrusion formed on the outer peripheral surface. Due to irregularities due to the ribs, the appearance is limited to those with irregularities, and direct decoration such as printing is difficult, so it is necessary to wrap the label so that it is layered on the ribs However, the cost may increase.
Further, there is a problem that the weight of the entire container cannot always be reduced by the amount of resin for forming the ribs.

  The present invention solves the problems associated with the thinning of the synthetic resin cup-shaped container described above, and its technical problems are the appearance, decoration, gripping, and moldability of ordinary cup-shaped containers. The goal is to achieve an unprecedented weight reduction.

Among the means for solving the problems of the present invention, the means of the invention described in claim 1 is:
In a synthetic resin cup-shaped container by injection molding,
On the inner peripheral surface of the side wall, a large number of protruding ribs are projected in parallel in the vertical direction;
The thickness of the side wall including the protruding height of the protruding rib in the portion where the protruding rib is formed is 0.8 mm or less,
The interval between adjacent ribs is in the range of 3 to 10 mm,
It is in.

In order to achieve unprecedented weight reduction by thinning the cup-shaped container by injection molding, it is necessary to reduce the thickness of the side wall to about 0.3 mm or less,
The inventors of the present application suppress the decrease in the rigidity of the container due to this thinning, and also suppress the decrease in the fluidity of the resin in the mold without using a specially devised resin or injection molding method. As a result, the above configuration was found.

When the cup-shaped container is injection-molded, the molten resin injected into the mold cavity from the gate provided at the center of the bottom surface of the molding die is radiated inside the cavity, opening the upper end of the container. Since it flows toward the part corresponding to the part,
According to the above-described configuration of claim 1, a decrease in fluidity in a side wall portion formed to be extremely thin by forming a configuration in which a large number of ribs are formed in parallel in the longitudinal direction on the inner peripheral surface of the side wall. Can be supplemented by the fluidity of the ribs formed in parallel in the flow direction of the molten resin, and the injection moldability is greatly impaired even when the thickness of the side wall is about 0.3 mm. There is no.

  Further, in the portion where the rib ribs are attached, the thickness of the side wall including the height of the rib ribs is 0.8 mm or less, and further, the interval between adjacent rib ribs is 3 mm or more, It is possible to suppress an increase in the amount of resin due to the provision of the ridge ribs and not to impair the effect of thinning the side wall, thereby effectively reducing the amount of resin used for the entire container.

  On the other hand, if the number of formed ribs is reduced, the complementary effect on the rigidity of the container and the fluidity of the resin described above is impaired, so the interval between adjacent ribs should be 10 mm or less. Good.

  According to a second aspect of the present invention, in the first aspect of the invention, the thickness of the side wall including the protruding height of the rib rib is 0.5 mm or more in the portion where the rib rib is attached. ,It is in.

  By the said structure of Claim 2, the rib effect and the complementary effect which concerns on fluidity | liquidity can fully be exhibited by making the thickness of the side wall including the protrusion height of a rib rib into 0.5 mm or more. .

  According to a third aspect of the present invention, in the first or second aspect of the present invention, the protruding height of the rib is set to a value equal to or greater than the thickness of the side wall.

  According to the above configuration of the third aspect, the rib effect can be sufficiently exerted by setting the protruding height of the protruding rib to a value equal to or greater than the thickness of the side wall.

  The invention according to claim 4 is the invention according to claim 1, 2 or 3, wherein the flat cross-sectional shape of the rib rib is rectangular, and the lateral width is in the range of 1 to 3 times the protruding height. It is in.

  According to the above-described configuration of the present invention, the fluidity of the resin can be sufficiently improved by making the flat cross-sectional shape of the ribs rectangular and making the lateral width at least one times the protruding height. By making the value 3 times or less, an increase in the amount of resin due to the ribs can be suppressed.

  According to a fifth aspect of the present invention, in the first, second, third, or fourth aspect of the invention, a plurality of ribs in the longitudinal direction are formed on the inner peripheral surface of the side wall in a gentle spiral shape in parallel. It is in attaching.

  According to the above-described configuration of the fifth aspect, since the rib rib has a spiral shape, the reinforcing effect of the rib rib also acts in the lateral direction, so that the rigidity of the cup-shaped container can be increased more effectively. Can provide a firmer container. Moreover, by using this gentle spiral, the complementary effect relating to the fluidity of the ribs in the injection molding is not impaired.

Since the present invention has the above-described method and configuration, the following effects can be obtained.
In the first aspect of the present invention, the decrease in fluidity in the side wall portion formed to be extremely thin is compensated by the fluidity in the rib rib portion provided in parallel in the flow direction of the molten resin. can do.

  Further, the thickness of the side wall including the height of the ridge rib is set to 0.8 mm or less, and further, the interval between the adjacent ridge ribs is set to a range of 3 mm or more. The increase can be suppressed, and an effective weight reduction of the resin used as the whole container can be achieved without impairing the thinning effect of the side wall. Moreover, the rigidity and moldability of a container can fully be exhibited by making the space | interval between adjacent protrusion ribs into the range of 10 mm or less.

In the invention of claim 2, by making the thickness of the side wall including the protruding height of the rib ribs 0.5 mm or more, the rib effect and the complementary effect related to the fluidity can be sufficiently exhibited. it can.

In the invention according to claim 3, the rib effect can be sufficiently exhibited by setting the protruding height of the protruding rib to a value equal to or greater than the thickness of the side wall.

In the invention of claim 4, the fluidity of the resin can be made sufficiently good by making the flat cross-sectional shape of the ridge rib into a rectangular shape and making the lateral width more than 1 times the protruding height, Moreover, the increase in the amount of resin by a protrusion rib can be suppressed by making a horizontal width into 3 times or less.

In the invention according to claim 5, by making the ribs spiral, the reinforcing effect of the ribs also acts in the lateral direction, so that the rigidity of the cup-shaped container is increased more effectively. Can provide a firmer container. Moreover, by using this gentle spiral, the complementary effect relating to the fluidity of the ribs in the injection molding is not impaired.

Embodiments of the present invention will be described below with reference to the drawings.
1 to 4 show a first embodiment of a cup-shaped container according to the present invention. FIG. 1 is a half longitudinal front view, FIG. 2 is a plan view, FIG. 3 is a bottom view, and FIG. FIG. 4B is a cross-sectional plan view in the vicinity of the protruding rib, showing an enlarged main portion along the line AA in FIG. 4A.
This cup-shaped container 1 is an injection-molded product made of polypropylene resin, has a bottom portion 3, a side wall 2 has a cylindrical shape whose diameter is slightly increased upward, and a flange 4 is provided around an upper end opening edge. .

On the inner peripheral surface of the side wall 2, a large number of protruding ribs 5 are formed in parallel in the vertical direction (40 in this embodiment).
Further, at the height position near the lower end of the inner peripheral surface of the side wall 2, projecting pieces 7 for preventing stacking are attached at six equicentered angles.

The dimensions of the cup-shaped container 1 are as follows.
The height of the cup-shaped container 1 is 109 mm, the outer diameter of the upper end portion of the side wall 2 is 62 mm, the outer diameter of the lower end portion is 49 mm, and the average value of the thickness t2 of the side wall 2 is 0.25 mm.
Further, the planar cross-sectional shape of the protruding rib 5 is rectangular, the protruding height H is 0.35 mm, the lateral width W is 0.7 mm, and the interval S between adjacent protruding ribs 5 is 6 mm at the upper end and the lower end. It is 4 mm in part. (See FIG. 2, FIG. 4 (a), (b))

  Therefore, the thickness t1 of the side wall 2 including the protrusion height H of the rib rib 5 in the portion where the rib rib 5 is formed is 0.6 mm, and is in the range of 0.5 to 0.8 mm. . The protrusion height H of the rib rib 5 is 1.4 times the wall thickness t2 of the side wall 2, and the lateral width W of the rib rib 5 is twice the protrusion height H, which is in the range of 1 to 3 times. It is within.

  Then, as described above, the average value of the wall thickness t2 of the side wall 2 is set to 0.25 mm, which is an unprecedented thin wall, and the dimensions (projection height H, lateral width W, interval S) related to the ridge rib 5 are as described above. By setting as described above, in the cup-shaped container 1 of this embodiment, due to the complementarity related to the fluidity of the resin by the protruding rib 5 portion (without using a specially devised resin or injection molding method), it is possible to perform injection molding. The weight can be reduced to 11.6 g without impairing such high productivity, and the conventional lightweight cup-shaped container having the same shape (with an average wall thickness of about 0.6 to 0.8 mm and a weight of Compared to about 15 g), a significant weight reduction could be achieved.

Further, the protruding rib 5 formed on the inner peripheral surface of the side wall 2 has an extremely low protrusion height H of 0.35 mm as compared with a rib formed on the outer peripheral surface of a conventional heat insulating container or the like. However, the reinforcing effect is sufficiently exerted, the large deformation can be suppressed even when the side wall 2 is grasped by hand, regardless of the thinning of the side wall 2 which is not conventional, and good gripping properties are exhibited. I was able to.
Moreover, since the outer peripheral surface of the side wall 2 has no unevenness and is flat like a conventional cup-shaped container, it can be directly decorated by printing or the like.

Next, FIG. 5 is a half longitudinal front view of the second embodiment of the cup-shaped container of the present invention.
In this embodiment, on the inner peripheral surface of the side wall 2, a large number of protruding ribs 5 are gently spiraled and formed in parallel, and the reinforcing effect of the protruding ribs 5 is lateral. Therefore, the rigidity of the cup-shaped container 1 can be increased more effectively, the side wall 2 can be prevented from being crushed more effectively by gripping, and a firmer container can be provided. .

Further, by using this gentle spiral, the injection effect can be easily performed without impairing the complementary effect related to the fluidity of the rib 5 in the injection molding.
Even if the rib 5 is formed in a spiral shape in this way, in the injection molding, the molded product and the core mold can be easily removed while being relatively rotated.

  As mentioned above, although embodiment of this invention was described along the Example, the aspect of this invention is not limited to these Examples. For example, the cup-shaped container may have an elliptical cylinder shape or a square cylindrical shape in addition to the cylindrical shape, and the resin used is not limited to polypropylene resin.

  Moreover, although the example which forms a rib rib over the substantially whole height range of a side wall was shown in the Example mentioned above, it does not necessarily need to make a formation range into the substantially whole height range of a side wall in this way, for example, mainly For example, the ribs are formed in the upper half of the height range to be the gripping part, and the side walls are slightly thicker than the upper half in the lower half of the height range without the ribs. The height range formed by the protruding ribs can be determined in consideration of the effect of forming. Moreover, the height range in which individual ribs of a large number of ribs in parallel are formed can be continuously changed so that it can be easily gripped as a whole.

  As described above, the cup-shaped container of the present invention achieves unprecedented weight reduction within a range that does not impair gripping properties and injection moldability, and can reduce the material cost. Wide range of application development is expected.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a half longitudinal front view of a first embodiment of a cup-shaped container of the present invention. It is a top view of the cup-shaped container of FIG. It is a bottom view of the cup-shaped container of FIG. (A) In the cup-shaped container of FIG. 1, the longitudinal cross-sectional view shown along a rib rib, and the rib rib which expands and shows a principal part along the AA line in (b) (a). It is a plane sectional view of the neighborhood. It is a half vertical front view of 2nd Example of the cup-shaped container of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1; Cup-shaped container 2; Side wall 3; Bottom part 4; Flange 5; Projection rib 7; Projection piece H; Projection height W; Horizontal width t1, t2;

Claims (5)

It is due to injection molding, and on the inner peripheral surface of the side wall (2), a number of protruding ribs (5) are formed in parallel in the vertical direction, and in the part where the protruding ribs (5) are formed, The wall thickness (t1) including the protruding height (H) of the rib rib (5) is 0.8 mm or less, and the interval (S) between the adjacent rib ribs (5) is 3 to 10 mm. A synthetic resin cup-shaped container characterized in that The synthetic resin according to claim 1, wherein the thickness (t1) of the side wall including the protruding height (H) of the protruding rib (5) in the portion where the protruding rib (5) is formed is 0.5 mm or more. Cup-shaped container. The synthetic resin cup-shaped container according to claim 1 or 2, wherein the protruding height (H) of the protruding rib (5) is a value equal to or greater than the thickness (t2) of the side wall. The cup made of synthetic resin according to claim 1, 2, or 3, wherein the flat cross-sectional shape of the ribs (5) is rectangular and the width (W) is in the range of 1 to 3 times the protruding height (H). Container. The synthetic resin cup-shaped container according to claim 1, 2, 3, or 4, wherein the ribs (5) have a gentle spiral shape.

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