WO2011037242A1

WO2011037242A1 - Container and manufacturing method for same

Info

Publication number: WO2011037242A1
Application number: PCT/JP2010/066738
Authority: WO
Inventors: 功武水越; 能史福山; 一郎松野; 宏智菅原; 卓治朝日
Original assignee: 東洋科学株式会社; 雪印乳業株式会社
Priority date: 2009-09-28
Filing date: 2010-09-28
Publication date: 2011-03-31
Also published as: JP2011068397A; JP5543749B2

Abstract

Presented is a plastic container that can be easily used by consumers even when container thickness is reduced. The plastic container has a main body and a lid section formed to cover the opening in said body. The main body has a base section and a side wall extending along the edge of the base section in a circular shape. The thickness of the base section is 0.47-0.55mm, the thickness of the first and third side walls is 0.38-0.45mm, the thickness of the second and forth side walls is 0.43-0.50mm, and the thickness ratio of the side walls of the second and forth walls to the first and third walls is 1.07-1.20. A roughened area having a surface roughness of 10-30μm is formed on the external surface of the four side walls and the four corners.

Description

Container and manufacturing method thereof

The present invention relates to a resin container for storing food such as butter and margarine and a method for manufacturing the same.

Many foods are sold in plastic containers. For example, Japanese Patent No. 3457230, Utility Model Registration No. 3093848, Japanese Utility Model Laid-Open No. 7-40489, and Japanese Utility Model Laid-Open No. 7-17746 describe examples of food containers such as butter and margarine.

Japanese Patent No. 3457230 Utility model registration No. 3093848 ACT 7-40489 Utility Kaihei 7-17746

In recent years, there has been an increasing demand for reducing the environmental load, and in order to answer this, a reduction in the weight of the resin container, that is, a reduction in weight, is required. For example, in the past, the amount of resin used in one container was 18 grams, but today it is required to be reduced to 14 grams or less. In order to reduce the weight of the resin container, the thickness of the container may be reduced.

However, when the thickness of the container is reduced, the container is easily bent. Therefore, for example, when the consumer grasps the container by hand, the container is easily deformed and becomes slippery. Therefore, there is a risk of accidentally dropping the container. Furthermore, it has also been found that when the molded container is put into a process of filling food such as margarine, the frequency with which the lid is removed due to collision between the containers increases. That is, when containers collide on the conveyor, the containers are bent and the lid is easily removed. In order to prevent this, the fitting force between the container body and the lid may be strengthened. For example, what is necessary is just to enlarge the depth of the unevenness | corrugation of a fitting rib. However, this makes it difficult for the consumer to remove the lid. The consumer accidentally drops the container when removing the lid.

An object of the present invention is to facilitate handling by consumers even if the thickness of the container is reduced.

According to the present invention, the roughened region is formed on the outer surface of the side wall of the main body of the resin container. That is, the surface roughness of the outer surface of the side wall of the container body is increased.

According to the present invention, since the roughened region is formed on the outer surface of the side wall of the main body of the container, even if the consumer grasps the container by hand, it does not slide and fall.
Furthermore, according to the present invention, it has been found that since the roughened region is formed on the outer surface of the side wall of the main body of the container, dirt is difficult to adhere. This will be described.

When the resin container is placed in the refrigerator, condensation occurs on the surface, which may cause dirt to adhere. However, contamination is also caused by static electricity. Usually, the resin contains a surfactant for preventing static electricity. This is to prevent the container from being soiled by static electricity during mold release. The surfactant exudes from the inside of the resin, covers the surface, and forms a surfactant film. When the roughened region is formed on the surface of the resin container, the surface area increases, the surface area of the surfactant coating increases, and the effect of preventing static electricity increases. For this reason, the surface of the resin container is less likely to become dirty.

It is a figure which shows the main body and lid | cover of a container by this invention. It is a figure which shows the structural example of the metal mold | die of the injection molding apparatus which shape | molds the main body of the container by this invention. It is a figure which shows the state which the metal mold | die of FIG. 2 closed. It is a figure which shows the state which the metal mold | die of FIG. 3 opened. It is a figure which shows from the state which the main body of the container released from the metal mold | die. It is a figure which shows the state with which the main body of the container was mounted | worn with the lower mold | type when the metal mold | die of FIG. 3 opened. It is a figure explaining a shape to the inner surface of the side wall of the main body of the container of this invention. It is a figure which expands and shows the corner | angular part of the engagement wall of the main body of the container by this invention. It is a figure explaining the fitting rib formed in the engagement edge of the main body of the container of this invention. It is a figure explaining the level | step difference of the fitting rib formed in the engagement edge of the main body of the container of this invention.

FIG. 1 shows an example of a container according to the present invention. The container of this example has a main body 1 and a lid (lid) part 2. The main body 1 has a bottom 10 and a side wall, and has a substantially rectangular opening 3. The side walls have relatively long first and

third side walls

11, 13, relatively short second and

fourth side walls

12, 14, and four

curved corners

15, 16, 17, 18. The first and

third side walls

11 and 13 are hereinafter referred to as

long side walls

11 and 13, and the second and

fourth side walls

12 and 14 are hereinafter referred to as

short side walls

12 and 14. Called. The

curved corners

15, 16, 17, 18 are hereinafter referred to as

corner sidewalls

15, 16, 17, 18.

A collar 31 is formed on the outer surface of the side wall. The flange 31 is formed in a flange shape along the entire circumference at the upper end of the side wall. A step 32 extending along the entire circumference is formed on the inner surface of the side wall of the container. The step 32 is disposed at the same height as the flange 31 or slightly above the flange. An engaging edge protrudes upward along the entire circumference on the upper side of the flange portion 31. The engagement edges, like the side walls, are relatively long first and

third engagement edges

21, 23, relatively short second and

fourth engagement edges

22, 24, and four curved corners.

Parts

25, 26, 27 and 28. The relatively long first and

third engagement edges

21 and 23 are hereinafter referred to as long-

side engagement edges

21 and 23, and the relatively short second and

fourth engagement edges

22 and 24 are denoted by Hereinafter, the

engagement edges

22 and 24 on the short side are referred to. The

curved corners

25, 26, 27, 28 are hereinafter referred to as

corner engagement edges

25, 26, 27, 28.

Notches

22A and 24A are formed in the short

side engagement edges

22 and 24, respectively. This notch is provided to hold the butter knife. Fitting ribs 25A to 28A are formed on the outer surfaces of the engagement edges 25 to 28 at the four corners, respectively.

The longitudinal dimension of the opening 3 on the upper surface of the main body 1 is 120 to 150 mm, and the longitudinal dimension is 90 to 120 mm. The longitudinal dimension / longitudinal dimension of the opening 3 is 1.2 to 1.4. The height of the main body 1 is 25 to 55 mm.
The container of this example is a thin container. In thin-walled containers, the rate at which defective products are generated increases. In particular, when the thickness of the container having the fitting rib is reduced, defective products are likely to be generated. Therefore, the inventor of the present application has a side wall thickness of 0.38 to 0.45 mm, a side wall thickness of 0.43 to 0.50 mm and a bottom thickness of 0. It has been found that the thickness is 47 to 0.55 mm, the thickness of the side wall on the short side is larger than the thickness of the side wall on the long side, and the ratio is 1.07 to 1.20.

According to this example, the outer surface of the side wall of the container body is roughened. This is referred to as a roughened region. The surface roughness (depth) of the roughened region is 10 to 30 μm. The roughened regions 11A to 18A (only 11A and 12A are shown) extend along the entire circumference of the outer surface of the side wall of the container. The roughened region may be formed entirely from the upper end to the lower end of the side wall, but preferably does not extend to the lower end of the side wall. The width in the height direction of the region below the roughened region may be 0.1 mm to 1 mm. The surface roughness of this region and the bottom 10 of the container is 3 to 6 μm and is surface-treated. As described above, the surface roughness of the bottom 10 of the container and the surrounding area is set to 3 to 6 μm because the container is made slippery when the movement of the container is hindered by a stopper or the like on the production line. This is to prevent troubles from occurring and to prevent dirt from adsorbing to the surface when the bottom 10 and other objects are in contact friction.

The main body of the container of the present invention is made of resin. As the resin used for the main body of the container of the present invention, a thermoplastic resin such as polypropylene, polyethylene, polyvinyl chloride, or ethylene / vinyl / acetate is used.

An injection molding apparatus for molding the container body 1 by injection molding will be described with reference to FIGS. As shown in FIG. 2, the injection molding apparatus includes an upper mold 110, a lower mold 100, and a stripper 121. The inner surface 100A of the lower mold 100 is roughened. Thereby, as described with reference to FIG. 1, a roughened region is formed on the outer surface of the side wall of the main body. Various methods are known as the surface roughening method. For example, a sand blast method, a sand paper method, or the like may be used. As shown in FIG. 3, by engaging the two molds, a cavity 200 having a shape corresponding to the shape of the main body of the container is formed between the two molds. A stripper 121 for mold release is inserted between the two molds. A partition line 125 extending in the vertical direction is formed between the upper mold 110 and the stripper 121, and a partition line 122 extending in the horizontal direction is formed between the lower mold 100 and the stripper 121. In the partition line, the two engaging surfaces are in contact with each other, but in reality, a slight gap is formed between the two engaging surfaces. This gap is provided for air escape and is called an air slit. The air slits are formed at positions corresponding to the upper edges of the engagement edges 21 to 24 and 25 to 28 at the side walls and the corners, the upper edges of the

notches

22A and 24A, and the outer edge of the collar portion 31. Yes. The resin that has entered the air slit is called a burr.

A resin injection port 101 is formed in the lower mold 100. The molten resin introduced from the inlet 101 proceeds from the cavity portion corresponding to the bottom of the container body to the cavity portion corresponding to the side wall of the container body, as indicated by the arrow, The cavity part corresponding to the part is filled, and further the cavity part corresponding to the engagement edge of the container body is advanced. As the resin advances in the cavity, the air in the cavity is expelled and discharged to the outside through the air slit. When the resin reaches the cavity portion corresponding to the upper edge of the engagement edge of the main body of the container and the outer edge of the flange of the main body, the filling of the resin is completed.

This will be described with reference to FIG. When taking out the main body 1 of the resin container, first, the upper mold 110 is moved upward. The molded container body 1 moves upward together with the upper mold 110 while being engaged with the upper mold 110. Therefore, when the stripper 121 is moved downward, the container body 1 is released from the upper mold 110 as shown in FIG.

However, according to this example, as shown in FIG. 6, when the upper mold 110 is moved upward, the container body 1 is engaged with the lower mold 100 instead of the upper mold 110. Turned out to be retained. This is because the friction coefficient between the inner surface 100A of the lower mold 100 and the main body is increased because the inner surface 100A of the lower mold 100 is roughened. Therefore, the main body 1 of the container is held away from the upper mold 110 and engaged with the lower mold 100. The stripper 121 is provided on the assumption that the main body 1 of the container is held in an engaged state with the upper mold 110. Therefore, additional work is required to remove the main body 1 of the container engaged with the lower mold 100.
Therefore, the inventors of the present application have considered a configuration for holding the main body 1 of the container in an engaged state with the upper mold 110 when the upper mold 110 is moved upward. That is, the friction coefficient between the upper mold 110 and the inner surface of the container main body 1 may be increased.

Referring to FIG. 7, the idea that the inventors of the present application have considered will be described. In the first plan, first, a convex portion 111 or a rib is provided on the inner surface of the side wall 11 of the main body 1 of the container. In order to form the convex portion 111 on the inner surface of the side wall 11 of the container body 1, a corresponding concave portion may be formed in the upper mold 110. The main body 1 of the container is held by the upper mold 110 by engaging the convex portions 111 on the inner surface of the side wall 11 of the main body 1 of the container with the corresponding concave portions of the upper mold 110. Therefore, when the upper mold 110 is moved upward, the main body 1 of the container is held in a state of being engaged with the upper mold 110. However, inconvenience arises when the convex portions 111 or ribs are provided on the inner surface of the side wall 11 of the main body 1 of the container. This hinders the placement of a cover over the margarine. Therefore, the inventor of the present application has considered providing a convex portion 112 or a rib on the upper end of the side wall 11 of the main body 1 of the container, avoiding the position where the lid member is disposed. However, when the consumer uses the butter knife, the protrusion 112 is obstructed. Therefore, the 1st proposal which provides the

convex part

111 or 112 in the inner surface or upper end of the side wall 11 of the main body 1 of a container is not optimal.

Therefore, the inventor of the present application considered the second plan. In the second plan, a recess 211 or a groove is provided on the inner surface of the engaging edge 21 extending on the side wall 11 of the main body 1 of the container. The thickness of the engagement edge 21 is slightly larger than the thickness of the side wall 11 but larger. Therefore, the recess 211 is formed on the inner surface of the engagement edge 21. The inventor of the present application conducted an experiment of molding a resin main body by changing the depth D1 and the dimension L of the recess 211. According to this, the depth D1 of the recess 211 provided on the inner surface of the engagement edge 21 of the container body 1 is 0.05 to 0.08 mm, and the longitudinal dimension L of the recess 211 is 1.0 to 1.4 mm. When good results were obtained. In this example, the distance H1 from the flange 31 to the upper edge of the engagement edge 21 is H1 = 3 to 10 mm.

Thus, by providing the recess 211 not on the side wall 11 of the main body 1 of the container but on the engaging edge 21, the depth D1 of the recess 211 can be made relatively small. The reason will be explained. When the upper mold 110 is moved upward and the lower mold 100 is released, the side wall 11 of the container body 1 is released by the pressing force from the lower mold 100. Therefore, the side wall 11 of the main body 1 of the container is slightly deformed and expands outward. Thereby, the engagement force between the upper mold 110 and the side wall 11 of the main body 1 of the container is weakened. However, the engagement edge 21 of the container body 1 is sandwiched between the upper mold 110 and the stripper 121. Therefore, the engagement edge 21 of the main body 1 of the container does not spread outward. Therefore, when the recess is provided on the inner surface of the side wall 11 of the main body 1 of the container, the depth has to be relatively large, but when the recess 211 is provided on the engagement edge 21 of the main body 1 of the container, The depth D1 may be relatively small.

If the depth D1 of the recess 211 is too small, the main body 1 of the container could not be held in an engaged state with the upper mold 110 when the upper mold 110 was moved upward. This is because the engagement force between the upper mold 110 and the recess 211 of the container body 1 is small. On the other hand, it was found that when the depth D1 of the recess 211 is too large, the shape of the recess 211 is deformed, and the resin on the upper side of the recess 211 is plastically deformed. The plastic deformation of the resin on the upper side of the recess 211 extends to the upper edge of the engagement edge 21 and a protrusion may be formed at the upper edge of the engagement edge 21.

A description will be given of the roughened region 11A formed on the outer surface of the side wall of the main body of the container. As shown, the roughened region 11A may be formed entirely from the upper end to the lower end of the side wall 11, but is preferably not formed at the lower end of the side wall. The width H2 in the height direction of the region below the roughened region 11A may be 0.1 mm to 1 mm. The inclination angle θ at the boundary between the side wall and the bottom of the main body of the container is 4 to 10 °.

FIG. 8 schematically shows an enlarged engagement edge 25 at the corner of the container body. The fitting rib 25A is a protrusion extending along the circumferential direction on the outer surface of the engaging edge 25 at the corner. The fitting rib 25 A extends in a circumferential shape between the edge of the opening 3 and the flange portion 31 at approximately the center in the width direction of the engaging edge 25. On the other hand, a fitting rib (not shown) is also formed on the inner surface of the lid 2. That is, the fitting rib for engaging with the fitting rib of the main body extends along the circumferential direction on the inner surface of the corner portion of the lid portion 2. When the lid 2 is mounted on the main body 1, the peripheral edge of the lid 2 is engaged with the engagement edge of the main body. Thereby, the lid 2 is engaged with the main body 1. At this time, the fitting rib formed on the inner surface of the corner portion of the lid portion 2 is engaged with the fitting rib 25 A of the engagement edge of the corner portion of the main body 1. The main body 1 and the lid 2 of the container are separately molded by an injection molding method.

9 and 10, the engagement of the fitting rib 2A formed on the inner surface of the lid 2 and the fitting rib 25A formed on the outer surface of the engaging edge 25 of the main body 1 will be described. Normally, when the main body 1 is completely closed by the lid 2, the fitting rib 2A of the lid 2 is on the fitting rib 25A of the engagement edge 25 of the main body 1 as shown in FIG. 9A. It is in. That is, the fitting rib 2A of the lid 2 and the fitting rib 25A of the main body 1 are in contact with each other. As described above, when the containers collide on the conveyor, the lid may come off from the main body. However, as shown in FIG. 9B, when the main body 1 is completely closed by the lid 2, the height of the fitting rib 25A of the main body 1, the height of the fitting rib 2A of the lid 2, and the fitting of the lid 2 The distance between the tip of the rib 2A and the outer surface of the engaging edge 25 of the main body 1 and the distance between the fitting rib 2A of the lid 2 and the fitting rib 25A of the main body 1 at the closest part are: When in the predetermined size range, even if containers collide on the conveyor, the lid does not come off from the main body.

Specifically, as shown in FIG. 9A, when the fitting rib 2A of the lid 2 is on the fitting rib 25A of the engaging edge 25 of the main body 1, containers are placed on the conveyor. 90% of all containers were uncovered from the main body. However, when the height or the like of the fitting rib 25A of the main body 1 is within a predetermined size range, even if the containers collide on the conveyor, the lids of all the containers do not come off from the main body. In this way, the lid is no longer detached from the main body because the height of the fitting rib 25A of the main body 1 is within a predetermined size range, even if containers collide on the conveyor. This is considered to absorb the impact. The predetermined dimension range such as the height of the fitting rib 25A of the main body 1 will be described in detail later.

Details of the fitting rib 25A formed on the outer surface of the engaging edge 25 of the main body 1 will be described. As shown in FIG. 10, the fitting rib 25A has a semicircular cross-sectional shape, and a step 25B is formed at the tip thereof. When the consumer fits the lid 2 on the main body 1, the fitting rib 2 A of the lid 2 contacts the fitting rib 25 A of the main body 1, and the fitting rib 2 A of the lid 2 moves on the fitting rib 25 A of the main body 1. When getting over, the main body 1 and the lid 2 are elastically deformed. When the fitting rib 2A of the lid 2 gets over the step 25B of the fitting rib 25A of the main body 1, a snapping sound is generated. The consumer can confirm by the sound that the fitting rib 2A of the lid 2 has climbed over the fitting rib 25A of the main body 1 and the lid 2 is completely engaged with the main body 1.

The dimensions of the fitting rib 25A of the main body 1 and the fitting rib 2A of the lid 2 will be described. As shown in FIG. 9B, the height G1 of the fitting rib 25A of the main body 1 is 0.50 to 0.65 mm, and may be 0.63 mm, for example. The height G2 of the fitting rib 2A of the lid 2 is 0.35 to 0.50 mm, and may be 0.40 mm, for example. A gap G3 between the front end of the fitting rib 2A of the lid 2 and the outer surface of the engagement edge 25 of the main body 1 is 0.30 mm or less. Among the gaps between the fitting rib 2A of the lid 2 and the fitting rib 25A of the main body 1, the gap G4 at the closest part is 0.1 to 0.2 mm, for example, 0.11 mm.

As shown in FIG. 10, in this example, the cross section of the fitting rib 25A of the main body 1 and the fitting rib 2A of the lid 2 is semicircular, but other shapes may be used. A step 25 B is formed in the fitting rib 25 A of the main body 1. The cross section of the step 25B is formed by two concentric circles having different radii. The height of the step 25B corresponds to the difference in radius between the two concentric circles and is 0.1 to 0.3 mm. For example, the radius of curvature of the quarter circle that is the upper cross section of the fitting rib 25A is R = 0.75 mm, and the radius of curvature of the quarter circle that is the lower cross section of the fitting rib 25A is R = 0. .60 mm. As shown in FIG. 9B, the radius of curvature of the semicircle that is the cross section of the fitting rib 2A of the lid 2 may be R = 0.60 mm. The surface of the step 25B is inclined with respect to the radial direction. This inclination angle is 30 to 50 °, and may be 45 °, for example.

The example of the present invention has been described above, but the present invention is not limited to the above-described example, and various modifications can be easily made by those skilled in the art within the scope of the invention described in the claims. It will be understood.

DESCRIPTION OF SYMBOLS 1 ... Main body, 2 ... Cover part, 3 ... Opening, 10 ... Bottom part, 11, 12, 13, 14, 15, 16, 17, 18 ... Side wall, 11A ... Roughening area | region, 21, 22, 23, 24 ... Engagement edge, 22A, 24A ... notch, 25, 26, 27, 28 ... engagement edge, 25A-28A ... fitting rib, 31 ... collar, 32 ... step

Claims

In a container having a main body and a lid configured to cover the opening of the main body,
The main body has a bottom portion and a side wall extending circumferentially along an edge of the bottom portion, and a protrusion-like collar portion extending circumferentially is formed on an upper edge of the outer peripheral surface of the side wall. Is formed with an engagement edge extending circumferentially, an opening of the main body is formed by the edge of the engagement edge, and the lid is engaged with the engagement edge,
The sidewalls have relatively long first and third sidewalls, relatively short second and fourth sidewalls, and four curved corners;
The engagement edge has a relatively long first and third engagement edge, a relatively short second and fourth engagement edge, and four curved engagement edges corresponding to the side wall. ,
The bottom has a thickness of 0.47 to 0.55 mm, the first and third sidewalls have a thickness of 0.38 to 0.45 mm, and the second and fourth sidewalls have a thickness of 0.43 to 0.50 mm, and the ratio of the thickness of the second and fourth sidewalls to the thickness of the first and third sidewalls is 1.07-1.20,
A roughened region is formed on the outer surfaces of the four side walls and the four corners, the surface roughness of the roughened region is 10 to 30 μm, and the surface roughness of the other regions is 3 to 3 μm. A container characterized by being 6 μm.
The container according to claim 1, wherein a non-roughened region that is not roughened is formed at a lower end of the side wall, and a width in a height direction of the non-roughened region is 0.1 mm to 1 mm. A container characterized by.
The container of claim 1,
The longitudinal dimension of the opening of the body is 120 to 150 mm, the longitudinal dimension is 90 to 120 mm, the longitudinal dimension / longitudinal dimension of the opening of the container body is 1.2 to 1.4, The container has a height of 25 to 55 mm.
The container according to claim 1, wherein the main body of the container is formed of 8 to 14 grams of resin.
The container of claim 1,
A cutout is formed in each of the second and fourth engagement edges, and a fitting rib extending along the edge of the opening is formed in each of the four curved engagement edges. A container characterized by.
The container of claim 1,
A concave portion is formed on the inner surface of the engagement edge of the main body, the depth of the concave portion is 0.05 to 0.08 mm, and the longitudinal dimension of the concave portion is 1.0 to 1.4 mm. container.
The container of claim 1,
A protruding rib is formed on the outer surface of the engagement edge of the main body, and a protruding rib is formed on the inner surface of the lid corresponding to the rib of the main body, and the lid is engaged with the main body. When the rib of the inner surface of the lid proceeds over the rib of the main body, and the opening of the main body is completely closed by the lid, the rib of the lid is deeper than the rib of the engagement edge of the main body A container characterized by being separated along a direction.
8. The container according to claim 7, wherein a step is formed on a surface of the rib of the main body.
Engaging a first mold having a convex part with a second mold having a concave part to form a cavity between the two molds;
Injecting molten resin into the cavity;
Separating the two molds when the resin is solidified;
Releasing the resin container engaged with the first mold;
In the manufacturing method of the container containing
The inner surface of the concave portion of the second mold is roughened, and a roughened region is formed on the outer surface of the container corresponding to the roughened region. A method for producing a container, wherein the surface roughness is 10 to 30 μm, and the surface roughness of the other region is 3 to 6 μm.