JP2009262977A - Resin cap - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resin cap which can be easily removed from a bottle and the whole of which can be easily removed from an opening part of a container to open. <P>SOLUTION: This resin cap includes a top plate 1 and a skirt wall 2, wherein the outer surface of the skirt wall 2 is formed with a flange-like seal opening tab 10 protruded outward, the inner surface of the top plate 1 is formed with an inner ring 3 spaced apart from the skirt wall 2 and extending downward and an opening 50 of a container is fitted in a space between the inner ring 3 and the skirt wall and fixed there. The height ranging from the inner surface of the top plate 1 to the maximum outer diameter part of the outer surface of the inner ring 3 is set in such a way that a height at a seal opening fulcrum point B spaced apart by 180° from a part A corresponding to the central part of a seal opening tab 10 is formed relatively low as compared with the height at the part A corresponding to the central part of the seal opening tab. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a resin cap that is applied to a container having a relatively wide-mouthed spout, such as a milk bottle, and in particular, includes a bowl-shaped opening tab that is fitted into the spout and formed on the outer surface of a skirt wall. The present invention relates to a resin cap of a type that is removed from a container mouth by lifting and opened.

  As a resin cap applied to a container having a relatively wide mouth spout such as a milk bottle, it is composed of a top plate part and a skirt wall hanging downward from the periphery of the top plate part. There is an inner ring that extends downward at an interval, and a container mouth portion is fitted into a space between the inner ring and the skirt wall and is fixed to the container mouth portion. This type of resin cap has a smaller cap height (equivalent to the height of the skirt wall) compared to normal screw caps, etc., so that the cap fitted in the container mouth can be securely locked. A circumferential locking undercut is provided at the lower end of the inner surface. That is, the resin cap is firmly fixed to the container mouth by engaging the undercut with the jaw formed at the container mouth. The outer surface of the skirt wall of the resin cap is provided with a bowl-like opening tab. By lifting the opening tab, the cap fixed to the container mouth is removed, that is, the opening is performed. It has become.

Various types of resin caps as described above have been proposed. For example, Patent Document 1 proposes a resin cap in which scores are provided at portions located at both ends of a skirt wall opening tab. With such a resin cap, opening by lifting the opening tab can be easily performed.
Japanese Utility Model Publication No. 47-13109

  By the way, the known resin cap is devised so that the opening tab can be easily lifted, but there is a problem that so-called separation is bad. That is, in the above-described resin cap, the container mouth portion is firmly fitted between the cap skirt wall and the inner ring, and the container mouth portion is firmly held by the undercut formed on the inner surface of the lower end of the skirt wall. Thus, the cap is effectively prevented from falling off from the container mouth, and good sealing performance is ensured. Therefore, when opening the resin cap, when the opening tab is lifted upward, the cap is lifted sequentially upward from the opening tab side with the portion opposite to the opening tab as a fulcrum. Although the container mouth is tightly fitted between the skirt wall and the inner ring on the opposite side of the opening tab (the fulcrum side when opening), this part is removed from the container mouth. There is a problem that it is difficult to escape, that is, a problem that the separation is bad. If the cap is not separated well, a large force is required at the final stage of removing the fulcrum side located on the opposite side of the opening tab from the container mouth, so when the entire cap is completely removed from the container mouth, This large force may cause inconveniences such as the cap popping and flying.

  In addition, as a material for the resin cap as described above, low-density polyethylene with high flexibility is widely used in order to ensure good sealing performance, but recently, caps have been used to reduce material costs. The height (the height of the skirt wall) is low, and a thin one is desired. However, if such a requirement is satisfied with low-density polyethylene, problems such as poor sealing due to deformation of the cap or dropping off of the cap from the container mouth will be caused. Also, if high-density polyethylene or the like with high rigidity is used, the fitting force between the container mouth and the cap becomes considerably high due to the high rigidity, and the cap is difficult to deform. Become prominent.

  Accordingly, it is an object of the present invention to provide a resin cap that can be easily removed and can be easily removed from the container mouth and opened.

According to the present invention, it comprises a top plate portion and a skirt wall hanging downward from the periphery of the top plate portion, and an outer surface of the skirt wall is formed with a hook-like opening tab protruding outward, An inner ring extending downward with a gap from the skirt wall is formed on the inner surface of the top plate portion, and a container mouth portion is fitted into a space between the inner ring and the skirt wall so as to form a container mouth portion. In the fixed resin cap,
On the outer surface of the inner ring, a portion bulging outward is formed,
The height from the inner surface of the top plate portion to the maximum outer diameter portion of the outer surface of the inner ring is the height at the opening fulcrum portion that is 180 degrees away from the portion corresponding to the center portion of the opening tab when viewed from the top surface to the bottom surface. There is provided a resin cap characterized in that it is formed to be relatively lower than the height of the portion corresponding to the central portion of the opening tab.

In the resin cap of the present invention,
(1) The height from the inner surface of the top plate portion to the maximum outer diameter portion of the outer surface of the inner ring is gradually increased from the opening fulcrum portion toward the portion corresponding to the center portion of the opening tab,
(2) A pair of first scores are symmetrically formed on the skirt wall with the opening fulcrum portion as a center, and a straight line connecting the first score and the cap center, the opening fulcrum portion and the cap center, The angle θ ₁ formed by the straight line connecting the two is 15 to 45 degrees, in particular 25 to 35 degrees,
(3) A pair of second scores are symmetrically formed on the skirt wall with the opening fulcrum portion as the center, and a straight line connecting the second score and the cap center, the opening fulcrum portion and the cap center, The angle θ ₂ formed by the straight line connecting the _two is in the range of 70 to 90 degrees, particularly 80 to 90 degrees,
(4) The resin cap is made of high density polyethylene having a density of 0.950 g / cm ³ or more,
Is preferred.
The inner surface of the top plate portion means the inner surface of the top plate portion on the inner surface side of the inner ring.

  In the resin cap of the present invention, the height d (hereinafter referred to as seal portion height d) from the inner surface of the inner surface of the inner ring to the maximum outer diameter portion of the outer surface of the inner ring corresponds to the center portion of the opening tab. In the opening fulcrum part located on the opposite side to the part, it is formed relatively lower than the part on the opening tab side. Therefore, when the cap is opened by lifting the opening tab upward, the cap is released from the container mouth by lifting the opening tab, and at the same time, the opening fulcrum on the opposite side of the cap is opened. On the side, the inner ring is still held in the container mouth, but the inner ring having a low seal height d is easily bent upward, and the tightening of the container mouth by the inner ring is eased. As a result, the opening fulcrum The cap can be easily detached from the container mouth portion also on the side portion, and the separation property is improved.

  In the present invention, when the pair of first scores are symmetrically formed around the opening fulcrum portion on the skirt wall, the skirt wall on the side of the opening fulcrum portion is opened when the cap is opened by lifting the opening tab. When the stress is concentrated on the skirt wall and the pair of second scores are symmetrically formed on the skirt wall, the cap can be easily removed from the container opening on the side of the opening fulcrum of the cap. Removal from the container side on the part side can be performed more easily, and the separation property can be further improved.

  The present invention can ensure excellent separation performance even when applied to a cap made of high-density polyethylene having a low height and suitable for a thin-walled cap in order to reduce material costs. .

Hereinafter, the present invention will be described in detail based on specific examples shown in the accompanying drawings.
FIG. 1 is a side sectional view showing an example of the resin cap of the present invention.
FIG. 2 is a bottom view of the cap of FIG.
FIG. 3 is a side sectional view showing the cap of FIG. 1 together with the container mouth portion,
FIG. 4 is a view for explaining a process when the cap of FIG. 1 is removed from the container mouth portion.

  1 to 3, the resin cap 4 of the present invention roughly includes a top plate portion 1 and a skirt wall 2. An inner ring 3 is provided on the inner surface of the top plate portion 1 so as to extend downward with a gap from the skirt wall 2. On the other hand, the skirt wall 2 hangs down from the periphery of the top plate portion 1, and a plurality of locking undercuts 5 are provided at regular intervals on the inner wall surface at the lower end thereof. That is, as clearly shown in FIG. 3, the cap 4 is fixed to the container mouth by fitting the container mouth 50 into the space between the skirt wall 2 and the inner ring 3. Yes, the cap 4 is firmly fixed to the container mouth 50 by engaging the locking undercut 5 with the jaw 51 formed on the outer surface of the container mouth.

  Moreover, in order to ensure sufficient sealing performance, the outer surface of the inner ring 3 is slightly bulged outwardly, and the most outwardly bulged portion serves as a seal point P on the inner surface of the container mouth portion 50. It comes to adhere firmly (refer FIG. 3). Further, the inner surface of the inner ring 3 is formed to be slightly inclined toward the skirt wall 2 side, thereby facilitating die cutting during molding. Further, as understood from FIG. 1, a thin portion 3a is formed in the vicinity of the base portion of the inner ring 3, and the thin portion 3a is easily bent outward or inward with the thin portion 3a as a fulcrum. . That is, by making the inner ring 3 bend easily, the container mouth portion 50 can be easily fitted (plugged) into the space between the skirt wall 2 and the inner ring 3, and the cap 4 from the container mouth portion 50 can be removed. Removal (opening) can be easily performed. In the above aspect, the thin portion 3a is formed in the vicinity of the base portion of the inner ring 3 (joint portion between the top plate portion 1 and the inner ring 3), but the base portion of the inner ring 3 itself is made thin. It is also possible to use it as a fulcrum for deformation of the inner ring 3.

  Furthermore, an annular small protrusion 7 is formed on the inner surface of the top plate portion 1 at a position between the inner ring 3 and the skirt wall 2. That is, when the container mouth portion 5 is fitted into the space between the inner ring 3 and the skirt wall 2, the seal point P on the outer surface of the inner ring 3 comes into close contact with the inner surface of the container mouth portion 50, and at the same time, Since the small protrusions 7 are in close contact with the upper end surface of the container mouth portion 50, the sealing performance is further improved.

  On the other hand, a bowl-shaped opening tab 10 is provided on the outer wall surface at the lower end of the skirt wall 2. The opening tab 10 is hooked with a finger and lifted upward to remove the cap 4 attached to the container mouth and perform opening. At this time, a protrusion 10 a is provided on the lower surface peripheral portion of the opening tab 10 so that the finger is easily caught. Further, in order to increase the strength of the opening tab 10, a plurality of triangular ribs 10 b that connect the upper surface of the opening tab 10 and the skirt wall 2 are provided. In particular, as shown in the bottom view of FIG. 2, the score 11 extends upward from below along the both side surfaces of the opening tab 10 on the skirt wall 2 on both sides of the opening tab 10. By forming the score 11 as described above, the opening tab 10 can be easily lifted upward, and the opening operation of the cap 4 with the opening tab 10 can be easily performed.

  In the present invention, the height d (seal portion height d) from the inner surface of the top plate portion 1 on the inner surface side of the inner ring 3 to the maximum outer diameter portion (seal point P) of the outer surface of the inner ring 3 is from the top surface to the bottom surface. The height dB at the opening fulcrum portion B that is 180 degrees away from the portion A corresponding to the center portion of the opening tab 10 when viewed is relatively lower than the height dA at the portion A. Yes. That is, as understood from FIGS. 1 and 3, the seal height d is gradually increased from the opening fulcrum B toward the portion B corresponding to the center of the opening tab 10, and the opening fulcrum The length d at B is the lowest. Accordingly, the seal point P of the inner ring 3 is at the shallowest position on the side of the opening fulcrum B, and gradually becomes deeper toward the portion A corresponding to the center of the opening tab 10. As a result, when the opening tab 10 of the cap 4 is lifted and the opening operation is performed, the inner ring 3 is quickly deformed inward on the opening fulcrum B side as shown in FIG. The close contact between the inner surface of the container mouth part 50 and the seal point P is released, and the tightening of the container mouth part 50 by the inner ring 3 is relaxed. Therefore, the cap 4 can be easily detached from the container mouth portion 50, and excellent detachability can be ensured.

  For example, when the seal portion height d at the opening fulcrum B is equal to the height at the portion A corresponding to the center side of the opening tab 10, as shown in FIG. Even when it is lifted, on the opening fulcrum B side, the close contact between the seal point P of the inner ring 3 and the inner surface of the container mouth 50 is not released, and the tightening of the container mouth 50 by the inner ring 3 is not relaxed, Accordingly, the cap 4 is firmly held by the container mouth portion 50 on the opening fulcrum portion B side, and it becomes difficult to remove the cap 4 from the container mouth portion 50. Thus, if the cap 4 is not far apart, the unsealing tab 50 must be lifted upward with a large force, so that the cap 4 is removed from the container mouth 50 at a stroke. Inconvenience such as flying easily occurs.

  Further, in the case where the seal part height d is lowered as a whole, the position of the seal point P becomes shallow as a whole, so that the sealing performance is not only impaired by a slight deformation of the inner ring 3, Since the inner ring 3 itself is difficult to bend, when opening the cap 4, a large force is required to lift the unsealing tab 10 first, making it difficult to open and opening the cap 4 to the container mouth 50. There is also a risk that it will be difficult to perform the stoppering (fitting into the container opening 50).

  However, according to the present invention, the height at the opening fulcrum B of the seal portion height d is relatively lower than that of the opening tab 10 side, so that not only excellent separation property can be secured, but also the opening is achieved. Since the seal portion height d at the portion A located on the center side of the tab 10 is set high, the sealing performance is not impaired by slight deformation of the inner ring 3, and when plugging, First, the seal point P of the inner ring is in close contact with the inner surface of the container 50 at the portion A corresponding to the center portion of the opening tab 10, and the seal point P is directed toward the inner surface of the container 50 in order toward the opening fulcrum B side. And adhere closely. In this way, since the container opening 50 is fitted, the stopper can be easily reached.

  In the present invention described above, the degree of lowering the seal portion height d at the opening fulcrum B of the inner ring 3 as compared to the opening tab 10 side should be determined by the position of the seal point P. The ratio (dB / dA) between the seal part height dB on the fulcrum part B side and the seal part height dA on the part A on the opening tab 10 side is set to be in the range of 0.5 to 0.9. It is good to do. That is, when this ratio (dB / dA) is close to 1, the effect of lowering the height at the opening fulcrum B of the inner ring 3 is not sufficiently exhibited, the separation property cannot be increased, and not much If it is small, inconveniences such as looseness of the cap 4 and a decrease in sealing performance are likely to occur.

In the present invention, as shown in the bottom view of FIG. 2, the pair of first scores 20 and 20 are symmetrically formed on the skirt wall 2 with the opening fulcrum B as the center. . The first scores 20, 20 extend upward from the lower end of the skirt wall 2, and the straight line Y connecting the first score 20 and the cap 4 center O, the opening fulcrum B, and the cap 4 center O The angle θ ₁ formed by the straight line X connecting the two is set to a range of 15 to 45 degrees, particularly 25 to 35 degrees. That is, when the first scores 20 and 20 are provided at such positions, when the opening tab 10 is lifted upward as shown in FIG. 4, the cap 4 moves upward with the first scores 20 and 20 as fulcrums. The opening fulcrum B where the cap 4 is held by the container mouth portion 50 is present at the center thereof, so that the pulling force by lifting the opening tab 10 is concentrated on the opening fulcrum B. In addition, the holding force in the opening fulcrum part B side region is reduced, and in this part B, the cap 4 can be easily detached from the container mouth part 50.

In the first scores 20 and 20 as described above, if the angle θ ₁ is smaller than the above range, the interval between the first scores 20 and 20 is narrowed. The tensile force is not effectively concentrated on the unsealing fulcrum part B, and the holding force in the unsealing fulcrum part B side region is not sufficiently reduced, and the opening from the container mouth part 50 of the cap 4 on the unsealing fulcrum part B side becomes insufficient. The effect of easily removing can not be expressed sufficiently. Further, when the angle θ ₁ is larger than the above range, the distance between the first scores 20 and 20 becomes too wide. In this case, the pulling force by lifting the opening tab 10 is also effective. Therefore, it does not concentrate on the opening fulcrum part B, and the holding force in the opening fulcrum part B side region is not sufficiently reduced, and the detachability of the cap 4 from the container mouth part 50 on the opening fulcrum part B side is also reduced. It is not possible to sufficiently develop the effect of easily performing the process.

  Further, in the present invention, a pair of second scores 21 and 21 are provided symmetrically on the skirt wall 2 around the opening fulcrum B on the outer side of the first scores 20 and 20 as described above. This is preferable, and the removal of the cap 4 from the container mouth portion 50 at the opening fulcrum portion B can be further improved more easily. That is, when the opening tab 10 is lifted upward as shown in FIG. 4, the cap 4 is first bent upward with the second scores 21 and 21 as fulcrums, and further lifted, the first score 20, It will be greatly bent upward with 20 as a fulcrum. An opening fulcrum B where the cap 4 is held by the container mouth 50 is present at the center of the second scores 21 and 21 and the first scores 20 and 20, and the opening tab 10 is lifted up. And the holding force in the opening fulcrum part B side region is also reduced, so that the cap 4 can be removed from the container mouth part 50 at the opening fulcrum part B more easily. Will be able to do.

The second scores 21 and 21 are preferably formed in a region opposite to the opening tab 10, and a straight line Z connecting the second score 21 and the center 4 of the cap 4 and the opening fulcrum B angle theta ₂ is 70 ° to 90 ° formed between a straight line X connecting the cap 4 center O, it is preferable in particular in the range of 80 to 90 degrees. That is, when the angle theta ₂ is out of the above range, insufficient effect to concentrate the tensile force of lifting the opening tab 10 in the unsealing fulcrum B, to sufficiently exhibit the effect of the second score 21 I can't.

The above-described resin cap 4 of the present invention is applied to a relatively wide-mouthed container such as a milk bottle, and the material thereof is not particularly limited, and is formed by integral molding such as injection molding or compression molding using various plastics. However, in general, it should be formed from polyethylene from the viewpoint of ensuring good sealing properties with a short height, and most preferably a high density of 0.950 g / cm ³ or more. It is formed of density polyethylene. That is, the cap 4 made of high-density polyethylene has moderate flexibility and exhibits good adhesion to the container mouth 50, and at the same time has higher rigidity than the low-density polyethylene. The container opening 50 fitted between the skirt wall 2 and the skirt wall 2 can be securely held, and the cap 4 can be made thin. Therefore, even if the cap 4 is thin, it is possible to effectively prevent the cap 4 from dropping off from the container mouth portion 50 due to deformation of the inner ring 3, and to maintain high sealing performance. In addition, when the conventionally known resin cap 4 is formed of high-density polyethylene, as shown in FIG. 4, when the opening tab 10 is lifted to open the cap, the cap 4 is firmly on the opening fulcrum B side. Although it will be held by the container mouth 50 and the separation of the wrinkles is considerably bad, in the present invention, this wrinkle separation can be increased by adjusting the length of the inner ring 3, so that the disadvantage of the high density polyethylene cap is effective. Can be avoided and the advantages can be utilized to the maximum.

The sectional side view which shows an example of the resin cap of this invention. The bottom view of the cap of FIG. The sectional side view which shows the cap of FIG. 1 with a container opening part. The figure for demonstrating the process when removing the cap of FIG. 1 from a container opening part.

Explanation of symbols

1: Top plate part 2: Skirt wall 3: Inner ring 10: Opening tab 20: First score 21: Second score 50: Container mouth part B: Opening fulcrum part

Claims (5)

It consists of a top plate portion and a skirt wall that hangs downward from the periphery of the top plate portion, and an outer surface of the skirt wall is formed with a hook-like opening tab that protrudes outward, and on the inner surface of the top plate portion A resin cap that is formed with an inner ring extending downward from the skirt wall at a distance, and a container mouth portion is fitted into a space between the inner ring and the skirt wall and fixed to the container mouth portion. ,
On the outer surface of the inner ring, a portion bulging outward is formed,
The height from the inner surface of the top plate portion to the maximum outer diameter portion of the outer surface of the inner ring is the height at the opening fulcrum portion that is 180 degrees away from the portion corresponding to the center portion of the opening tab when viewed from the top surface to the bottom surface. The resin cap is characterized in that it is formed relatively lower than the height of the portion corresponding to the center of the opening tab.   The height from the inner surface of the top plate portion to the maximum outer diameter portion of the outer surface of the inner ring gradually increases from the opening fulcrum portion toward a portion corresponding to the center portion of the opening tab. Resin cap. A pair of first scores are symmetrically formed on the skirt wall with the opening fulcrum portion as the center, and a straight line connecting the first score and the cap center and a straight line connecting the opening fulcrum portion and the cap center. resin cap according to claim 1 or 2 angle theta ₁ is in the range of 15 to 45 degrees Doo forms. A pair of second scores are symmetrically formed on the skirt wall with the opening fulcrum portion as the center, and a straight line connecting the second score and the cap center and a straight line connecting the opening fulcrum portion and the cap center. The resin cap according to claim 3, wherein an angle θ ₂ formed by is in a range of 70 to 90 degrees. The resin cap according to any one of claims 1 to 4, wherein the resin cap is made of high-density polyethylene having a density of 0.950 g / cm ³ or more.

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