JP2009154941A - Plastic cap with improved cleaning characteristic - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance the cleaning characteristic of a threadedly engaged plastic cap having a threadedly engaged cap having screw threads engaging with a wall of a container mouth on an inner surface of a skirt-like side wall of the cap, and surely preventing a stored liquid from adhering to and remaining on the outer surface of the wall of a container mouth. <P>SOLUTION: A plurality of circumferential extending cleaning slits 20 are spaced apart and formed in a circumferential direction of a skirt-like side wall 3 of a cap at a location where they are positioned higher than screw thread 11 threadedly engaged with a wall of a container mouth 50, and the inner surface of the skirt-like side wall 3 where the cleaning slits 20 are formed is formed with vertical ribs 30 extending in a vertical direction to pass through both ends of each of the cleaning slits 20 in their circumferential direction or between them. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a screw-engagement type plastic cap, and more specifically, a thread that engages with a container mouth wall is formed on the inner surface of a skirt-like side wall of the cap. It is related with the screw engagement type plastic cap hold | maintained by the container opening part by this.

  Screw-engaged plastic caps are used for various purposes, and are widely used as caps for containers filled with beverages such as carbonated drinks, fruit drinks, and teas.

  Such a screw engagement type cap has a thread that engages with the thread formed on the outer surface of the container mouth wall on the inner surface of the skirt-shaped side wall that descends from the periphery of the cap top plate. After filling the content liquid, the container content liquid may spill out before the capping process is completed, and may adhere to the outer surface of the container mouth wall. When the cap is fastened to the container in such a state, the opening torque of the cap increases due to the generation of so-called sugar cement, and it may be difficult to open the cap. In particular, when the liquid adheres to the thread on the outer surface of the container mouth wall, such a tendency of increasing the opening torque is remarkable. Moreover, even if the content liquid does not contain sugar, when the cap is opened, there is a problem in that tea astringency or the like remains on the outer surface of the container mouth wall and the appearance of the container is impaired. Moreover, it is not preferable also in terms of hygiene. For this reason, a slit for cleaning is formed in the upper part of the skirt-shaped side wall, and cleaning water is allowed to enter in a state where the cap is fastened to the container mouth wall, and through the slit, the skirt-shaped side wall of the cap and the container mouth The content liquid adhering to the outer surface of a container mouth part wall is removed by pouring washing water between the outer surface of a part wall (refer patent documents 1 and 2).

JP-A-11-208693 JP-A-2005-255233

  However, recently, a large amount of content liquid has been filled in the container so that the head space of the container has a small volume, and the liquid level of the content liquid has risen to the upper end of the container mouth wall or in the vicinity thereof. The content liquid is likely to spill out during the process until the cap is fastened or when the cap is fastened, and a relatively large amount of the content liquid adheres to the outer surface of the container mouth wall (particularly the outer surface of the screw portion). In many cases, even if a slit for cleaning is provided on the skirt-shaped side wall, there is a problem that the content liquid adhering to the outer surface of the container mouth wall cannot be sufficiently removed.

  Accordingly, an object of the present invention is to clean a screw engaging plastic cap in which a screw engaging cap provided with a thread for engaging with a container mouth wall is provided on the inner surface of a skirt-like side wall of the cap. It is an object of the present invention to provide a cap that can further enhance the performance and reliably prevent the content liquid from remaining on the outer surface of the container mouth wall.

According to the present invention, a top plate portion and a skirt-like side wall descending from the periphery of the top plate portion are provided, and a screw thread is formed on the inner surface of the skirt-like side wall so as to be screw-engaged with the outer surface of the container mouth wall. In plastic caps,
In the skirt-shaped side wall, a plurality of cleaning slits extending in the circumferential direction at a portion located above the thread are formed at intervals in the circumferential direction,
On the inner surface of the skirt-shaped side wall of the portion where the cleaning slit is formed, there are formed longitudinal ribs extending in the longitudinal direction so as to pass through both ends of the circumferential direction of each cleaning slit or between them. A characteristic plastic cap is provided.

In the present invention,
(1) A plurality of the vertical ribs are formed at equal intervals in the circumferential direction, and the cleaning slit has the following conditions:
A ≧ B
In the formula, A indicates the circumferential width of each cleaning slit,
B shows the interval between adjacent vertical ribs,
It is formed by post-processing after cap molding so as to satisfy
(2) The cleaning slit has the following conditions:
A ≧ B + C
In the formula, A indicates the circumferential width of each cleaning slit,
B indicates the interval between adjacent vertical ribs;
C indicates the circumferential width of each vertical rib,
It is formed by post-processing after cap molding so as to satisfy
Is preferred.

  In the cap of the present invention, when cleaning water is introduced from the outer surface of the cap and cleaning is performed, the cleaning water is introduced into the cap from the plurality of cleaning slits provided on the skirt-shaped side wall and flows down, and the container mouth wall It is possible to remove the content liquid adhering to the upper part of the thread or the upper part thereof, but at the same time providing such a cleaning slit, the inner surface of the skirt-like side wall passes through the opening on the inner surface side of each cleaning slit. It is an important feature that vertical ribs are formed.

  That is, as will be understood from the comparative example described later, it is not possible to perform sufficient cleaning simply by providing a cleaning slit. The reason for this has not been clearly elucidated, but the cleaning water that has flowed in from the cleaning slit probably does not flow down sufficiently due to the action of surface tension, etc., and stays in the space near the part where the cleaning slit is formed. It is thought that it is because of it. However, according to the present invention, by providing a longitudinal rib so as to pass through the opening on the inner surface side of the cleaning slit, this longitudinal rib functions as a guide for the cleaning water introduced from the cleaning slit, so that retention of the cleaning water is effective. As a result, the cleaning water flows smoothly into the cap, and as a result, the cleaning power is further enhanced as shown in the examples described later, and the content attached to the outer surface portion of the container mouth wall This makes it possible to remove the liquid reliably.

The present invention will be described below based on specific examples shown in the accompanying drawings.
FIG. 1 is a half sectional side view of a plastic cap of the present invention,
FIG. 2 is a cross-sectional view taken along the line II of FIG.
FIG. 3 is a view showing a side cross section of the main part of the cap of FIG. 1 together with the container mouth wall,
4 is an enlarged view of a cross-sectional side view of the main part of the cap of FIG.
FIG. 5 is an enlarged plan sectional view of a main part of the cap of FIG.
FIG. 6 is a half sectional side view showing another embodiment of the plastic cap of the present invention.

  With reference to FIGS. 1 to 3, the plastic cap of the present invention is composed of a top plate portion 1 and a skirt-like side wall 3 depending from the peripheral portion of the top plate portion 1.

  An inner ring 5 is formed on the inner surface of the top plate portion 1 so as to extend downward with a gap from the skirt-shaped side wall 3. An outer ring having a shorter height than the inner ring 5 is formed outside the inner ring 5. A ring 7 is formed. Further, a base portion 8 that protrudes inward is formed at the base portion of the inner surface of the outer ring 7, and a circumferential small protrusion 9 is formed between the inner ring 5 and the outer ring 7. Has been.

  On the other hand, a thread (female thread) 11 is formed on the inner surface of the skirt-shaped side wall 3, and notches 12 extending in the height direction of the cap are formed in the thread 11 at appropriate intervals. Has been. This notch 12 serves as a flow path for cleaning water described later.

  Moreover, a slit 15 for breaking is formed in the lower part of the screw 11 so as to leave a plurality of bridges 13 by cutting from the outer surface. That is, the breaking slit 15 is formed over the entire circumference, whereby a TE band 17 is formed at the lower part of the skirt-like side wall, and the TE band 17 is formed by the bridge 13 on the skirt-like side wall 3. It has become a series. Also, upward flap pieces 19 are provided on the inner surface of the TE band 17 at appropriate intervals.

  Further, as shown in FIG. 3, the outer surface of the mouth wall 50 of the container to which the cap is fastened is screw-engaged with a thread (female screw) 11 provided on the skirt-like side wall 3. A screw (male screw) 51 is provided, and a jaw 53 is formed below the screw 51.

  That is, when the cap is put on the container mouth wall 50 and rotated in the closing direction, the cap 11 is fastened by screw engagement with the threads 11 and 51, and the upper end portion of the container mouth wall 50 is connected to the inner ring 5. A seal is secured by entering the space between the outer ring 7 and the outer surface of the inner ring 5 closely contacting the inner surface of the container mouth wall 50. Further, the inner surface of the outer ring 7 is in close contact with the upper end portion of the outer surface of the container mouth wall 50, and therefore the inner ring 5 and the outer ring 7 rotate concentrically when the cap is closed or opened. This means that the close contact (that is, the sealing property) between the inner ring 5 and the container mouth wall 50 is effectively maintained. That is, when closing the plug, the sealing performance can be secured stably. When opening the cap, the seal does not break immediately due to the rotation of the cap, but after a certain degree of rotation, the seal is broken. The function of the TE band 17 can be sufficiently exerted (the seal breakage can be prevented before the bridge breaks). In the cap having the above structure, when an external force is accidentally applied from the upper part, the circumferential small protrusion 9 comes into contact with the upper end of the container mouth wall 50, and as a result, the external force from the upper part is reduced. Therefore, deformation of the cap can be effectively avoided.

  The TE band 17 has a so-called tamper evidence (opening history certification) function, and is used for prevention of mischief and quality assurance of contents. That is, when the cap fastened to the container mouth wall 50 is rotated in the opening direction, the cap rises along the container mouth wall 50, and is provided on the inner surface of the TE band 17 with the rise. The flap piece 19 is in contact with the lower surface of the jaw 53 formed on the outer surface of the container mouth wall 50, and therefore the rise of the TE band 17 is restricted. As a result, when the cap continues to rotate in the opening direction, the bridge 13 connecting the TE band 17 is broken, and the TE band 17 is peeled off from the cap. As a result, it is shown that the cap from which the TE band 17 has been peeled has already been opened, or that the seal has already been broken, and the general consumer can recognize the opening history. It is.

  Also, the skirt-like side wall 3 is provided with a plurality of cleaning slits 20 extending in the circumferential direction (six in this example as shown in FIG. 2) at intervals in the circumferential direction. Then, the cleaning water is introduced into the cap fastened to the container mouth wall 50 by spraying the cleaning water from above the cap by shower or the like, and the outer surface of the container mouth wall 50 is cleaned. .

  In the present invention, the cleaning slit 20 may be provided above the screw (female screw) 11, but it is particularly preferable that the cleaning slit 20 be positioned above the lower end of the outer ring 7.

  That is, in a container filled with the content liquid, the content liquid may spill out and adhere to the outer surface of the mouth wall 50. When a cap is fastened to such a container, the cap If there is a content liquid adhering to the inner surface of the skirt-shaped side wall 3, particularly between the threads 11 and 51, it may be difficult to open the plug due to the production of sugar cement or the like. In particular, recently, since there is a tendency to fill a large amount of the content liquid so as not to leave a head space in the container, the content liquid is spilled when the cap is fastened, and such content liquid tends to adhere. Accordingly, the cleaning slit 20 as described above is provided, and pressurized cleaning water (for example, shower water) is sprayed from the outer surface of the cap in a state where the cap is fastened, and the inside of the cap (container mouth wall 50 is discharged from the cleaning slit 20. Between the skirt-like side wall 3 and the skirt-like side wall 3), and the attached content liquid is washed away. The washing water passes between the threads 11 and 51, passes through the notch 12 formed in the threads 11, and flows downward. When cleaning is performed in this way, even if the cleaning between the threads 11 and 51 is sufficiently performed, in particular, the vicinity of the lower end of the outer ring 7 (for example, the thread 51 formed on the container mouth wall 50). Of the top surface of the uppermost part) is likely to be insufficiently cleaned. This is because a recess is formed in the lower end portion of the outer ring 7 and the washing water does not spread sufficiently. However, if the cleaning slit 20 is provided above the lower end of the outer ring 7, the content liquid adhering to such a portion can be reliably cleaned and removed.

  The size and number of the cleaning slits 20 are formed so that a sufficient amount of cleaning water is evenly introduced into the cap without reducing the strength of the cap. Is about 0.01 to 0.10 mm, the circumferential width A is about 2.0 to 5.0 mm, and the distance D between adjacent cleaning slits 20 is about 5.0 to 20.0 mm. Thus, it is preferable to form the skirt-like side wall 3 evenly in the circumferential direction with a number of about 4 to 8.

  In the present invention, by setting the position of the cleaning slit 20 above the lower end of the outer ring 7 as described above, the cleaning water can be sufficiently distributed near the lower end of the outer ring 7. However, the cleaning slit 20 is provided at such a position, and at the same time, as shown in FIG. 4 and FIG. Vertical ribs 30 are provided so as to pass through openings on the inner surface side of the slit 20.

  As already described, the cleaning water stays in the space in the vicinity of the cleaning slit 20 only by providing the cleaning slit 20, and as a result, a sufficient amount of the cleaning water does not flow down and the cleaning power is improved. Is not enough. However, as described above, each of the cleaning slits 20 is provided with the vertical ribs 30 so as to pass through the opening portions on the inner surface side thereof, so that the cleaning water introduced from the cleaning slits 20 by the vertical ribs 30 is provided. The water can be effectively prevented from staying, the washing water can flow smoothly, the washing power can be further enhanced, and the content liquid adhering to the outer surface portion of the container mouth wall 50 can be reliably removed. This makes it possible to more effectively prevent a decrease in openability due to sugar cement or the like.

  In the present invention, the vertical rib 30 does not block the flow of the cleaning water through the cleaning slit 20, and does not block both ends of the opening portion on the inner surface side of each cleaning slit 20 or a region between the both ends. The size and number of the ribs 30 are not particularly limited as long as they pass through, but the vertical ribs 30 usually extend from the inner surface of the top plate portion 1 (the upper end is continuous with the inner surface of the top plate portion 1). (Refer to FIG. 4 etc.). That is, if a space is formed between the upper ends of the vertical ribs 30 and the inner surface of the top plate portion 1, there is a possibility that it is difficult to remove the mold during cap molding.

  Further, as shown in FIG. 4 and the like, it is sufficient that the lower end position of the vertical rib 30 is positioned at the same height as the upper end portion of the thread 11. Further, the length L in the radial direction of the vertical rib 30 is not particularly limited, but if the length L is too short, the liquid guiding effect tends to be reduced, so that the length is 0.3 mm or more, In particular, it should be 0.5 mm or more. Moreover, in the example of FIGS. 1-5, although the space is formed between the vertical rib 30 and the outer surface of the outer ring 7, the radial direction length is enlarged enough and the principal part enlarged view of FIG. As shown, the vertical rib 30 and the outer surface of the outer ring 7 may be continuous. However, if the longitudinal rib 30 and the outer ring 7 are connected, the outward deformation of the outer ring 7 is suppressed, so that the closing torque when the cap is fastened to the container mouth part slightly increases. There is. Therefore, from the viewpoint of plug-closing properties, it is preferable that the vertical ribs 30 are not connected to the outer surface of the outer ring 7 as shown in FIGS.

  Further, the circumferential width C (see FIG. 5) of the vertical ribs 30 may be of a size that does not impede the flow of cleaning water through the cleaning slit 20, and the circumferential width A of each cleaning slit 20 In general, the length is preferably 20% or less of the length of the circumferential width A, although it varies depending on the length.

By the way, the cleaning slit 20 described above is formed by post-processing (cutting) using a cutter while rotating the molded cap after molding the cap. For this reason, in order to make the vertical ribs 30 formed so as to pass through the opening on the inner surface side of the cleaning slit 20, a plurality of the vertical ribs 30 are formed at equal intervals in the circumferential direction, Conditions defined by the following formula (1):
A ≧ B (1)
In the formula, A indicates the circumferential width of each cleaning slit 20,
B shows the interval between the adjacent vertical ribs 30;
It is preferable to set the cleaning slit 20 and the longitudinal rib 30 so as to satisfy the above. By arranging the vertical ribs 30 evenly in the circumferential direction at such intervals in advance, both ends or both ends of the opening on the inner surface side of the cleaning slit 20 are always made even when post-processing is started from an arbitrary position. It can be set as the structure where the vertical rib 30 passes in the position between parts.

Moreover, in this invention, the conditions prescribed | regulated by following formula (2):
A ≧ B + C (2)
In the formula, A indicates the circumferential width of each cleaning slit,
B indicates the interval between adjacent vertical ribs;
C indicates the circumferential width of each vertical rib,
It is optimal to set the cleaning slit 20 and the longitudinal rib 30 so as to satisfy the above. That is, if the vertical ribs 30 are arranged in the circumferential direction at such intervals and sizes in advance, the vertical ribs 30 can be formed on the inner surface of the cleaning slit 20 no matter where the post-processing is started. This is because the cleaning water guiding effect of the vertical ribs 30 is exhibited to the maximum by passing through the intermediate portion instead of the both end portions on the side.

  In the above-described specific example, the inner ring 5 and the outer ring 7 are formed on the inner surface of the top plate portion 1 of the cap, and the container mouth wall 50 is inserted between the rings 5 and 7 and sealed. However, the present invention is not limited to such a one-piece cap. For example, as long as a thread is formed on the inner surface of the skirt side wall of the cap and the container mouth is attached by screw engagement, The present invention can also be applied to a two-piece cap in which a liner is provided on the inner surface of the top plate portion.

Example 1
A polypropylene resin cap (nominal diameter of 28 mm) formed with vertical ribs as shown in FIG. 6 was molded by compression molding. Thereafter, slits were formed in the cap skirt-like side wall by slitting in a slit forming process by a slit forming cutter. The specifications of this cap are as follows.

Cleaning slit 20:
Position in the center in the axial direction: Height position 2.5 mm downward from the top surface of the cap top plate part Circumferential width A: 4.0 mm
Axial width d: 0.1 mm (minimum width 0.01 mm)
Number: 6 (disposed at equal intervals in the circumferential direction)

Vertical rib 30:
Circumferential width C: 0.5 mm
Axial length: 1.6mm
(Length from the bottom of the cleaning slit to the bottom of the rib 30)
Number: 15 (disposed at equal intervals in the circumferential direction with a rib interval B of about 5 mm)

(Comparative Example 1)
A cap was prepared in exactly the same manner as in Example 1 except that no vertical rib 30 was formed.

<Evaluation experiment>
Sample for evaluation;
Fill the 350ml PET bottle with 87 ° C hot water, spray oolong tea around the bottle mouth screw part, put the cap of Example 1 and Comparative Example 1 on purpose, and wind the cap with a capping machine. Tightened.
Next, after the container was laid down and sterilized (30 seconds), the hot water shower was performed (76 ° C.-3.5 minutes → 50 ° C.-4.2 minutes → 40 ° C.-4 minutes → 35 ° C.-5.9 minutes). → 30 ° C.-2.5 minutes). The filled product was dried at room temperature for 1 day, and then the contents of the bottle were drained from the bottle and further dried in a constant temperature room at 40 ° C. for 1 day to obtain a sample for evaluation.

Evaluation methods;
In order to confirm the cap cleaning effect, the liquid adhesion contamination state of the cap screw part and the bottle screw part was confirmed for each of the 20 samples for evaluation. In the confirmation method, the degree of contamination was determined from the total number of remaining liquid deposits (number of remaining stains (number) / total) and the total length of the liquid deposits. The degree of contamination was evaluated in five stages, from 0 points (no contamination) to 4 points (many stains), and the average score was shown from the degree of each 20 stains. The results are shown in Tables 1 and 2.

液付着汚れ度合い ０点：汚れ無し
１点：汚れがネジ全周長さの１/４より短い
２点：汚れがネジ全周長さの１/４〜１/２
３点：汚れがネジ全周長さの１/２〜３/４
４点：汚れがネジ全周長さの３/４より長い

Degree of liquid adhesion dirt 0 point: No dirt
1 point: Dirt is shorter than 1/4 of the total circumference of the screw
2 points: Dirt is 1/4 to 1/2 of the screw circumference
3 points: Dirt is 1/2 to 3/4 of the total circumference of the screw
4 points: Dirt is longer than 3/4 of the total screw circumference

  In addition, when the amount of hot water entering into the cap from the slit during the hot water shower process was measured, it was found that the amount of penetration of the cap of Example 1 was about five times that of the cap of Comparative Example 1. .

The half section side view of the plastic cap of this invention. II sectional drawing of the cap of FIG. The figure which showed the principal part side cross section of the cap of FIG. 1 with the container opening part wall. The enlarged view of the principal part side cross section of the cap of FIG. FIG. 3 is an enlarged plan cross-sectional view of a main part of the cap of FIG. 2. The half cross-sectional side view which shows another form of the plastic cap of this invention.

Explanation of symbols

3: Skirt-shaped side wall 5: Inner ring 7: Outer ring 11: Cap thread 20: Cleaning slit 30: Vertical rib 50: Container mouth wall 51: Container mouth wall thread

Claims (3)

In a plastic cap comprising a top plate portion and a skirt-like side wall that descends from the periphery of the top plate portion, and an inner surface of the skirt-like side wall is formed with a thread that engages with the outer surface of the container mouth wall.
In the skirt-shaped side wall, a plurality of cleaning slits extending in the circumferential direction at a portion located above the thread are formed at intervals in the circumferential direction.
On the inner surface of the skirt-shaped side wall of the portion where the cleaning slit is formed, there are formed longitudinal ribs extending in the longitudinal direction so as to pass through both ends of the circumferential direction of each cleaning slit or between them. Characteristic plastic cap. A plurality of the vertical ribs are formed at equal intervals in the circumferential direction, and the cleaning slit has the following conditions:
A ≧ B
In the formula, A indicates the circumferential width of each cleaning slit,
B shows the interval between adjacent vertical ribs,
The plastic cap according to claim 1, which is formed by post-processing after cap molding so as to satisfy the above. The cleaning slit has the following conditions:
A ≧ B + C
In the formula, A indicates the circumferential width of each cleaning slit,
B indicates the interval between adjacent vertical ribs;
C indicates the circumferential width of each vertical rib,
The plastic cap according to claim 2, wherein the plastic cap is formed by post-processing after cap molding so as to satisfy the above.

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