JP2011111218A - Spout stopper and packaging container - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a spout stopper which does not generate cracks even when being welded, and to provide a packaging container equipped with the spout stopper. <P>SOLUTION: A spout 4 is manufactured by being molded of a low density polyethylene (LDPE). As the LDPE, one having a density of 0.895 g/cm<SP>3</SP>or higher and less than 0.905 g/cm<SP>3</SP>, having a flexural modulus of 180 MPa or higher and less than 220 MPa, having a numeral average molecular weight (Mw) of 200,000 or higher and less than 250,000, and having a value (Mw/Mn), the numeral average molecular weight divided by the weight average molecular weight, of 6 or higher and 7 or lower is used. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a spout stopper attached to an opening of a paper pack or the like and a packaging container to which a spout stopper is attached.

  As packaging containers for packaging liquid contents such as beverages, for example, in consideration of usability during use, a paper container or the like provided with a spout stopper is widely used. In general, the spout stopper includes a cylindrical spout having a flange and a cap attached to the spout. Spouts that are integrally molded from low-density polyethylene (LDPE) are widely used, and are fitted from the inside so as to pass through the opening formed in the packaging container. The inner surface of the container is thermally welded.

Japanese Patent Laid-Open No. 11-227817 JP 2000-296865 A JP 2003-72817 A Japanese Patent Laid-Open No. 2004-67101

  In general, an ultrasonic vibration welding method is often used to thermally weld the spout stopper. In the ultrasonic vibration welding method, thermal welding is performed by applying fine ultrasonic vibration in a state where the joint surfaces of the paper container and the spout are overlapped. However, when ultrasonic vibration is applied, a crack may occur in a groove portion or the like that partitions a part of the partition wall connected to the pull ring.

  Therefore, an object of the present invention is to provide a spout stopper that does not crack even if it is welded, and a packaging container including the spout stopper.

The present invention relates to a spout stopper that is welded to an opening of a liquid packaging container. The spout stopper includes a spout made of low-density polyethylene and a cap attached to the spout. Low density polyethylene has a density of 0.895 g / cm ³ or more and less than 0.905 g / cm ^3.

  When the spout stopper of the present invention is used, vibration can be absorbed by the characteristics of the material of the spout during ultrasonic welding between the spout stopper and the paper container, and the spout cracking can be effectively suppressed.

Packaging container according to an embodiment of the present invention Sectional drawing along the II-II line of the packaging container shown in FIG.

(Embodiment)
FIG. 1 is a perspective view of a packaging container according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view taken along line II-II of the packaging container shown in FIG.

  A packaging container 1 according to an embodiment of the present invention is obtained by welding a spout stopper 3 to an opening of a paper container 2. The spout 3 includes a spout 4 and a cap 5 that is screwed onto the spout 4. The spout 4 includes a cylindrical side wall 41, a flange-like connecting portion 42 provided on the entire circumference from the lower end of the side wall 41 toward the outside, and four paper pressers provided on the outer surface of the side wall 41 at equal intervals in the circumferential direction. Projection 43, a concave meat stealing portion 44 formed on the end surface on the lower end side of the side wall 41, a partition wall 46 for closing the inner surface of the side wall 41, and a lower surface of the partition wall 46 on the entire periphery. And a pull ring 48 connected to the upper surface of the partition wall 46. At the time of use, by pulling the pull ring 48 in the upward direction in the drawing, a part of the partition wall 46 surrounded by the thin portion 47 can be pulled out, and the spout 4 can be put through. The spout 4 is integrally molded using LDPE obtained by mixing two or more types of low density polyethylene (LDPE) having different molecular weight compositions at a predetermined ratio. The cap 5 is formed using polypropylene (PP) or the like.

Here, as the molding material of the spout 4, the density (measured value) is 0.895 g / cm ³ or more and 0.905 g / cm ³ less than the material is used. As described above, when the spout 4 is welded to the paper container 2 by the ultrasonic vibration welding method, vibration is applied to the spout 4. By using LDPE having a composition satisfying this condition, the spout 4 is varied depending on the characteristics of the material. The vibration applied to the can be absorbed. As a result, it is possible to effectively suppress cracking at a weak portion such as the thin portion 47 that is a thin portion that partitions a part of the partition wall 46. On the other hand, when the density is less than 0.895 g / cm ³ , a waxy component appears on the surface of the spout and the molded product cannot be used as a product substantially. On the contrary, when the density is 0.905 g / cm ³ or more, the probability of occurrence of cracks during welding increases.

  Moreover, it is preferable that the bending elastic modulus (measured value) of this LDPE is 180 MPa or more and less than 220 MPa. If the flexural modulus is within this range, the rigidity required for the spout 4 when using the packaging container 1 can be sufficiently secured. On the other hand, when the flexural modulus is less than 180 MPa, the rigidity of the spout 4 is insufficient, and conversely, when the flexural modulus is 220 MPa or more, a part of the partition wall 46 is pulled out by pulling the pull ring 48 to remove the spout 4. When opening, the thin part 47 becomes difficult to cut (cutting property worsens).

  Furthermore, it is preferable that the weight average molecular weight (Mw) (actual value) of this LDPE is 200000 or more and less than 250,000. If Mw is within this range, the shape of the spout can be maintained during welding (the spout 4 does not melt). On the other hand, when Mw is less than 200000, spout 4 melts during welding, and conversely, when Mw is 250,000 or more, due to the high vibrational energy applied to spout 4 during welding, There is a high possibility that cracks and the like will occur.

  Furthermore, it is preferable that a value (Mw / Mn) (actual value) indicating a molecular weight distribution obtained by dividing the weight average molecular weight of the LDPE by the number average molecular weight is 6 or more and 7 or less. When Mw / Mn is within this range, the ratio of the low molecular weight component in the LDPE decreases, and partial melting of the spout 4 due to the low molecular weight component during welding can be suppressed. On the other hand, if Mw / Mn exceeds 7, partial melting occurs in the thin-walled portion 47 of the spout 4 due to an increase in the ratio of low molecular weight components. Conversely, when Mw / Mn is less than 6 Since the composition distribution of molecular weight components approaches uniform, vibration absorption due to the inclusion of a plurality of molecular weight components decreases.

  As described above, the spout 4 can be welded to the paper container 2 without causing cracking or melting of the spout 4 itself by producing by using LDPE having the above physical property values.

  In addition, in this embodiment, although the spout employ | adopts the structure mentioned above, if it is a shape which functions as a spout of a packaging container, it will not be specifically limited to this.

  Moreover, in this embodiment, the cap employs a structure that can be attached to the spout, but there is no particular limitation as long as the cap can be opened and closed. For example, a structure in which the outer surface of the spout is simply covered with the inner surface of the cap or a structure in which the cap and the spout are fitted may be employed.

  Furthermore, in this embodiment, although the paper container is used, it will not be specifically limited if it can enclose the liquid content. For example, a resin container such as a pouch or a gusset bag may be used.

  Hereinafter, examples in which the present invention is specifically implemented will be described.

  The spouts according to Examples 1 to 3 and Comparative Examples 1 and 2 each have the same structure as that shown in FIG. 2, and only the physical property values of LDPE, which is a spout molding material, are different. The LDPE used for molding the spouts according to Examples 1 to 3 was prepared by mixing two different types of LDPE. Specifically, LDPE having a high melt index (MI) and a low elastic modulus and LDPE having a low MI and a high elastic modulus were mixed at different ratios to produce LDPE used in Examples 1 to 3.

Example 1
The spout according to Example 1 has a density of 0.898 g / cm ³ , a flexural modulus of 200.8 MPa, Mw of 218000, Mw / Mn of 6.4, MI of 9.2 g / min, and a melting point of 108.3. It produced by shape | molding using LDPE of degreeC.

(Example 2)
The spout according to Example 2 has a density of 0.899 g / cm ³ , a flexural modulus of 186.7 MPa, Mw of 219000, Mw / Mn of 7.0, MI of 17.3 g / min, and a melting point of 107.7. It produced by shape | molding using LDPE of degreeC.

(Example 3)
The spout according to Example 3 has a density of 0.900 g / cm ³ , a flexural modulus of 192.9 MPa, Mw of 227000, Mw / Mn of 6.6, MI of 7.5 g / min, and a melting point of 108.0. It produced by shape | molding using LDPE of degreeC.

(Comparative Example 1)
The spout according to Comparative Example 1 has a density of 0.908 g / cm ³ , a flexural modulus of 165.0 MPa, Mw of 304000, Mw / Mn of 8.3, MI of 7.0 g / min, and a melting point of 107.0. It produced by shape | molding using LDPE of degreeC.

(Comparative Example 2)
The spout according to Comparative Example 2 has a density of 0.910 g / cm ³ , a flexural modulus of 195.0 MPa, Mw of 270000, Mw / Mn of 7.0, MI of 7.0 g / min, and a melting point of 107.0. It produced by shape | molding using LDPE of degreeC.

  Twenty spouts according to Examples 1 to 3 and Comparative Examples 1 and 2 were prepared and used as samples for an ultrasonic durability test. Then, each sample is stored at 5 ° C., and thereafter the condition is that the frequency is 20 kHz, the vibration time is 0.2 seconds, the amplitude is 80 μm, and the vibration energy is 240 J. Was increased to increase the possibility of cracking in the thin part of the spout, etc.) and was welded to the paper container. Then, the occurrence of cracking in the sample after welding was visually observed to confirm the number of samples in which cracking occurred.

  Table 1 summarizes the physical property values of LDPE, which is a molding material, and the results of ultrasonic durability tests for the spouts according to Examples 1 to 3 and Comparative Examples 1 and 2. From the results of Table 1, it was confirmed with a significant difference that the spouts according to Examples 1 to 3 had fewer samples with cracks than the spouts according to Comparative Examples 1 and 2. In addition, since the ultrasonic durability test performed was performed under severe conditions (amplitude is 80 μm (usually 50 to 60 μm), frequency is 20 kHz, and vibration energy is 240 J (usually 200 J)) compared to normal welding, the example In the spouts according to 1 to 3, it is considered that the occurrence of cracks is remarkably suppressed as compared with the spouts according to Comparative Examples 1 and 2 during normal welding.

  The present invention can be used for a spout stopper that is ultrasonically welded to an opening of a paper container or the like that encloses a liquid.

DESCRIPTION OF SYMBOLS 1 Packaging container 2 Paper container 3 Outlet plug 4 Spout 41 Side wall 42 Connection part 43 Protrusion 44 Meat stealing part 45 Rib 46 Partition 47 Thin part 48 Pull ring

Claims (4)

A spout stopper welded to the opening of the liquid packaging container,
A spout made of low density polyethylene,
A cap attached to the spout;
The low density density polyethylene is 0.895 g / cm ³ or more and less than 0.905 g / cm ^3, the spout stopper.   The spout stopper according to claim 1, wherein the low-density polyethylene has a flexural modulus of 180 MPa or more and less than 220 MPa.   The spout according to claim 1 or 2, wherein the number average molecular weight of the low density polyethylene is 200000 or more and less than 250,000, and a value obtained by dividing the number average molecular weight by the weight average molecular weight is 6 or more and 7 or less. plug. The spout stopper according to any one of claims 1 to 3,
A packaging container comprising a paper container to which the spout stopper is welded.

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