JP2005289486A - Cap liner material and cap - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cap liner material and a cap which prevent a denaturalization of a drink in a bottle can and are superior in cap opening and shockproof characteristics. <P>SOLUTION: This cap liner material 10 mounted on a metallic cap which is turned to be opened comprises the first layer 11 made of a thermoplastic resin composite and the drink contacting second layer made of polyester having a 20-60 mass% degree of crystallinity. This cap 1 is provided with a top panel part 20, a peripheral wall part 30 roughly perpendicularly hanging down from the peripheral edge of the panel part 20 and the liner material the layer 11 of which contacts the inside face 21 of the panel part 20. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a liner material provided on a metal cap such as an aluminum alloy. Furthermore, it is related with the metal cap which seals a bottle can.

Bottle containers with caps sealed with metal caps (hereinafter abbreviated as caps) are widely used as containers for beverages such as soft drinks and alcoholic beverages. The type of bottled can with a cap is popular.
FIG. 5 shows a cap of the type that is rotated to open the cap. The cap 70 includes a circular top plate portion 71, a peripheral wall portion 72 substantially hanging from the periphery of the top plate portion 71, and a disk-shaped liner material 74 provided on the inner surface 73 of the top plate portion 71. have.
When sealing the bottle can with this cap, after filling the inside of the bottle can with a drink, cover the cap portion (opening portion) of the bottle can, and the cap is wrapped around the cap portion of the bottle can by capping. . At this time, the end portion of the cap portion of the bottle can is pressed against the liner material to seal the bottle can.
Here, the liner material is a resin sheet provided on the inner surface of the top plate portion of the cap, and polyolefin, elastomer, or the like is generally used as the resin.

However, when the liner material contains a polyolefin or an elastomer, when the beverage comes into contact with the liner material, a part of the beverage component may be absorbed and the beverage may be altered, for example, the flavor property may be reduced. It was.
Therefore, Patent Document 1 proposes covering a liner material containing polyethylene with a polyester film. Thus, if the liner material covered with the polyester film is used, the beverage can be prevented from coming into contact with polyethylene.
JP-A-10-194309

However, the cap described in Patent Document 1 is a type that is peeled off from the bottle can through a tab provided on the cap, and does not consider opening the cap by rotating the cap. Therefore, when the liner material described in Patent Document 1 is applied to a rotary opening type cap, although the beverage can be prevented from coming into contact with polyolefin or the like, the opening torque may be high and the opening performance may be insufficient. It was.
In addition, the bottle with a cap receives an impact during transportation, and the liner material may be damaged by the impact. However, the liner material described in Patent Document 1 has not been sufficiently considered. Therefore, the liner material described in Patent Document 1 may be damaged by impact and the sealing performance may be reduced, and the beverage inside the bottle can may be leaked.
The present invention has been made in view of the above circumstances, and can provide a cap liner material and a cap that are excellent in both openability and impact resistance, in addition to being able to prevent the deterioration of the beverage inside the bottle can. Objective.

The cap liner material of the present invention is a cap liner material provided on a metal cap that is opened by rotating,
A first layer made of a thermoplastic resin composition and a second layer made of polyester having a crystallinity of 20 to 60% by mass and in contact with a beverage are provided.
According to such a cap liner material, since the first layer can be covered with the second layer, it is possible to prevent the beverage from coming into contact with the first layer. In addition, since the polyester constituting the second layer has a specific crystallinity, absorption of the beverage components can be suppressed, and the opening torque is reduced, resulting in excellent impact resistance.
In the cap liner material of the present invention, it is preferable that a lubricant adheres to the surface of the second layer. If the lubricant adheres to the surface of the second layer, the frictional force with the bottle can can be reduced.

The cap of the present invention includes a top plate portion, a peripheral wall portion substantially hanging from the periphery of the top plate portion, and the above-described cap liner material in which the first layer is in contact with the inner surface of the top plate portion. Features.
In such a cap, the second layer of the liner material can prevent the beverage from coming into contact with the first layer containing a thermoplastic resin such as polyethylene. Further, since the polyester forming the second layer in contact with the bottle can has a specific crystallinity, the opening torque can be reduced.

  According to the present invention, the beverage inside the bottle can can be prevented from being deteriorated and the cap opening property is excellent. Moreover, since it is excellent in impact resistance, it is hard to break even if it receives an impact, and can prevent the beverage from leaking.

An embodiment of a cap liner material (hereinafter abbreviated as liner material) of the present invention will be described.
FIG. 1 shows a liner material according to this embodiment. The liner material 10 is provided with a first layer 11 made of a thermoplastic resin composition and a second layer 12 made of polyester adjacent to each other.

In the liner material 10, examples of the thermoplastic resin composition forming the first layer 11 include a mixture of a polyolefin resin and an elastomer, an ethylene-vinyl acetate copolymer, and the like.
Examples of elastomers include styrene / ethylene / butylene / styrene copolymers (SEBS), styrene / ethylene / propylene / styrene copolymers (SEPS), ethylene / propylene copolymers, and ethylene / propylene / conjugated diene copolymers. (EPDM). Since such a polyethylene-containing elastomer has high elasticity, the adhesion to the bottle can can be increased.
Examples of the polyolefin resin include low density polyethylene, linear low density polyethylene, ultra-low density polyethylene, and polypropylene.
The vinyl acetate content of the ethylene-vinyl acetate copolymer is preferably 5 to 30% by mass.
Furthermore, the thermoplastic resin composition may contain liquid paraffin, titanium dioxide as a coloring pigment, a lubricant, a stabilizer, a dispersant, and the like.

  When a mixture of a polyolefin resin and an elastomer is used as the thermoplastic resin composition forming the first layer 11, the content of the polyolefin resin is 50 to 80% by mass and the content of the elastomer is 10 to 30% by mass. It is preferable. If the total of the polyolefin resin and the elastomer is 60% by mass or more in the thermoplastic resin composition, the elasticity of the liner material can be sufficiently ensured, so that the bottle can can be more closely adhered to the liner material.

  In order to produce the thermoplastic resin composition forming the first layer 11, polyethylene and an elastomer, or an ethylene-vinyl acetate copolymer, and if necessary, other additives are blended, and these are melt mixed. To do. In the melt mixing, for example, a kneader, a Banbury mixer, a roll, a single screw or a twin screw extruder is used, and the temperature condition in the melt mixing is, for example, about 190 to 240 ° C.

The polyester constituting the second layer 12 has a crystallinity of 20 to 60% by mass, preferably 30 to 50% by mass. When the degree of crystallinity of the polyester is 20% by mass or more, the unplugging property is increased, and the beverage is prevented from being altered in order to suppress the absorption of the components of the beverage, for example, the deterioration of the flavor property is prevented. Moreover, impact resistance is made high because crystallinity is 60 mass% or less. That is, when the degree of crystallinity is 20 to 60% by mass, the quality of the beverage is prevented and the opening and impact resistance are excellent. Furthermore, if the crystallinity is 30 to 50% by mass, the effect becomes remarkable. In addition, when the crystallinity exceeds 60% by mass, the second layer 12 becomes hard, the followability of the seal portion tends to decrease, and the impact resistance tends to decrease. Is within the above range, there is no particular limitation, and examples include polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), polybutylene naphthalate (PBN), and the like. Among these, polyethylene terephthalate is preferable because it is inexpensive and excellent in physical properties.

In the liner material 10, it is preferable that a lubricant is attached to the surface of the second layer 12. If the lubricant adheres to the surface of the second layer 12, the friction becomes smaller, so the opening torque becomes smaller and the opening performance becomes higher. Examples of the lubricant include fatty acid, fatty acid amide, and ethylene bis fatty acid amide.
Furthermore, as fatty acids, caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, margaric acid, stearic acid, arachidic acid, behenic acid, n-tridecylenic acid, n-pentadecylenic acid, decenoic acid, oleic acid, erucine C8 to C22 saturated or unsaturated fatty acids such as acids, linoleic acid, linolenic acid, arachidonic acid, eicosapentanoic acid can be used.
Examples of fatty acid amides include caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, margaric acid, stearic acid, arachidic acid, behenic acid, n-tridecylene acid, n-pentadecylenic acid, decenoic acid, oleic acid, erucic acid Amide compounds of C8 to C22 saturated or unsaturated fatty acids such as linoleic acid, linolenic acid, arachidonic acid, eicosapentanoic acid, etc. can be used.
As the ethylene bis-fatty acid amide, an ethylene bis-amide compound of a C16 to C18 saturated or unsaturated fatty acid such as palmitic acid, margaric acid, stearic acid, oleic acid or the like can be used.

  Although there is no restriction | limiting in particular as a method of manufacturing this liner material 10, For example, the polyester film with a crystallinity of 20-60 mass% is bonded to the sheet | seat which consists of a thermoplastic resin composition containing polyethylene and an elastomer. And a method of cutting the laminate into a circular shape. Further, a sheet made of the thermoplastic resin composition may be cut into a circular shape, and then a polyester film corresponding to the shape may be bonded. However, cutting after bonding the polyester film is suitable for mass production. When a polyester film is bonded to a sheet made of a thermoplastic resin, an adhesive may be interposed.

  In the liner material 10 described above, a second layer 12 made of polyester is provided adjacent to a first layer 11 containing a thermoplastic resin composition. It is possible to prevent the beverage from coming into contact with the first layer 11. Therefore, it becomes difficult for some of the components of the beverage to be absorbed and adsorbed onto polyethylene or elastomer, so that the beverage can be prevented from being altered. In addition, since the polyester forming the second layer 12 has a specific crystallinity, it is possible to prevent the beverage from being deteriorated because the absorption of the beverage components is suppressed, and the opening torque is reduced. Excellent. Moreover, since it is excellent in impact resistance, it is hard to be damaged even if it receives an impact.

Next, an embodiment of the cap will be described.
FIG. 2 shows a cap according to this embodiment. The cap 1 is of a type that is rotated and opened, and includes a circular top plate portion 20, a peripheral wall portion 30 that substantially hangs down from the periphery of the top plate portion 20, and an inner surface 21 of the top plate portion 20. And a disc-shaped liner material 10 provided on substantially the entire surface of the aluminum alloy cap. In addition, a score line 31 is formed on the peripheral wall portion 30 of the cap 1 to facilitate cutting.

In the cap 1, the first layer 11 of the liner material 10 is in contact with the inner surface 21 of the top plate portion 20 of the cap 1, and the second layer 12 is disposed on the side in contact with the beverage.
Examples of the method of providing the liner material 10 on the inner surface 21 of the cap top plate portion include a method in which the first layer of the liner material is heated and heat-sealed while being in contact with the inner surface of the top plate portion of the cap. It is done. Moreover, you may provide a liner material in a cap through an adhesive agent.

As a method of attaching the cap to the bottle, for example, as shown in FIG. 3, the cap 2 in which the threaded portion is not formed on the peripheral wall portion 30, and the cap of the bottle can 50 filled with beverage as shown in FIG. 4. Cover the portion 51 and capping the cap in this state. By the capping process, a screw portion 32 (female screw portion) is formed on the peripheral wall portion 30 of the cap 1 along the male screw lead 52 of the cap portion 51 of the bottle can 50, and the lower portion 33 of the peripheral wall portion 30 is expanded on the bottle can 50. It is wound around the protruding portion 53 to form a final cap shape. Thus, the cap 1 is attached to the base 53 by being tightened. At this time, the inside of the bottle can is sealed by pressing the liner material 10 provided on the inner surface 21 of the cap top plate 21 to the end of the base 51.
The bottle can sealed with this cap may be made of aluminum alloy, glass, plastic, or metal other than aluminum alloy.

When opening the cap attached to the bottle can, the cap 1 is rotated counterclockwise. Due to the rotation, the cap 1 tends to move away from the bottle can 50, but the lower portion 33 of the peripheral wall portion 30 of the cap 1 is wound around and fixed to the bulging portion 53 of the bottle can 50. Therefore, by continuing the rotation, the cap 1 is separated at the score line 31, and the portions other than the lower portion 33 of the peripheral wall portion 30 of the separated cap 1 are moved upward and opened.
The cap that has been opened can be re-sealed by screwing again into the mouthpiece of the bottle can. Even in this case, the inside of the bottle can can be sealed because the end of the base is pressed against the liner material.

  In the cap described above, a liner material is provided on the inner surface of the top plate so that the second layer made of polyester is in contact with the beverage, and the beverage may contact the first layer containing polyethylene or elastomer. It is prevented. Therefore, it is difficult to denature the beverage inside the bottle can, and for example, it is possible to prevent a decrease in flavor properties. Further, since the polyester forming the second layer of the liner material has a specific crystallinity, the opening torque can be reduced, the opening performance is excellent, and the quality of the beverage is suppressed.

The cap provided with the liner material can be applied to any beverage, but is particularly suitable for beverages containing emulsion, such as sports beverages. This is because beverages containing emulsions are particularly easily absorbed and modified by polyolefins and elastomers, but if this liner material is used, it is difficult for even beverages containing emulsions to be altered.
In the above-described embodiment, the liner material is a layer in which the first layer made of the thermoplastic resin composition and the second layer made of polyester are provided adjacent to each other. As long as is in contact with the beverage, a multilayer structure having layers other than these layers may be used.

(Experimental example 1)
A thermoplastic resin composition is prepared by mixing 65% by mass of polyethylene, 25% by mass of styrene / ethylene / butylene / styrene copolymer (SEBS) and 10% by mass of liquid paraffin, and the thickness of the thermoplastic resin composition is increased. A 1.0 mm sheet was formed. Then, a polyethylene terephthalate film (second layer) having a crystallinity of 0 mass% and a thickness of 20 μm was bonded to this sheet (first layer) through an adhesive to obtain a laminate.
Next, this laminate was cut with an annular cutter having a diameter of 37 mm to obtain a cap liner material. Then, after arrange | positioning a liner material on the top-plate part inner surface of an aluminum-made cap so that a 1st layer might contact the cap top-plate part inner surface, it heat-seal | fused. Next, the cap was capped into an aluminum bottle can having a diameter of 38 mm and a volume of 310 ml filled with a pseudo beverage containing an emulsion to obtain a final cap.

And the flavor property, opening property, and impact resistance were evaluated as follows. The evaluation results are shown in Table 1.
<Flavour>
The bottle filled with the emulsion pseudo beverage was left to stand for 1 month by inversion, and then the absorption of the content on the liner material was evaluated by measuring the absorption rate of the content at 660 nm with a spectrophotometer. The initial absorption rate of the simulated liquid was 0.240.
<Openability>
The bottle filled with the emulsion pseudo beverage was left to stand at room temperature for 24 hours, and the torque required for the cap to start rotating first was measured with an opening torque measuring device.
<Impact resistance (drop test)>
Using a bottle can with a cap filled with contents, with the cap of the bottle can with the cap facing downward, the can axis is tilted about 10 ° with respect to the vertical direction, and the height is set on a flat plate made of iron or the like. When the contents were naturally dropped from a position of about 30 cm, the contents were visually checked for leakage. The determination is as follows.
When liquid or gas leaks out of 10 cans
When 3-7 cans out of 10 cans, liquid or gas leaks ... △
When 2 or less of 10 cans, liquid or gas leaks ...

(Experimental Examples 2-8)
A cap was obtained in the same manner as in Experimental Example 1 except that the crystallinity of the polyester was changed in the range of 10 to 70% by mass. Also about these, flavor property, opening property, and impact resistance were evaluated, and the evaluation results are shown in Table 1.

In Experimental Examples 3 to 7 in which the degree of crystallinity of the polyester is in the range of 20 to 60% by mass, the absorption of the pseudo beverage component is suppressed and the deterioration of the flavor property is prevented. The property was excellent. In particular, it was excellent in Experimental Examples 4 to 6 in which the crystallinity was in the range of 30 to 50% by mass.
On the other hand, in Experimental Examples 1 and 2 in which the degree of crystallinity of the polyester is less than 10% by mass, the flavor property is low, and in Experimental Example 1, the opening property is also inferior. Moreover, in Experimental Example 8 in which the crystallinity of the polyester exceeded 60% by mass, the impact resistance was low.

It is a partially broken side view showing a liner material for a cap according to an embodiment of the present invention. It is a partially broken side view showing the cap of the example of one embodiment concerning the present invention. It is a partially broken side view which shows the cap before attaching to a bottle can. It is a partially broken side view which shows the state at the time of attaching a cap to a bottle can. It is a partially broken side view which shows the conventional cap.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cap 10 Liner material 11 1st layer 12 2nd layer 20 Top plate part 21 Inner surface 30 Perimeter wall part

Claims (3)

In the liner material for the cap provided on the metal cap that is opened by rotating,
A liner material for a cap comprising a first layer made of a thermoplastic resin composition and a second layer made of polyester having a crystallinity of 20 to 60% by mass and in contact with a beverage.   The cap liner material according to claim 1, wherein a lubricant is attached to the surface of the second layer.   It has a top plate part, a peripheral wall part substantially hanging from the periphery of the top plate part, and a cap liner material according to claim 1 or 2, wherein the first layer is in contact with the inner surface of the top plate part. Characteristic cap.

Images