JP2008080769A - Lid material of cup for beverage - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inexpensive lid material for beverages having excellent piercing openability. <P>SOLUTION: The lid material 1 comprises a stretched plastic film 2, an aluminum foil 3, and a heat sealant layer laminated in this order from the outer face side to the inner face side. The heat sealant layer is a non-stretched polypropylene film 4 composed of a polypropylene homopolymer. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a lid member for sealing a mouth of a beverage cup filled with a beverage, and more particularly to a lid member for a beverage cup opened by piercing with a straw or the like.

  Beverages such as juice, coffee and milk drinks are often sold in plastic cups. In this case, a sheet-like lid material is bonded to the cup mouth by heat sealing, and the cup mouth is sealed by the lid material. When drinking the contents, it is generally opened by piercing the lid with a straw or the like. Therefore, the lid member is required to have a property that an opening can be easily formed by piercing with a straw or the like, that is, so-called piercing opening.

  As the lid material, for example, as disclosed in Patent Document 1, a sheet-like material in which a stretched plastic film, an aluminum foil, and a heat sealant layer are laminated in order from the outer surface side to the inner surface side is used. For the heat sealant layer, an unstretched polypropylene film made of, for example, an ethylene / propylene random polymer or an ethylene / propylene block copolymer is used. It is difficult to reach the opening because it stretches even when it is pierced. Therefore, with such a cover material, there is anxiety about the piercing opening property.

Therefore, for example, as disclosed in Patent Document 2, an unstretched polypropylene film that is a heat sealant layer and an aluminum foil are bonded to each other using an adhesive resin made of powdered modified polypropylene, and the temperature near the melting point of polypropylene. The cover material which heat-processed by is proposed. By the heat treatment, the elongation of the unstretched polypropylene is suppressed, and as a result, the piercing opening property of the lid member can be expected.
JP-A-9-323377 JP 2005-255173 A

  However, in the above-described conventional lid material, in order to suppress the elongation of unstretched polypropylene, which is a heat sealant layer, heat treatment under special conditions must be applied, which complicates the manufacturing process accordingly. As a result, the cost increases.

  Then, this invention is made | formed in view of said problem, and it aims at providing the lid | cover material of the cup for drinks which was cheap and stabbed and excellent in opening property.

  In order to achieve the above object, a lid for a beverage cup according to the present invention is a lid for sealing the mouth of a beverage cup, in which a stretched plastic film, an aluminum foil and a heat sealant layer are laminated in order from the outer surface side to the inner surface side. The heat sealant layer is an unstretched polypropylene film made of a polypropylene homopolymer. In the lid material having such a configuration, the heat seal layer is an unstretched polypropylene film made of a polypropylene homopolymer, so that it does not easily stretch when pierced with a straw or the like, and the piercing opening property is good. Moreover, no extra heat treatment under special conditions as in the prior art is required, and the lid material can be manufactured at low cost.

  Here, it is preferable that the unstretched polypropylene film has a thickness of 30 μm or less in view of sufficient piercing opening.

  In practice, the stretched plastic film is preferably a biaxially stretched polyethylene terephthalate film.

  Here, it is preferable that the thickness of the biaxially stretched polyethylene terephthalate film is 12 μm or less so as not to disturb the piercing opening property.

  According to the lid material for a beverage cup of the present invention, an inexpensive and excellent piercing opening property can be obtained.

  Below, one Embodiment of the lid | cover material of the cup for drinks of this invention is explained in full detail, referring drawings. FIG. 1 is a cross-sectional view showing a laminated structure of a lid member for a beverage cup according to an embodiment of the present invention, and FIG. 2 is a perspective view showing an appearance when the lid member is attached to a beverage cup.

  As shown in FIG. 1, the lid material 1 is a sheet material having a laminated structure, and as shown in FIG. 2, the lid material 1 is adhered to the mouth of a plastic cup 10 filled with a beverage by heat sealing. The mouth of the cup 10 is sealed. When drinking the contents, the lid member 1 is pierced with a straw 15 or the like, thereby forming an opening in the lid member 1 and opening the lid.

  As shown in FIG. 1, the lid material 1 is mainly composed of a transparent stretched plastic film 2 that is a base material and an aluminum foil in order from the outer surface side toward the inner surface side (from top to bottom in FIG. 1). 3 and an unstretched polypropylene film 4 which is a heat sealant layer is laminated. A pattern layer 5 is laminated on the inner surface of the outermost stretched plastic film 2, and an aluminum foil 3 is bonded thereto via an adhesive resin layer 6. The aluminum foil 3 and the innermost unstretched polypropylene film 4 are bonded via an adhesive resin layer 7.

  Particularly in the present embodiment, the innermost unstretched polypropylene film 4 is made of a polypropylene homopolymer. The unstretched polypropylene film 4 made of this polypropylene homopolymer has a hard and brittle characteristic as compared with the unstretched polypropylene film made of a conventional ethylene / propylene random polymer or ethylene / propylene block copolymer. It becomes difficult to stretch during piercing. Therefore, the puncture opening is good.

  However, if the thickness of the unstretched polypropylene film 4 is increased, it cannot be denied that the piercing and opening properties are lowered. In consideration of sufficient piercing opening, the thickness is preferably 30 μm or less, more preferably 25 μm or less. In addition, if the unstretched polypropylene film 4 is too thin, the necessary sealing properties are hindered in the first place. Therefore, the thickness is preferably 10 μm or more, more preferably 15 μm or more.

  In addition, as the unstretched polypropylene film 4 which consists of a polypropylene homopolymer, for example, Tosero SC (trade name) manufactured by Tosero Co., Ltd. No. Dazai FPK (trade name).

  As the stretched plastic film 2, stretched films of polyethylene terephthalate, polypropylene, polycarbonate, polystyrene, polyamide, polyvinyl chloride, saponified ethylene / vinyl acetate copolymer, cellulose acetate, and the like can be applied. Practically, a biaxially stretched polyethylene terephthalate film that has been stretched in the biaxial direction is preferred. However, the thickness when the biaxially stretched polyethylene terephthalate film is adopted as the stretched plastic film 2 is preferably 12 μm or less, and more preferably 9 μm or less so as not to hinder the puncture opening property. In addition, if the stretched plastic film 2 in that case is too thin, the protection of the pattern layer 5 and the aluminum foil 3 may be insufficient, and thus the thickness is preferably 6 μm or more.

  In such a lid material 1, since the innermost heat seal layer is the unstretched polypropylene film 4 made of polypropylene homopolymer, it is difficult to stretch when piercing with a straw 15 or the like, and the piercing opening property is good. is there. In addition, no extra heat treatment under special conditions as in the prior art is required, and the lid member 1 can be manufactured at low cost.

  In addition, the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, the pattern layer 5 may be laminated not on the inner surface of the outermost stretched plastic film 2 but on the outer surface and covered with a protective film.

  Subsequently, in order to determine the effectiveness of the lid member 1 described above, samples of Examples 1 to 3 below and samples of Comparative Examples 1 and 2 were prepared, and evaluation on puncture opening characteristics was performed.

<Example 1>
A 9 μm thick biaxially stretched polyethylene terephthalate film is laminated with an isocyanate adhesive on an aluminum foil with a thickness of 15 μm, and a polypropylene homopolymer type unstretched polypropylene with a thickness of 20 μm is placed on the surface of the aluminum foil via an isocyanate adhesive. A film (manufactured by Tosero Co., Ltd., trade name: Tosero SC) was laminated to prepare a sample of a lid.

<Example 2>
A lid sample was prepared in the same manner as in Example 1 except that a 25 μm thick polypropylene homopolymer type unstretched polypropylene film (trade name: Tosero SC, manufactured by Tosero Co., Ltd.) was used.

<Example 3>
A lid sample was prepared in the same manner as in Example 1 except that a polypropylene homopolymer type unstretched polypropylene film (trade name: Tosero SC, manufactured by Tosero Co., Ltd.) having a thickness of 30 μm was used.

<Comparative Example 1>
A 9 μm thick biaxially stretched polyethylene terephthalate film is laminated on an aluminum foil having a thickness of 15 μm with an isocyanate adhesive, and a 30 μm thick ethylene / propylene random copolymer type non-coated type is formed on the surface of the aluminum foil via an isocyanate adhesive. A stretched polypropylene film (manufactured by Toray Synthetic Film Co., Ltd., trade name: Treffan 3501) was laminated to prepare a sample of a lid material.

<Comparative example 2>
7 μm thick aluminum foil, 12 μm thick biaxially stretched polyethylene terephthalate film, 20 μm thick ethylene / propylene random copolymer type unstretched polypropylene film (trade name: Treffan 3501) A lid sample was prepared in the same manner as in Comparative Example 1 except that.

<Evaluation of piercing opening>
About the sample of the lid | cover material of said Examples 1-3 and Comparative Examples 1 and 2, the puncture strength was measured based on the test method prescribed | regulated to JIS_Z_1707. Here, there are three levels: “excellent” when the piercing strength is less than 5.5N (Newton), “good” when it is 5.5N to 6.5N, and “impossible” when it is 7.0N or more. It was evaluated with.

The results are summarized in Table 1 below.

  As is apparent from Table 1, the lid material samples of Examples 1 to 3 using unstretched polypropylene made of polypropylene homopolymer for the innermost heat sealant layer had low puncture strength and excellent puncture opening. On the other hand, the sample of the cover material of Comparative Examples 1 and 2 using unstretched polypropylene made of ethylene / propylene random copolymer for the heat sealant layer has high puncture strength and poor puncture opening. Here, in the sample of the lid material of Example 3, the heat sealant layer is thicker than the sample of the lid material of Examples 1 and 2, but at this thickness, the piercing opening is not so much. Does not get worse.

  INDUSTRIAL APPLICATION This invention is useful for the lid | cover material of the cup for drinks which seals the opening | mouth of the cup for drinks filled with the drink, and is opened by the stab with a straw.

It is sectional drawing which shows the laminated structure of the cover material which is one Embodiment of this invention. It is a perspective view which shows an external appearance when the cover material which is one Embodiment of this invention is mounted | worn with the cup for drinks.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cover material 2 Stretched plastic film 3 Aluminum foil 4 Unstretched polypropylene film which consists of polypropylene homopolymers 5 Picture layer 6 Adhesive resin layer 7 Adhesive resin layer 10 Cup 15 Straw

Claims (4)

In the lid that seals the mouth of the beverage cup,
In order from the outer surface side to the inner surface side, a stretched plastic film, an aluminum foil and a heat sealant layer are laminated,
A lid for a beverage cup, wherein the heat sealant layer is an unstretched polypropylene film made of a polypropylene homopolymer.   The lid material for a beverage cup according to claim 1, wherein the unstretched polypropylene film has a thickness of 30 µm or less.   The lid material for a beverage cup according to claim 1 or 2, wherein the stretched plastic film is a biaxially stretched polyethylene terephthalate film.   The lid for a beverage cup according to claim 3, wherein the biaxially stretched polyethylene terephthalate film has a thickness of 12 µm or less.

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