JP2013193781A - Lid material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the strength of the start for opening, while keeping the barrier properties and sealability of a lid material, without increasing the number of processing steps, in an easily openable lid material.SOLUTION: A concave-convex pattern is provided on a surface opposite to a barrier layer of a heat seal layer. The concave-convex pattern is formed of the concave-convex pattern provided on the circumferential surface of a cooling roll, when the heat seal layer is film-formed. Further, the concave-convex pattern of the heat seal layer is provided at a place formed as a separation start position when a container is sealed with a lid material.

Description

  The present invention relates to a lid that seals a container filled with food or beverage, and particularly relates to a lid that is excellent in easy-openability.

  Generally, containers such as cups and trays used as containers for hermetically packaging foods and the like are hermetically sealed with a lid material having a heat sealable layer. The functions required for this lid material include hermetic sealing and easy opening, but an easy opening lid material that satisfies both of these functions has been developed and widely used.

  There are two main types of opening mechanisms for easy-open lids. The delamination type peels between the heat seal layer and the resin layer holding the heat seal layer, and the heat seal layer cohesively breaks. There is a cohesive failure type that peels.

  In the delamination type, delamination starts when the heat seal layer breaks and breaks down to the interlayer with the resin layer holding the heat seal layer, and then delaminates between the layers. On the other hand, in the cohesive failure type, cohesive failure starts with a failure from the surface of the sealant layer (heat seal layer) toward the inside of the sealant layer.

  In any type, since the peeling starts with the breakage of the sealant layer, the breaking strength of the sealant layer is related to the ease of peeling. As a method for reducing the breaking strength of the sealant layer, there is a case where the sealant layer is processed in advance to cause peeling, but an increase in the number of processing steps is a problem.

  For example, Patent Document 1 describes a lid material provided with a fine hole penetrating from a sealant layer side to a paper layer for the purpose of improving air permeability for gas sterilization in an easily openable lid material having a paper layer. .

JP 2009-7034 A

  However, in many food containers, a water vapor barrier property and an oxygen barrier are required, and from the viewpoint of hygiene and safety, a cover material that is completely penetrated until reaching the paper layer is often unsuitable.

  Moreover, there is a possibility that the number of processing steps is increased by performing the drilling process after stacking, and foreign substances generated during the drilling may be mixed into the food.

  Accordingly, an object of the present invention is to reduce the trigger strength of opening while maintaining the barrier property and sealing property of the lid material without increasing the processing steps of the easy-open lid material.

  In order to solve the above-mentioned problems, a lid material for sealing an opening of a container according to the present invention comprises a barrier layer and a heat seal layer, and has a concavo-convex pattern on the surface of the heat seal layer opposite to the barrier layer. It is characterized by providing.

  The uneven pattern is formed by an uneven pattern provided on the peripheral surface of the cooling roll when the heat seal layer is formed.

  Furthermore, the concave / convex pattern is partially provided in a portion of the heat seal layer that becomes a peeling start position when the lid member is sealed to the container.

  A method for producing a lid material used for sealing an opening of a container according to the present invention and comprising a barrier layer and a heat seal layer laminated on one side of the barrier layer is provided on one side of the barrier layer. When the heat seal layer is formed, an uneven pattern is formed on the surface of the heat seal layer opposite to the barrier layer by pressing the heat seal layer immediately after the film formation with a cooling roll having an uneven surface.

  The lid material according to the present invention has a structure in which a barrier layer is laminated on a base material layer, and a heat seal layer provided with an uneven pattern on the surface opposite to the barrier layer is laminated. The beverage can be prevented from deteriorating, and the opening strength can be lowered without increasing the number of processing steps, resulting in excellent ease of opening.

Schematic cross-sectional view showing the cross-sectional configuration of the lid according to the present invention Schematic cross-sectional view showing a state in which the lid according to the present invention is sealed in a container Schematic cross-sectional view showing the state of opening the lid according to the present invention

  Hereinafter, embodiments for carrying out the present invention will be specifically described with reference to the drawings. FIG. 1 is a schematic cross-sectional view showing a schematic cross-sectional configuration of a lid 1 according to the present invention. As shown in FIG. 1, the lid 1 is configured by laminating a base material layer 4, a barrier layer 3, and a heat seal layer 2 in this order. What is the adhesive surface of the heat seal layer 2 with the barrier layer 3? An uneven pattern 7 is provided on the opposite surface.

  The lid 1 is formed by laminating the base material layer 4 and the barrier layer 3 via the overcoat layer 5 and laminating the barrier layer 3 and the heat seal layer 2 via the adhesive layer 6. Yes. The method for laminating the base material layer 4, the barrier layer 3, and the heat seal layer 2 is not particularly limited as long as the base material layer 4, the barrier layer 3, and the heat seal layer 2 are laminated in this order.

The heat seal layer 2 is provided with frustum-shaped concave / convex patterns 7 having an average diameter of openings of several tens of μm to several hundreds of μm at a density of 1,000 / cm ^{2 to} 10,000 / cm ² . . In addition, the average diameter and density of the opening part of the uneven | corrugated pattern 7 will not be specifically limited if the sealing property and barrier property of the cover material 1 are maintained, and the trigger strength of opening can be lowered | hung. Further, in the lid 1, the depth of the uneven pattern 7 is set so as not to penetrate the heat seal layer 2. Since the depth of the uneven pattern 7 does not penetrate the heat seal layer 2, contact between the contents in the container and the adhesive of the adhesive layer 6 can be avoided.

  FIG. 2 is a schematic cross-sectional view showing a state in which the lid 1 according to the present invention is sealed in the container 8. The lid 1 is disposed so that the heat seal layer 2 is in contact with the seal portion of the container 8, and hermetically sealed by heating and pressurizing from the base material layer 4 side of the lid 1.

  FIG. 3 is a schematic cross-sectional view showing a state in which the lid 1 according to the present invention is opened. The seal part of the container 8 and the surface of the heat seal layer 2 of the lid member 1 are thermally welded, and the uneven pattern 7 becomes an opening trigger, and the peeling of the lid member 1 proceeds.

  It is desirable to use paper, polyethylene terephthalate (PET), nylon (Ny) or the like as the base material layer 4 in order to heat and pressurize and heat weld the surface of the heat seal layer 2 and the seal portion of the container 8.

  As the barrier layer 3, it is desirable to use polyethylene terephthalate (PET) or aluminum foil coated with a material having gas barrier properties. Moreover, when using aluminum foil, the barrier layer 3 and the base material layer 4 can be used by coating the surface opposite to the adhesive surface with the heat seal layer 2 according to the purpose of the container. It is also possible to omit the base material layer 4 from the layer structure of the lid material 1.

  For the heat seal layer 2, it is preferable to use a material that enables the lid 1 to be peeled from the container 8 with a small force. For example, an easy peel film can be suitably used.

  The concavo-convex pattern 7 of the heat seal layer 2 is a process of forming a film while laminating the heat seal layer 2 on the barrier layer 3 and pressing a cooling roll having a concavo-convex pattern corresponding to the concavo-convex pattern 7 on the surface as a plate. It can be formed by hitting. More preferably, the uneven pattern 7 is formed so as not to reach the surface opposite to the surface of the heat seal layer 2 to be sealed, that is, not to penetrate the heat seal layer 2. This is because by forming the uneven pattern 7 so as not to penetrate the heat seal layer 2, it is possible to prevent the overcoat agent used during film formation from passing through the uneven pattern 7 of the heat seal layer 2. It can be suitably used regardless of the type of agent. In the above description, the concave / convex pattern 7 is provided on the entire surface of the heat seal layer 2 to be sealed. However, if the trigger strength of opening can be reduced, the lid material 1 of the heat seal layer 2 is used as the container. The concave / convex pattern 7 may be partially provided at a position which becomes a peeling start position when the sealing is performed.

  Hereinafter, more specific examples of the lid according to the present invention will be described.

As a substrate layer and a barrier layer, an aluminum foil having a thickness of 50 μm was used, and an undercoat agent and an overcoat agent usable in a food container were applied to the surface opposite to the undercoat layer. The heat seal layer was formed using a resin having an easy peel property of a polymer blend of polyethylene and polypropylene. The unevenness pattern was formed on the surface of the heat seal layer without increasing the number of steps by pressing the cooling roll having the unevenness pattern shallower than 30 μm on the surface at the time of film formation by setting the thickness of the heat seal layer to 30 μm. As the specifications of the concavo-convex pattern, the average diameter of the openings was several μm to several tens of μm, the average depth was 25 μm, and the density was 1,000 to 2,000 / cm ² . In addition, the cover material which concerns on a present Example formed the heat-seal layer on the aluminum foil by coextrusion through the undercoat agent (Seikadyne 2701A by Dainichi Seika Co., Ltd., application amount 2-3g / m < ² >).

  The lid material processed in this way was cut one size larger than the seal part of the container (material: polypropylene resin) and thermally welded to the seal part. When the end of the lid member was pinched and pulled up as usual, the uneven pattern on the surface of the heat seal layer triggered the opening, and it was easy to open.

  The lid | cover material which concerns on this invention is useful for the lid | cover material etc. which are excellent in easy openability and seal the container filled with foodstuffs and drinks.

DESCRIPTION OF SYMBOLS 1 Cover material 2 Heat seal layer 3 Barrier layer 4 Base material layer 5 Adhesive layer 6 Undercoat layer 7 Concavity and convexity pattern 8 Container

Claims (4)

A lid that seals the opening of the container,
A barrier layer;
With a heat seal layer,
A lid material, wherein an uneven pattern that does not penetrate the heat seal layer is provided on a surface of the heat seal layer opposite to the barrier layer.   The lid material according to claim 1, wherein the concavo-convex pattern is formed by a concavo-convex pattern provided on a peripheral surface of a cooling roll when forming the heat seal layer.   The said uneven | corrugated pattern is partially provided in the location used as a peeling start position when the said cover material is sealed to the said container among the said heat seal layers, The lid | cover of Claim 1 or 2 characterized by the above-mentioned. Wood. A method for producing a lid material used for sealing an opening of a container, comprising a barrier layer and a heat seal layer laminated on one side of the barrier layer,
When forming the heat seal layer on the one surface side of the barrier layer, by pressing the heat seal layer immediately after film formation with a cooling roll having irregularities on the peripheral surface, the barrier layer of the heat seal layer and Is a method for producing a lid material, wherein an uneven pattern that does not penetrate the heat seal layer is formed on the opposite surface.

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