JP2012210962A - Lid material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lid material that is excellent in microwave oven aptitude, disposability, and dead holding properties, and further, is undetectable by a metal detector.SOLUTION: The lid material includes a laminated body having a paper layer, a first adhesive layer, a resin film layer, a second adhesive layer, and a sealant layer in this order. The paper layer is a layer formed of a processed paper formed by coating or impregnating one side or both sides of a base paper with wax, or a processed paper internally added with wax by paper-making after mixing a base paper material with wax. The laminated body does not have a layer made of aluminum.

Description

  The present invention relates to a lid material used for a cup-shaped packaging container, in particular, a laminate comprising paper as a base material and not including a layer made of aluminum as a constituent element, dead hold property, suitability for microwave oven and The present invention relates to a lid that is excellent in discardability and is not detected by a metal detector, and a package using the lid.

  When using a packaging body such as instant noodles, the lid material is partially opened, hot water is poured into the packaging body for hot water reconstitution, the lid material is returned and resealed. Accordingly, the lid used for the package has a curved shape so as not to block the opening at the time of opening, in addition to functions such as content protection required for a normal lid, and then reseals it. Sometimes plastic deformation and shape retention, that is, dead hold, are required to return to the smooth shape before opening and hold it.

  Conventionally, a laminated body including a layer made of a metal such as aluminum has been used as a lid material that satisfies these requirements (Patent Document 1).

  However, since a lid material including a layer made of a metal such as aluminum is detected by a metal detector, a metal detector for detecting a metal foreign object mixed in is applied to a package using the lid material. There was a problem that I could not. In addition, when a package using a lid containing a metal foil is cooked in a microwave oven, there is a problem that sparks can occur at the outer periphery of the metal foil. Further, the lid material is inferior in discardability, and when the used lid material is incinerated, there is a problem that a metal such as aluminum adheres to the incinerator and shortens the life of the incinerator.

JP 2001-287317 A

  The present invention solves the above-mentioned problems and does not have a layer made of a metal such as aluminum in the layer structure, so that it is excellent in suitability for a microwave oven, that is, applicable to cooking in a microwave oven, and suitable for disposal. An object of the present invention is to provide a lid material that is excellent, that is, does not emit metal waste during incineration, is not detected by a metal detector, and has an excellent dead hold property, and a package using the lid material. .

  As a result of various studies, the present inventors have at least a lid made of a laminate having a paper layer, a first adhesive layer, a resin film layer, a second adhesive layer, and a sealant layer in this order. The paper layer is a processed paper obtained by coating or impregnating a wax on one or both sides of the base paper, or a process in which wax is internally added by mixing the raw material of the base paper with the wax and then making the paper. It was found that a cover material, which is a layer made of paper, and the laminate does not have a layer made of aluminum, achieves the above-mentioned object.

The present invention is characterized by the following points.
1. A cover material comprising a laminate having at least a paper layer, a first adhesive layer, a resin film layer, a second adhesive layer, and a sealant layer in this order, wherein the paper layer comprises one side of a base paper or A laminate comprising a processed paper coated or impregnated with wax on both sides, or a processed paper in which wax is internally added by mixing the raw material of the base paper and the wax, and then papermaking. Does not have a layer made of aluminum.
2. 2. The wax according to 1 above, wherein the wax is selected from the group consisting of paraffin wax, microcrystalline wax, a copolymer of a styrene monomer and another vinyl monomer, a silicone resin, and a mixture thereof. Cover material.
3. 3. The lid material according to 1 or 2 above, wherein the wax is coated or impregnated in an amount of 5 to 100 g per 1 m ^{2 of} processed paper, or added internally.

  When the lid of the present invention is partially opened and bent, for example, when pouring hot water into a container, the curved open can be maintained, and the lid can be returned to its original smooth state. When it is resealed, the smooth resealed state can be maintained, that is, excellent dead hold property is exhibited.

  In addition, the laminate constituting the lid material of the present invention does not have a metal foil such as an aluminum foil in the layer structure, so that it is excellent in suitability for microwave ovens and disposal, and can be applied for contamination inspection by a metal detector. It is.

It is a schematic sectional drawing which shows the example about the layer structure of the laminated body which comprises the cover material of this invention.

The present invention will be described in detail below.
<1> Layer Configuration of Laminate Constructing Cover Material of the Present Invention FIG. 1 is a schematic cross-sectional view showing an example of a layer configuration of a laminate used in the present invention.
In the present invention, as shown in FIG. 1, the laminate includes a paper layer (1), a first adhesive layer (2), a resin film layer (3), a second adhesive layer (4), and a sealant. The five layers (5) have a basic layer structure, and the paper layer (1) is a processed paper obtained by coating or impregnating wax on one side or both sides of the base paper, or a raw material for the base paper. It is a layer comprising a processed paper in which wax is added internally by mixing with wax and then making paper.

In addition, if necessary, a printing layer may be provided on the surface of the paper layer that is not adjacent to the first adhesive layer, and an optional surface protective layer such as a polypropylene film may be provided.
Further, between the first adhesive layer (2) and the resin film layer (3) or between the resin film layer (3) and the second adhesive layer (4), a layer bearing a light shielding property, or a polyethylene resin A cushion layer that reinforces the close contact between the lid and the container may be provided.

  Hereinafter, the resin names used in the present invention are those commonly used in the industry.

<2> Paper Layer The paper layer constituting the lid material of the present invention is a processed paper obtained by coating or impregnating wax on one side or both sides of the base paper, or after mixing the raw material of the base paper and the wax. This is a layer composed of a processed paper in which wax is internally added by papermaking.

The base paper constituting the paper layer is a paper that provides a base material on which a wax is applied or impregnated and gives rigidity to the lid. Arbitrary paper can be used depending on the desired rigidity and the impregnation property of the wax to be used, for example, high-quality paper, imitation paper, art paper, coated paper, pure white roll paper, special kraft paper, bleached kraft paper In addition to the above, label paper having improved water resistance, cup base paper, and the like can be used. The thickness of the paper used is in the range of 50 to 200 g / m ² , more preferably 70 to 120 g / m ² in terms of rice basis weight. If the rice basis weight is less than 50 g / m ² , the thickness is too thin and the lid material is insufficient in rigidity, and good dead hold properties cannot be obtained. On the other hand, when the basis weight of the rice exceeds 200 g / m ² , the rigidity of the lid material becomes too high, and the preferable curled curl shape of the lid material at the time of opening can be hindered.

  The wax coated or impregnated on the base paper or mixed with the raw material of the base paper may be any wax that is solid at room temperature (23 ° C.) and becomes a low viscosity liquid by heating. For example, plant wax such as carnauba wax, animal wax such as beeswax, mineral wax such as montan wax, petroleum wax such as paraffin wax and microcrystalline wax, silicone resin, styrene monomer and other vinyl monomers Synthetic waxes such as copolymers thereof, and various modified waxes that are derivatives thereof, for example, blended waxes blended with synthetic resins having good compatibility such as oxidized wax and polyethylene. These waxes may be used alone or in combination of two or more. Particularly preferred are waxes selected from the group consisting of paraffin wax, microcrystalline wax, copolymers of styrene monomers and other vinyl monomers, silicone resins, and mixtures thereof. These waxes exhibit viscoelasticity suitable for the development of dead-holding properties when coated, impregnated or internally added to the base paper.

  As the silicone resin in the present invention, any generally known solid resin at normal temperature can be used according to the use of the lid material or the properties of the paper to be used. For example, alkylmethylpolysiloxane , Alkyl dimethicone wax, stearoxy dimethicone, behenoxy dimethicone, stearyl dimethicone, cetearyl dimethicone, cetyl dimethicone, and mixtures thereof, but are not limited thereto.

  Moreover, as a copolymer of a styrene monomer and another vinyl monomer, a styrene-acrylic acid copolymer, a styrene-maleic acid copolymer, a styrene-acrylic acid-acrylate ester copolymer, Styrene-maleic acid-maleic acid ester copolymer and the like are exemplified, but not limited thereto.

If necessary, the above wax may further include a plasticizer, a stabilizer, an antioxidant, an ultraviolet absorber, an antistatic agent, a dye, a pigment, a colorant, an inorganic filler, a flame retardant, a lubricant, a reinforcing material, a processing aid, One or more optional additives selected from the group consisting of a slip agent, an anti-sticking agent and a release agent may be included in an amount that does not affect the dead hold property.
Examples of the wax suitably used in the present invention include paraffin wax-115 manufactured by Nippon Seiwa Co., Ltd.

  When the paper layer of the present invention comprises a processed paper obtained by coating or impregnating wax on one or both sides of the base paper, its production is suitable for coating by heating and melting on one or both sides of the base paper. It is carried out by applying or impregnating a wax having a viscosity liquid once or a plurality of times by any coating or impregnation means. After coating and impregnation, aging in a thermostatic bath may be performed in order to prevent the occurrence of distortion due to shrinkage during solidification of the wax.

  The wax may be coated or impregnated on the surface of the base paper in the form of a wax emulsion obtained by emulsifying molten wax and water. Further, a wax emulsion may be sprayed or impregnated on a wet base paper in the middle of the paper manufacturing process. In any of these cases, a further drying step is required. By using the wax in the state of a wax emulsion, the coating / impregnation operation is facilitated, and a smooth and beautiful coating film is easily obtained.

The total coating amount of the wax is 5 to 100 g, preferably 10 to 30 g, per 1 m ^{2 of} paper. If the coating amount is less than 5 g / m ² , the paper cannot be prevented from returning to its original state, and sufficient dead hold property cannot be obtained. On the other hand, when it is more than 100 g / m ² , production and processing become difficult, and the cost increases, which is not preferable.

  Examples of the coating / impregnation means include, but are not limited to, roll coating using a size press roll coater, gravure roll coater, etc., spray coating, dipping, and coating with a brush.

  In another embodiment, when the paper layer is made of a processed paper in which the wax is internally added by mixing the raw material of the base paper and the wax and then making the paper, the production is performed by mixing the pulp raw material with the molten wax. The paper can be made by any internal paper making method.

The added amount of the wax is an amount in which 5 to 100 g, preferably 10 to 30 g, of wax is internally added per 1 m ^{2 of} the processed paper. If the amount of wax added is less than 5 g / m ^2, it is not possible to prevent the paper from returning to its original state, and sufficient dead hold property cannot be obtained. On the other hand, when it is more than 100 g / m ² , production and processing become difficult, and the cost increases, which is not preferable.

The thickness of the paper layer is 55 to 300 g / m ² , preferably 80 to 150 g / m ² . When it is thinner than 55 g / m ² , good dead hold property cannot be obtained. ^{On the other hand, if} it is thicker than 300 g / m ² , subsequent processing becomes difficult, which is not preferable.

<3> First Adhesive Layer In the laminate constituting the lid member of the present invention, the paper layer and the resin film layer are laminated via the first adhesive layer. Although this lamination can be performed by any method, it is preferably performed by a dry lamination method in order to increase the adhesive strength.

  As the dry laminating adhesive for forming the first adhesive layer, any dry laminating adhesive generally used for food packaging can be used. Specifically, polyurethane adhesives, acrylic adhesives, isocyanate adhesives, and the like can be used. Examples of the adhesive preferably used in the present invention include Takelac, Takenate manufactured by Mitsui Chemicals, Tomoflex manufactured by Toyo Morton Co., Ltd., Seika Bond manufactured by Dainichi Seika Kogyo Co., Ltd., and DIC Graphics Co., Ltd. ) Dick dry manufactured by Rock Dick, Rock Bond J manufactured by Rock Paint Co., Ltd., Adlock and the like.

  The adhesive for dry lamination can be applied by any coating means such as roll coating using a size press roll coater or gravure roll coater, spray coating, coating with a brush, or the like.

The thickness of the first adhesive layer is 0.5 to 10 g / m ² (when dried), more preferably 1 to 5 g / m ² (when dried). If it is thinner than this, sufficient adhesive strength cannot be obtained, and if it is too thick, there is a concern of residual solvent.

<4> Resin film layer The resin film layer which comprises the cover material of this invention is a layer which consists of a resin film laminated | stacked in order to give intensity | strength to a cover material or to provide various barrier properties.

  As a resin film, arbitrary functional films can be used according to the use of a lid material. Such films include stretched or unstretched polyethylene terephthalate (PET) film, polypropylene (PP) film, polyamide (PA) film, polyvinyl chloride (PVC) film, polyethylene (PE) film, polybutylene terephthalate ( PBT) film, polycarbonate (PC) film, polystyrene (PS) film, normal cellophane (PT), polyvinyl alcohol (PVA) film, ethylene-vinyl alcohol copolymer (EVOH) film, saponified ethylene-vinyl acetate copolymer The film which consists of, etc. are mentioned. In addition, in order to improve the water vapor barrier property and oxygen gas barrier property of the lid member, a vapor deposition film in which an inorganic oxide (silicon oxide, aluminum oxide, etc.) is provided on the above-described film surface by vapor deposition can also be used.

The resin film layer may be composed of a multilayer resin film in which two or more resin films are laminated by a laminating method such as dry lamination, sandwich lamination, or extrusion lamination.
The thickness of the resin film layer is 5 to 50 μm, more preferably 6 to 20 μm. When the resin film layer is too thick, the dead hold property of the laminate is impaired.

<5> Second Adhesive Layer In the laminate constituting the lid member of the present invention, the resin film layer and the sealant layer are laminated via the second adhesive layer. This lamination is performed by applying an anchor coating agent as a second adhesive layer on the bonding surface of the resin film layer and extrusion coating a resin forming a sealant layer thereon. Alternatively, it may be carried out by applying an adhesive for dry lamination as a second adhesive layer on one bonding surface, and then laminating the other bonding surface on the other and dry laminating. . As the coating means, any means such as roll coating using a size press roll coater, a gravure roll coater or the like, spray coating, or coating with a brush can be used.

  As the anchor coating agent for forming the second adhesive layer, any known anchor coating agent of polyethyleneimine, polybutadiene, organic titanium, or isocyanate can be used. Moreover, as an adhesive for dry laminate forming the second adhesive layer, a urethane-based adhesive can be suitably used.

The thickness of the second adhesive layer, when using an anchor coating agent, 0.001 to 0.5 g / m ² (dry), more preferably 0.01 to 0.3 g / m ² (dry And when using an adhesive for dry lamination, it is 0.5 to 10 g / m ² (when dried), more preferably 1.0 to 5.0 g / m ² (when dried). If it is thinner than this, sufficient adhesive strength cannot be obtained, and if it is too thick, an effect corresponding to the cost required cannot be obtained.

<6> Sealant layer In the laminate constituting the lid of the present invention, the sealant layer is a layer that forms the innermost layer when used as a lid.

  In the present invention, the sealant layer is, for example, a polyolefin resin such as linear low-density polyethylene (LLDPE), low-density polyethylene (LDPE), high-density polyethylene (HDPE), or unstretched polypropylene (CPP) excellent in heat sealability, or It is a layer made of an ethylene copolymer resin such as an ethylene-vinyl acetate copolymer (EVA), an ethylene-acrylic acid copolymer (EAA), or an ethylene-methacrylic acid copolymer (EMAA). In order to improve the low temperature sealing property and the easy peel property, these resins may be mixed with an incompatible resin such as polystyrene and polybutene in an arbitrary amount.

  The sealant layer is formed by subjecting the resin constituting the sealant layer to melt extrusion coating on the second adhesive layer made of the anchor coating agent coated on the bonding surface of the resin film layer. Is called. Or you may dry laminate with a resin film layer through the 2nd adhesive bond layer which consists of an adhesive agent for dry laminations using the sealant film which consists of resin which comprises said sealant layer.

  The thickness of the sealant layer is 10 to 100 μm, preferably 30 to 50 μm. If it is thinner than this, sufficient adhesive strength cannot be obtained, and if it is too thick, an effect corresponding to the cost required cannot be obtained.

<7> Lid The lid material of the present invention is a cup-shaped packaging container, particularly a food packaging container, especially a packaging container for sealing the contents of instant foods such as cup ramen and cup fried noodles, confectionery, jelly, etc. It can be suitably used as a lid material. Moreover, since it does not have the layer which consists of aluminum, it is applicable also to the packaging container of the instant food cooked using a microwave oven.

  In order to produce a package filled with the contents by applying the lid material of the present invention to a packaging container, the lid material of the present invention is applied to the opening of the packaging container having a thermoplastic resin layer as the outermost layer. It can be performed by superposing and heat-sealing so that the surface of the sealant layer is in contact.

  Next, the present invention will be specifically described with reference to examples.

[Example 1]
Amount of coating on one side of high-quality paper (made by Nippon Paper Industries Co., Ltd.) with a basis weight of 52.3 g / m ^{2 on one} side of heated and melted paraffin wax (paraffin wax-115 made by Nippon Seiwa Co., Ltd.) The coated paper was coated at 10 g / m ² and cooled to produce a processed paper.

Subsequently, on one side of the processed paper obtained, a two-component curable polyurethane adhesive (manufactured by Mitsui Chemicals, Inc., main agent: Takelac A969 / curing agent: Takenate A5, solid content 2.5 g / m ² ), And a PET film (manufactured by Toyobo Co., Ltd., thickness 12 μm) was dry laminated thereon.

Next, a polyethyleneimine-based anchor coating agent (Nippon Catalytic Epomin ^(R) P1000) was applied on the PET film surface of the obtained laminated film at a coating amount of 0.1 g / m ² (when dried). Then, a polyethylene resin (JMX Co., Ltd. SMX Y03) was coated by a melt extrusion coating method to provide a sealant layer, and a laminate constituting the lid of the present invention was produced.

The obtained laminate was punched into a circular shape with a diameter of 100 mm, and a knob piece was provided on a part of the outer periphery to obtain a lid material of the present invention. This was heat-sealed on a flange of a paper cup having a low-density polyethylene resin layer (thickness 20 μm) as the outermost layer with a ring sealer at 160 ° C. for 0.7 seconds at a pressure of 2.8 kgf / cm ² . The resulting package had good sealing properties. Further, when the knob piece was pulled at an angle of 135 ° with respect to the container flange to open the half of the lid, the lid material of the present invention retained the curved opening shape, and the opening point on the container flange (the position where the knob piece was located) ) To the position of 30 mm at a horizontal distance in the opening direction, the lid material and the container flange were not in contact. Further, when the lid member was returned to its original state and resealed, the lid member was held with the opening portion resealed in a smooth state. That is, the lid material of the present invention showed a good dead hold property.

[Example 2]
A lid material of the present invention and a package using the same were produced in the same manner as in Example 1 except that the amount of wax applied was 2.5 g / m ² per side. The resulting package had good sealing properties. Further, when the knob piece was pulled at an angle of 135 ° with respect to the container flange to open the half of the lid, the lid material of the present invention retained the curved opening shape, and the horizontal distance from the opening point to the position of 20 mm in the opening direction. The lid material and the container flange were not in contact. Furthermore, when the lid member was returned to its original state and resealed, the reseal smooth state was maintained and good dead hold property was exhibited.

[Example 3]
A lid material of the present invention and a package using the same were produced in the same manner as in Example 1 except that the amount of wax applied was 20 g / m ² per side. The resulting package had good sealing properties. Moreover, when the knob piece was pulled at an angle of 135 ° with respect to the container flange to open the half of the lid, the lid material of the present invention retained the curved opening shape, and the horizontal distance from the opening point to the position of 30 mm in the opening direction. The lid material and the container flange were not in contact. Furthermore, when the lid member was returned to its original state and resealed, the reseal smooth state was maintained and good dead hold property was exhibited.

[Example 4]
A lid material of the present invention and a package using the same were produced in the same manner as in Example 1 except that high-quality paper having a basis weight of 81.4 g / m ² (manufactured by Nippon Paper Industries Co., Ltd.) was used. The resulting package had good sealing properties. Moreover, when the knob piece was pulled at an angle of 135 ° with respect to the container flange to open the half of the lid, the lid material of the present invention retained the curved opening shape, and the horizontal distance from the opening point to the position of 30 mm in the opening direction. The lid material and the container flange were not in contact. Furthermore, when the lid member was returned to its original state and resealed, the reseal smooth state was maintained and good dead hold property was exhibited.

[Comparative Example 1]
The lid and the same were used in the same manner as in Example 1 except that any surface of high-quality paper (made by Nippon Paper Industries Co., Ltd.) having a basis weight of 52.3 g / m ² was not coated with wax. A package was produced. When the lid of the obtained package was half opened, the dead hold property did not appear, the lid material and the container flange contacted at the position of the opening point (0 mm), and the lid material closed the opening.

  Since the lid according to the present invention has the above-described characteristics, the lid is attached to an instant food cup container in which the lid is greatly opened and powder soup or ingredients need to be put into the container. It becomes possible to apply suitably. Moreover, since the layer which consists of aluminum is not provided, it becomes a cover material applicable also to the instant food cooked using a microwave oven.

1. Paper layer2. First adhesive layer3. Resin film layer 4. Second adhesive layer5. Sealant layer

Claims (3)

At least a lid made of a laminate having a paper layer, a first adhesive layer, a resin film layer, a second adhesive layer, and a sealant layer in this order,
The paper layer is a processed paper obtained by coating or impregnating a wax on one or both sides of the base paper, or a processed paper in which the wax is internally added by mixing the raw material of the base paper and the paper. A layer consisting of
The said laminated body does not have a layer which consists of aluminum, The said cover material characterized by the above-mentioned.   The wax according to claim 1, wherein the wax is selected from the group consisting of paraffin wax, microcrystalline wax, a copolymer of a styrene monomer and another vinyl monomer, a silicone resin, and a mixture thereof. The lid material described. 3. The lid according to claim 1, wherein the wax is coated or impregnated in an amount of 5 to 100 g per 1 m < ² > of processed paper, or is internally added.

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