JP2008222273A - Paper-made lid - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a paper-made lid of a paper-made container which is free from any paper separation or the like of a paper-based material layer constituting a paper-made filter when opening the paper-made lid from the paper-made container, disposable as paper classification during the separate collection after the use, and satisfied with the Notice No. 52 of the Ministerial Ordinance by the Ministry of Health and Welfare dated December 27, 1952 "Ministerial Ordinance on the component standards of milk and dairy products" (hereinafter, abbreviated as "Ministerial Ordinance on Milk"). <P>SOLUTION: In a lid material capable of sealing a paper-made container and having the easy-to-open function, a thermoplastic resin intermediate layer, a flocculate-separation layer, and a heat-seal layer are successively layered on a paper base material layer, and a resin in which polybutene and low-density polyethylene are blended is used for the flocculate-separation resin. The blend ratio of polybutene to low-density polyethylene (polybutene/low-density polyethylene) is in a range of 2/8 to 8/2, and low-density polyethylene is used for the heat-seal layer. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a paper lid material for a paper container filled with yogurt, dairy products, fruit juice, jelly, etc. Specifically, there is no occurrence of paper smudges when opening, and paper classification at the time of separate collection after use As a paper lid material to be discarded.

  Conventionally, paper containers have been widely used mainly in the fields of dessert foods such as yogurt, pudding, jelly, and liquid drinks such as fruit juice, coffee, cocoa, and dairy drinks, or instant noodles and snack foods. And most of the lid materials used for paper containers are paper lid materials that are sealed by heat sealing in terms of storage stability and hygiene. Therefore, having an easy peel property is essential.

  Therefore, as one of the important functions of the paper lid material, there is sufficient sealing strength of the paper lid material to the paper container body, so that the paper lid material does not peel off from the paper container body at the product distribution stage. In addition, there is a demand for a balanced paper cover material that is not too weak and not too strong so that the paper cover material can be easily peeled off when used.

  Also, in paper containers, low-density polyethylene (hereinafter referred to as LDPE) is widely used as the heat seal layer on the inner surface, and the paper base material layer is usually used as the configuration of the paper lid material corresponding to the paper container. / Intermediate layer / heat seal layer. And in the intermediate layer, in order to prevent the paper base material layer from being peeled off during the opening of the portion sealed by heat sealing with the heat sealing layer on the inner surface of the paper container, the paper mess is not generated. Biaxially stretched films such as aluminum (hereinafter referred to as AL), polyethylene terephthalate (hereinafter referred to as PET), and nylon have been used.

For containers other than paper containers, for example, synthetic resin containers such as polystyrene, those having a configuration of a cohesive peeling type lid material are known (for example, see Patent Document 1).
JP-A-8-169441

  However, in the paper lid material configured as the paper base layer / intermediate layer / heat seal layer as described above, the heat seal layer of the paper lid material and the heat seal layer on the inner surface of the paper container are made of the same material. Since the resin is used, there is no easy opening at the time of opening, and many paper spots are generated due to peeling of the paper base material layer at the time of opening.

  In addition, since the material of the intermediate layer in the above configuration is expensive, the cost is high, and the paper and AL (or biaxially stretched film such as PET, nylon) at the time of separation and collection are different materials. Since AL generates a residue even when incinerated, it is by no means a preferable material, and an alternative material is desired in terms of recyclability.

In addition, when a paper container is used as a container whose contents are dairy products, etc., when the heat seal layer on the inner surface of the paper container for heat sealing the paper lid material is polyethylene, December 27, 1951 A seal strength of 13.3 kpa · 10 sec or more that satisfies the Ministry of Health and Welfare Ordinance No. 52 “Ministerial Ordinance on Component Standards of Milk and Dairy Products” (hereinafter referred to as “Milk Ordinance”) There was no problem. In addition, Appendix 4 of “Ministerial Ordinance on Milk”. Equipment and containers and packaging for milk, etc., standards for these raw materials and standards for manufacturing methods, (2) Containers and packaging for milk, etc., standards for these raw materials and standards for manufacturing methods, b Containers and packaging made of synthetic resin, and synthetic resin processed paper In container packaging
“As the sealing strength,
・ A hole with a diameter of 0 to 5 cm to 1.0 cm is made in the center of the side or bottom of a sealed container and package (if there is any content, remove it), and an air supply nozzle is installed. Then, connect the compressor and pressure gauge as shown in the figure.
-Next, when the compressor is operated and pressurization is performed up to 13.3 kpa in 10 seconds, there must be no damage to the packaging or air leakage. "
It is said.

  The present invention has been made in view of the above problems, and the object is a paper lid material for a paper container, and when opening a paper lid material from a paper container, There is no occurrence of paper smearing or the like in the paper base material layer constituting the paper lid material, and it can be discarded as a paper classification at the time of separate collection after use. Furthermore, the present invention provides a paper lid material that satisfies the “Ministry Ordinance for Milk”.

  In order to achieve the above object, a first aspect of the present invention is a lid material that seals a paper container and has an easy-opening function, wherein a paper base layer includes a thermoplastic resin intermediate layer, an agglomerated release layer, a heat seal. It is a paper lid material characterized by sequentially laminating layers.

  A second aspect of the invention is a paper lid material according to the first aspect of the invention, wherein a resin obtained by blending polybutene and low-density polyethylene is used for the cohesive release layer.

  According to a third aspect of the invention, in the invention of the second aspect, the blend ratio of polybutene and low density polyethylene (polybutene / low density polyethylene) is in the range of 2/8 to 8/2. It is a lid material.

  According to a fourth aspect of the present invention, there is provided a paper lid material according to the first to third aspects of the present invention, wherein a low density polyethylene is used for the heat seal layer.

  The invention of claim 5 is characterized in that, in the invention of claims 1 to 4, the thickness of the cohesive release layer is in the range of 3 to 30 μm, and the thickness of the heat seal layer is in the range of 3 to 20 μm. Paper lid material.

  The invention of claim 6 is a paper lid material according to the invention of claims 1 to 5, wherein the cohesive release layer and the heat seal layer are laminated by a co-extrusion laminating method.

  A seventh aspect of the invention is a paper lid material according to the first to sixth aspects of the invention, wherein the weight of the paper base layer is 51% or more of the total weight.

  The paper lid material of the invention of claim 1 has a structure in which a thermoplastic resin intermediate layer, a cohesive release layer, and a heat seal layer are sequentially laminated on a paper base material layer, and the paper lid material is opened from the paper container. At this time, since the paper lid material is peeled off by the cohesive peeling of the cohesive peeling layer, the paper lid material can be easily peeled and opened when used, and after opening, the flange portion of the paper container This has the effect that the paper lid material is not unsightly due to paper smudges and the like, and there is no food contamination.

  In addition, in the paper lid material of the invention of claim 2, by using a resin blended with polybutene and low-density polyethylene for the cohesive release layer, in addition to the effect of claim 1, it is easier to make the paper lid material. Can be peeled off and opened.

  In the paper lid material of the invention of claim 3, the blend ratio of polybutene and low-density polyethylene (polybutene / low-density polyethylene) is in the range of 2/8 to 8/2. In addition to the effect, the paper lid material can be peeled off and opened more easily, and at the same time, there is no generation of sealing due to heat at the time of heat sealing. Has the effect of

  Further, in the paper lid material of the invention of claim 4, by using low density polyethylene for the heat seal layer, in addition to the effects of claims 1 to 3, the milk specified in the “Ministerial Ordinance for Milk” It can be adapted to the use restrictions of containers, etc., and has the effect that there is no need for an exception application.

  In the paper lid material of the invention of claim 5, the thickness of the cohesive release layer is in the range of 3 to 30 μm and the thickness of the heat seal layer is in the range of 3 to 20 μm. In addition to the above effects, the heat seal layer does not tear when heat-sealed, resulting in poor adhesion, and the heat seal layer does not cut when opened, leaving a thin heat seal layer on the paper container. There is no problem.

  In addition, in the paper lid material of the invention of claim 6, the cohesive peeling layer and the heat seal layer are laminated by coextrusion laminating method, so that the cohesive peeling is the minimum necessary in addition to the effects of claims 1-5. Therefore, the thickness can be made practical and economical.

  The paper lid material of the invention of claim 7 is a paper lid material mainly composed of a paper base material layer, and the paper base material layer is configured to be 51% or more of the total weight. In addition to the effects of 6, when the paper container and the paper lid material of the present invention are combined, it is not necessary to separate and discard the paper container and the lid material at the time of separating and collecting the lid material of the paper container. It has the effect that it can be discarded as, and it is excellent in discardability.

  Further, when the paper lid material of the present invention is used in a paper container for storing dairy products, etc., the sealing strength that satisfies “Milk Ministerial Ordinance” can be 13.3 kpa · 10 sec or more. Have.

  As shown in FIG. 1, the paper lid material of the present invention has a structure in which a paper base layer 11, a thermoplastic resin intermediate layer 12, an agglomerated release layer 13, and a heat seal layer 14 are sequentially laminated. As shown in FIG. 2, the paper container 20 is sealed by heat-sealing the heat seal layer on the inner surface of the paper container 20 and the heat seal layer 14 of the paper lid material 10 of the present invention at the flange portion 21 of the paper container 20. Can be sealed. When the paper lid material 10 is peeled off from the paper container 20 and opened, as shown in FIG. 2B, the paper lid material is removed from the paper container 20 using the cohesive peeling of the cohesive peeling layer 13. 10 can be peeled off. In the configuration of the paper lid material 10 of the present invention, the heat seal layer 14 of the paper lid material 10 and the resin of the heat seal layer on the inner surface of the paper container 20 are made of the same kind of resin, and the stability of the sealing strength is given. Further, a predetermined seal is obtained by providing a cohesive release layer 13 between the paper base material layer 11 and the heat seal layer 14 of the paper lid material 10 and making the cohesive exfoliation layer within the cohesive peel layer 13. A feature is that the structure can obtain strength.

The paper base material layer 11 constituting the paper lid material 10 of the present invention is a main constituent material of the paper lid material 10 and is known (recycled) such as cup base paper, coat ball, milk carton base paper, corrugated cardboard, and micro flute. Paperboard (including paper) can be used. Moreover, as a soot amount of the paper base material layer 11 which comprises the paper lid | cover material 10 of this invention, the range of 100-500 g / m < ² > is preferable.

  Next, the thermoplastic resin intermediate layer 12 constituting the paper lid material 10 of the present invention is provided in order to protect the cushioning as the lid material, paper damage due to peeling when the paper base material layer 11 is opened, The resin used preferably has no heat sealability with the resin of the heat seal layer on the inner surface of the paper container 20, such as LDPE, MDPE (medium density polyethylene), HDPE (high density polyethylene), polypropylene, etc. Polyolefin resin, polyester resin, and polyamide resin can be used. When the resin of the thermoplastic resin intermediate layer 12 has a strong heat-sealing property with the resin of the heat seal layer on the inner surface of the paper container 20, when the lid material 10 is heat-sealed to the paper container 20, cohesive peeling When the layer 13 and the heat seal layer 14 are heated and melted, the cohesive release layer 13 and the heat seal layer 14 escape due to the seal pressure, and the thermoplastic resin intermediate layer 12 and the heat seal layer on the inner surface of the paper container 20 are thermally bonded. In some cases, the paper container 20 or the paper lid material 10 may be damaged.

  The thickness of the thermoplastic resin intermediate layer 12 constituting the paper lid material 10 of the present invention is preferably in the range of 10 to 30 μm. When the thickness of the thermoplastic resin intermediate layer 12 is less than 10 μm, the flow of the innermost agglomerated release layer 13 increases excessively due to the amount of heat and pressure at the time of heat sealing, and seal escape occurs to obtain a stable sealing strength. If the thickness exceeds 30 μm, the heat quantity, pressure conduction, and transmission loss during heat sealing increase, resulting in a waste of work.

  Next, the agglomerated release layer 13 constituting the paper lid material 10 of the present invention is a layer that agglomerates and peels at the inner layer when the paper lid material 10 sealed by heat sealing to the paper container 20 is opened. This is a layer made of a resin obtained by blending polybutene (hereinafter referred to as PB) and LDPE.

  And the blend ratio (PB / LDPE) of PB and LDPE is in the range of 2/8 to 8/2, and preferably in the range of 3/7 to 7/3. When the blend ratio of PB and LDPE is less than 2/8, the blended resin has a performance close to that of LDPE, and is strongly heat bonded to the heat seal layer on the inner surface of the paper container 20 and is not easily opened. When the blend ratio exceeds 8/2, the melt viscoelasticity due to PB increases, so that it becomes easy to generate a sealing fray due to heat during heat sealing. That is, an overseal is caused by resin escape and the opening is not stable.

  Since the paper container is formed by punching a predetermined blank in advance and then winding and fastening both ends thereof, when heat sealing the paper lid material and the flange portion of the paper container, both ends of the flange portion Since there is a step in the overlapped portion, seal unevenness is likely to occur due to this step, and this has caused paper smearing. Until now, the sealing strength at the time of peeling between the heat seal layer of the paper lid material and the heat seal layer on the inner surface of the paper container (usually the PE surface) tends to be weakened.

  When the cohesive release layer is the innermost surface, the peel strength (seal strength) between the cohesive peel layer of the paper lid material and the heat seal layer of the paper container is determined by the blend ratio of PB and LDPE of the cohesive peel layer However, if the LDPE is made rich, the sealing strength with the heat seal layer on the inner surface of the paper container will be stronger, but eventually the paper will be smeared, and the cohesive peel strength should be controlled by the blending ratio of PB and LDPE. Is actually impossible.

  Moreover, the thickness of the cohesive peeling layer 13 which comprises the paper lid | cover material 10 of this invention has the preferable range of 3-30 micrometers. When the thickness of the agglomerated release layer 13 is less than 3 μm, the flow of the innermost agglomerated exfoliation layer 13 increases excessively due to the amount of heat and pressure at the time of heat sealing, and a seal escape occurs to obtain a stable seal strength. If the thickness cannot be increased and the thickness exceeds 30 μm, the heat amount, pressure conduction, and transmission loss during heat sealing increase, resulting in a waste of work.

  Next, the heat seal layer 14 constituting the paper lid material 10 of the present invention is a layer that heat seals with the heat seal layer on the inner surface of the paper container 20, and the heat seal layer and heat seal on the inner surface of the paper container 20. Resins that can be used, usually polyethylene, ethylene / vinyl acetate copolymer, ethylene / acrylic acid copolymer, ethylene / acrylic acid ester copolymer, ionomer, saponified ethylene / vinyl acetate copolymer, polypropylene, polyester, etc. You can choose from. Moreover, when a paper container is used for dairy products, it is preferable to use a homopolymer of polyethylene, and among these, it is preferable to use LDPE. As described above, the reason for limiting the heat seal layer 14 to LDPE is that the use restriction of the milk container specified in the “Ministerial Ordinance on Milk” is taken into consideration. That is, if the cohesive release layer 13 is brought to the contact surface that directly contacts the contents, an exception application or the like is required.

  The thickness of the heat seal layer 14 constituting the paper lid material 10 of the present invention is preferably in the range of 3 to 20 μm. That is, it is preferable to form the paper lid material 10 as thin as possible so that the heat seal layer 14 is cut at the end when the paper lid material 10 is opened from the paper container 20. If the thickness is less than 3 μm, the heat seal layer 14 is broken when heat-sealing, resulting in poor adhesion, and if it exceeds 20 μm, the heat-seal layer 14 is not cut when opened and a thin film is formed on the paper container 20. There is a problem that the heat seal layer remains.

  The cohesive release layer 13 and the heat seal layer 14 are preferably formed by coextrusion laminating. The reason for this is that since the aggregated release layer 13 is expensive, the aggregated release is preferably set to the minimum necessary thickness. For this reason, the heat sealing layer 14 is used as a carrier for processing, that is, the aggregated release layer 13. And the heat-seal layer 14 are co-extruded and have the effect of being practical and economical.

  In the paper lid material 10 of the present invention, it is preferable that the weight of the paper base material layer 11 is 51% or more of the total paper lid material 10 in the total weight. By setting the weight of the paper base material layer 11 to 51% or more of the total weight of the paper lid material 10, it can be discarded as a paper classification at the time of separation and collection after use. The reason for this is that the “Law Concerning the Promotion of Separate Collection and Recycling Related to Containers and Packaging (Container and Packaging Recycling Law)” enacted in June 1995 requires container and packaging identification and labeling for the purpose of the separation cycle. As a discrimination method for containers and packaging made up of a plurality of materials, it is based on the fact that the content of classification into the heaviest materials (the ones with the highest ratio on a weight basis) among the materials constituting the containers and packaging is specified.

  Next, the paper lid material of the present invention will be described more specifically with reference to examples.

As an example of the paper lid material of the present invention, 300 g / m ² of cup base paper (Fuji Paper) is used as the paper base layer 11 and LDPE 20 μm (Mirason M16P) is used as the thermoplastic resin intermediate layer 12 by the extrusion laminating method. ; Sumitomo Mitsui Polyolefin Co., Ltd.) was laminated. Next, a 20 μm layer (PB resin: LDPE resin = PB resin: LDPE resin = Tuffmer BL; Mitsui Chemicals, Inc.) and LDPE resin (Mirason M11P; Mitsui Sumitomo Polyolefin Co., Ltd.) are blended as the cohesive release layer 13. 4: 6) and LDPE 5 μm (Mirason M16P; Sumitomo Mitsui Polyolefin Co., Ltd.) were extruded and laminated by tandem COEC as the heat seal layer 14 to obtain a paper lid material having the following configuration.

Paper base material layer 300 g / m ² / thermoplastic resin intermediate layer 20 μm / cohesive release layer 20 μm / heat seal layer 5 μm

<Comparative Example 1>
Using a base paper of 300 g / m ² (Fuji Paper) as a paper base material layer, and extrusion laminating and laminating and laminating LDPE 45 μm (Mirason M16P) as a heat seal layer, a paper lid having the following constitution The material was obtained.

Paper base material layer 300 g / m ² / heat seal layer 45 μm

<Comparative example 2>
Using a base paper of 300 g / m ² (Fuji Paper) as the paper base layer, by extrusion lamination, LDPE 20 μm (Mirason M16P) as the thermoplastic resin intermediate layer and PB resin (Tuffmer BL) as the cohesive release layer A layer (polybutene resin: LDPE resin = 4: 6) 25 μm made of a resin blended with LDPE resin (Mirason M11P) was extruded and laminated to obtain a paper lid material having the following constitution.

Paper base material layer 300 g / m ² / thermoplastic resin intermediate layer 20 μm / cohesive release layer 25 μm

The paper lid materials of Example, Comparative Example 1 and Comparative Example 2 were heat sealed at the flange portion of a paper container having a configuration of (outer surface side) LEPE 15 μm / cup base paper 300 g / m ² / LDPE 40 μm (inner surface side). Then, the opened state of the paper lid was evaluated.
(Heat seal condition)
1. Sealing temperature: 220 ° C., sealing pressure: 20 kpa, sealing time: 1 sec
2. Sealing temperature: 240 ° C., sealing pressure: 20 kpa, sealing time: 1 sec

<Result>

  In Comparative Example 1, the paper container and the cover material were smudged under both heat sealing conditions shown in “Table 1” and “Table 2”.

  In Comparative Example 2, the heat seal condition 2 in “Table 2” causes paper scumming in the paper container and the lid material in the peeled state, so that the range of suitable seal conditions is extremely narrow, and thus lacks practicality. Met.

  In the examples of the present invention, in both heat-sealing conditions, in the peeled state, the paper was peeled off by the cohesive peel layer, and the paper container and the cover material were not smudged. Further, the sealing strength was 17 kpa and 18 kpa, which was 13.3 kpa · 10 sec or more specified in the “Ministerial Ordinance for Milk”.

  The paper lid material of the present invention can be suitably used as a lid material for paper containers mainly filled with yogurt, dairy products, fruit juice, jelly, etc., and should be discarded as paper classification at the time of separate collection after use. And can be widely used for paper lid materials that are configured to satisfy the standards of “Ministerial Ordinances such as Milk”.

It is a block diagram which shows one Example of embodiment of the paper lid | cover material of this invention. It is a perspective view which shows the state which opens the paper lid | cover material of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Paper lid material 11 Paper base material layer 12 Thermoplastic resin intermediate layer 13 Aggregation isolation layer 14 Heat seal layer 20 Paper container 21 Flange part

Claims (7)

A paper lid material in which a paper container is hermetically sealed and has a function of easy opening, wherein a thermoplastic resin intermediate layer, a cohesive release layer, and a heat seal layer are sequentially laminated on a paper base material layer. The paper lid material according to claim 1, wherein a resin obtained by blending polybutene and low-density polyethylene is used for the agglomerated release layer. The paper lid material according to claim 2, wherein a blend ratio (polybutene / low density polyethylene) of the polybutene and the low density polyethylene is in a range of 2/8 to 8/2. The paper lid material according to any one of claims 1 to 3, wherein low-density polyethylene is used for the heat seal layer. The paper lid material according to any one of claims 1 to 4, wherein the thickness of the agglomerated release layer is in the range of 3 to 30 µm, and the thickness of the heat seal layer is in the range of 3 to 20 µm. . The paper lid material according to any one of claims 1 to 5, wherein the cohesive release layer and the heat seal layer are laminated by a coextrusion laminating method. The paper lid material according to any one of claims 1 to 6, wherein a weight of the paper base material layer is 51% or more in a total weight.

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