JP4073999B2 - Heat sealable lid - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a heat-sealing lid for a food cup-type container, and more specifically, a metal detector composed of paper and resin as a main material, excluding metals such as aluminum foil from the constituent material of the lid. In addition to imparting inspection suitability and heating suitability with a microwave oven, there is no curling, light-shielding properties and good food preservation, and when opening, it can be peeled off at the paper layer or interlayer of the lid In addition, the present invention relates to a heat-sealing lid material having a comprehensively excellent performance that the entire lid material can be opened cleanly and is excellent in disposal property after use.
[0002]
[Prior art]
Conventionally, as a lid for a food cup-type container, for example, a heat sealable lid having a structure of paper / polyethylene / aluminum foil / polyethylene / hot melt layer is generally used. An aluminum foil having a thickness of 15 μm or more is used for the aluminum foil layer of the lid member having this configuration in view of its rigidity, plastic deformability, curl prevention, and the like.
Moreover, in the lid | cover material of the structure which does not use aluminum foil, the structure of paper / adhesive or a polyethylene / 2 axis | shaft stretched plastic film / polyethylene / hot-melt layer is known, for example.
[0003]
[Problems to be solved by the invention]
However, the lid using the aluminum foil can reduce the occurrence of curling due to the rigidity and plastic deformability that are the characteristics of the aluminum foil, and it can also partially open the lid by bending at the time of opening. It has good re-closeability when it is returned, and also has excellent light-shielding properties, etc., but on the other hand, inspection of contamination of metal foreign objects by a metal detector after filling the contents, and heating of the contents by a microwave oven during use In addition, there was a problem that the cost was high and the disposal property after use was such that the incineration remained after incineration but did not decompose when landfilled.
[0004]
In addition, the lid material that does not use the aluminum foil eliminates the disadvantages of using the aluminum foil, but conversely, the advantages of using the aluminum foil are lost and the curling tends to occur, and the lid is opened. At the time, the openability due to the bending of the lid material and the reclosability due to the return of the lid material are lowered, and the light shielding property of the lid material is also lowered, so that there is a problem that the storage stability of the contents is lowered.
[0005]
The present invention has been made in view of the problems as described above, and the object of the present invention is to make the main component of paper and resin except for the metal such as aluminum foil from the constituent material of the lid. This enables inspection with a metal detector and heating with a microwave oven, improves waste disposal after use, reduces curl, and opens by opening the lid when folded, and by returning it. The object of the present invention is to provide a heat-sealing lid material with excellent overall performance, such as good re-closeability, good light-shielding properties, and excellent easy peel properties, with high productivity.
[0006]
[Means for Solving the Problems]
The above problems can be solved by the following present invention.
That is, the invention described in claim 1 is a lid made of a laminated sheet including a paper layer to which a water retention agent is supplied, and the innermost layer is an easy peel resin layer, and the paper layer has a basis weight of 80. a double-sided coated paper ~110g / m ^2,-holding liquid medication is a composition of 85 wt% and ethanol 14% by weight of polyethylene imine 1% by weight of water, the light-shielding property on the inner surface side of at least the paper layer ink layer is laminated, and a light transmittance of a wavelength region of 200~800nm of the lid member is 15% or less, and, the easy peel resin layer, blend polybutene-1 and polystyrene resin to low-density polyethylene The heat-sealing lid material is characterized by being formed by laminating a polyethylene-based easy peel resin film on the light-shielding ink layer surface with an adhesive layer interposed therebetween.
[0007]
By adopting such a configuration, the moisture content of the heat-sealing lid material becomes stable over time because the water retention agent is supplied to the paper layer as the base material. And, in the production of the lid material, a water retention agent is applied to the outer surface side of the paper, dried and supplied, and when the ink and overprint varnish are printed thereon and dried, the outer surface side is Shrinkage and temporarily generate a concave curl on the outer surface side, then, printing a light-shielding ink layer on the inner surface side, and further on the innermost easy-peeling resin layer via an adhesive layer By laminating, this time, some shrinkage occurs on the inner surface side, so that the force to curl concavely on the inner surface side works, the balance of shrinkage can be balanced on both sides of the lid material, preventing the occurrence of curling Can do.
[0008]
The cover material has a light-shielding ink layer laminated at least on the inner surface side of the paper layer, and the light transmittance in the wavelength region of 200 to 800 nm of the cover material is 15% or less. It is easy to prevent deterioration of the oil content in the food and improve the shelf life of the food. Furthermore, since the easy-peeling resin layer is laminated on the innermost layer via the adhesive layer, it is possible to impart heat sealing properties and easy-peeling properties to the lid.
In addition, since no metal such as aluminum foil is used as the constituent material of the lid, it is possible to inspect metal foreign objects with a metal detector and to heat with a microwave oven, which is low in cost and excellent in disposal after use. Yes.
[0009]
Further, the invention described in claim 1, wherein the paper layer is intended to include that it is a double-sided coated paper having a basis weight 80~110g / m ^2.
[0010]
By adopting such a configuration, the paper layer has an appropriate thickness and rigidity, so that it contributes to curl prevention, and at the time of opening, a part of the lid material is folded to form an opening, and the folding is also performed. It is possible to easily close the opening by returning. Furthermore, the paper layer is a double-sided coated paper, and so-called clay coating is applied to both sides thereof, so that the coating layer itself has a certain degree of light shielding properties, and both sides of the paper layer have surface smoothness, The printability is excellent, and it is possible to improve the printing effect of characters and patterns on the outer surface side and to form a uniform film of the light-shielding ink layer on the inner surface side, thereby improving the light-shielding property.
In particular, the inner side light-shielding ink layer also has a sealing effect on the paper surface, so when laminating the innermost easy-peeling resin layer via the adhesive layer, the adhesive is applied to the light-shielding ink layer surface. Even if it is applied, the adhesive is not absorbed by the paper layer and the like, the adhesive can be used effectively, and sufficient lamination strength can be obtained with a small amount of adhesive.
[0011]
In the invention described in claim 1 , the innermost easy-peeling resin layer is an adhesive layer made of a polyethylene-based easy-peeling resin film obtained by blending polybutene-1 and a polystyrene-based resin with low-density polyethylene. It is formed by laminating on the surface of the light-shielding ink layer via
[0012]
Easy-peeling resins are originally formed by blending various resins, so there are many types and various components. For example, if the main component of the main resin is ethylene, it is a polyethylene-based resin. Similarly, in the case of propylene, the easy peel resin can be classified as a polypropylene type easy peel resin, and in the case of styrene, it can be classified as a polystyrene type easy peel resin.
[0013]
Among these, polyethylene-based easy peel resin is relatively versatile in heat sealability for containers of various materials, is excellent in low temperature sealability, has a wide range of seal conditions such as seal temperature, The seal strength can be easily adjusted. This is preferable because it can be suitably used not only for plastic molded containers but also for paper cup containers having polyethylene laminated on the inner surface.
In order to obtain a good easy peel property when used for the lid of a paper cup container using such polyethylene laminated paper, it is necessary to adjust the seal strength to about 200 to 500 g / 15 mm width. Adjustment is also possible.
[0014]
As a specific example of such a polyethylene-based easy peel resin, a low-density polyethylene, an ethylene-vinyl acetate copolymer, a copolymer of ethylene and acrylic acid, or methacrylic acid, or an ester thereof is mainly used. A resin obtained by appropriately blending a styrene polymer, a styrene elastomer, polybutene-1, other tackifiers and the like can be used.
Therefore, by adopting such a configuration, workability of heat sealing is improved, and stable heat sealing properties and easy peel properties can be obtained.
[0015]
In the invention described in claim 2 , the heat sealable cover material is formed by combining a droplet pattern with a heat embossing method so that the outer surface side of the cover material is convex and the inner surface side is concave. The heat-sealing lid material according to claim 1 , wherein the heat-sealing lid material is shaped into a single sheet and is punched into a predetermined shape.
[0016]
The heat-sealing lid material of the present invention can of course be used as a winding-type lid material even in a filling and sealing machine using a winding-type lid material, but by adopting the above-described configuration. Even if heat-sealing lid materials punched on sheets are stacked, the contact area between the lid materials decreases, so that there is no blocking, and the sliding property between the front and back surfaces of the lid material is also improved. Therefore, even if it is used in an automatic filling and sealing machine that uses a single-wafer-type lid material, the lid material is suitable for feeding and can be used satisfactorily without trouble such as inserting two sheets.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Next, the configuration of the heat-sealing lid material of the present invention and the embodiment thereof such as a manufacturing method will be described with reference to the drawings.
FIG. 1 and FIG. 2 are schematic cross-sectional views showing the configuration of one embodiment of the heat-sealing lid material of the present invention. However, the present invention is not limited to these drawings.
[0018]
The heat sealable cover material 10 shown in FIG. 1 has a paper layer 1 supplied with a water retention agent as a base material, and an ink layer 2 such as letters and pictures is printed on the outer surface thereof, and a transparent overcoat is formed thereon. The print layer 3 is printed, and the light-shielding ink layer 4 is laminated on the inner surface side of the paper layer 1 by printing or coating means, and the innermost easy-peeling resin layer via the adhesive layer 5 thereon. 6 is laminated.
[0019]
In the above configuration, the paper layer 1 is a base material for the heat-sealing lid member 10 and has rigidity, excellent mechanical strength such as tensile strength and tear strength, and interlayer strength, and printing on both sides thereof. In view of the fact that an ink layer is provided, the printability is preferably excellent.
Therefore, although not particularly limited, for example, a double-sided coated paper having a basis weight of about 80 to 110 g / m ² and a so-called clay coat on both sides can be suitably used.
When the basis weight is less than 80 g / m ² , the rigidity and mechanical strength are insufficient, so the lid material is likely to be curled or torn, and when the basis weight exceeds 110 g / m ² , the rigidity is increased. Is already sufficient, there is no need for it, it takes time for heat sealing, and the interlaminar strength of the paper tends to decrease.
[0020]
Moreover, as a water retention agent supplied to the paper layer 1, a water retention agent mainly composed of water, alcohols, polyethyleneimine, or the like can be used, and as alcohols, methanol, ethanol, isopropyl alcohol, butanol or the like is used. can do.
Specific examples of the water retention agent include a water retention agent having a composition such as 85% by weight of water, 14% by weight of ethanol, and 1% by weight of polyethyleneimine.
A method of supplying such a water retaining agent to the paper layer 1 is to use a multicolor gravure printing machine in the first unit when printing characters, designs, etc. on the outer surface side of the paper layer 1 by, for example, gravure printing. Print the water retention agent using a solid plate, dry excess water and alcohol, and then print the characters, pictures, etc. and print the overprint varnish, and print the water retention agent inline with the outer surface side print. Layer 1 can be fed.
[0021]
Next, the light-shielding ink layer 4 laminated on the inner surface side of the paper layer 1 is provided to improve the light-shielding property of the lid material and improve the preservability of the contents such as food. It is preferable that light in the wavelength region of 200 to 800 nm is absorbed or reflected to block the light, and the light transmittance of the lid material in this wavelength region is 15% or less.
As a pigment used for such a light-shielding ink layer 4, for example, a black pigment such as carbon black can be substantially shielded from light even if used alone.
However, even on the inner surface of the lid material, the black pigment alone is not necessarily preferable as a lid material for food containers in terms of design and image.
[0022]
Therefore, it is preferable to use a combination of a black pigment and a white pigment because both the light shielding property and the design property of the lid material can be achieved.
In this case, the method for providing the light-shielding ink layer 4 may be, for example, printing the ink prepared by mixing a black pigment and a white pigment to provide the light-shielding ink layer 4, or using a black pigment. A black ink and a white ink using a white pigment may be prepared separately, and the black ink may be printed first, and the white ink may be overprinted on the black ink layer so as to conceal the black ink layer. .
[0023]
As the white pigment used for such a light-shielding ink layer 4, titanium dioxide, zinc white, calcium carbonate, clay (kaolin), barium sulfate and the like can be used, and these white pigments are mainly 390 nm or less. Ultraviolet light can be effectively shielded.
In addition to carbon black, the following black or white organic or inorganic pigments can be used in appropriate combination. Specifically, as organic pigments, phthalocyanine pigments, insoluble azo pigments, azo lake pigments, anthraquinone pigments, quinacridone pigments, dioxazine pigments, diketopyrrolopyrrole pigments, anthrapyridine pigments, ansanthrone pigments, indanthrone pigments, flavanthrone pigments Perinone pigments, perylene pigments, isoindolinone pigments, thioindigo pigments, and inorganic pigments include iron oxide, ultramarine blue, bitumen, cobalt oxide, strontium chromate, titanium yellow, zinc chromate, iron black, molybdenum red, emerald green , Cadmium yellow, cadmium red, cobalt blue and the like.
[0024]
Such a light-shielding ink layer 4 can be additionally provided below the ink layer 2 such as characters and patterns on the outer surface side of the paper layer 1 as necessary.只 In that case, it is necessary to consider the color tone to such an extent that the design properties such as the pattern on the outer surface side are not impaired.
Such a light-shielding ink layer 4 may be provided by a coating means in addition to a printing means, and the coating amount is preferably 4 to 10 g / m ² in terms of solid content.
[0025]
Next, an innermost easy-peeling resin layer 6 is laminated on the light-shielding ink layer 4 with an adhesive layer 5 interposed therebetween.
As a method of laminating an easy peel resin layer, in general, an anchor coat agent is applied to the laminate surface, and then an easy peel resin is extruded and laminated, as well as polyethylene and other polyolefin resins. Extrusion lamination method (also called sandwich lamination method) in which an easy-peelable resin film formed in advance is pressed and laminated with a roll while extruding the adhesive resin onto the laminated surface. For example, there is a dry lamination method in which an easy-peeling resin film formed in advance through an agent is bonded.
[0026]
Both of the previous two methods are not preferable because the melted resin is coated on the laminated surface, so that the resin shrinks after lamination and the curl of the lid becomes large. In this respect, the third dry lamination method is not exposed to a high temperature such that the resin melts at the time of lamination, and the adhesive coating surface is a light-shielding ink layer surface on the substrate side, Since the tension applied to the easy-peeling resin film can also be reduced, there is no significant shrinkage after bonding, and a curl-free lid can be produced.
[0027]
Therefore, in the present invention, a dry lamination method is adopted, an adhesive for dry lamination is applied to the surface of the light-shielding ink layer 4, and an easy peel resin film previously formed thereon is bonded and laminated. It is.
For such an adhesive layer 5, for example, a known polyurethane adhesive composed of a polyol component and a polyisocyanate component can be used, and for the easy peel resin layer 6 as described above. It is preferable to use a film in which a polyethylene-based easy peel resin is formed in advance, and the thickness is suitably in the range of 25 to 40 μm.
[0028]
The heat-sealing lid material 20 shown in FIG. 2 is the same as the heat-sealing lid material 10 shown in FIG. In addition, the lid member 20 is formed by forming a concavo-convex pattern.
Such a concavo-convex pattern is provided in order to improve the blocking resistance of the lid member 20 and the feeding suitability of the lid member 20 in the case of a single wafer form in the filling and sealing machine. The shape is not limited, and a shape in which a gap is formed between the cover materials 20 that overlap each other in a wound shape or in a single-wafer shape, can reduce the contact area, and does not impair the slipperiness of the stacked cover materials 20. Any shape can be provided.
[0029]
In the lid member 20 shown in FIG. 2, the concavo-convex pattern is relatively large and is formed so as to cover the entire layer of the lid member 20 as shown by the concavo-convex portions 7 and 7 ′. It can be finely formed like a cloth shape, a line shape, or the like, and can be provided so as to be formed only on either the inner surface or the outer surface of the lid member 20.
It is not necessary to increase the difference in height between the concavo-convex portions. In particular, in the case where the concavo-convex pattern has a fine texture, a line, etc., it is sufficient if it is about 5 to 25 μm.
Moreover, the method of providing an uneven | corrugated pattern can be easily provided by the well-known embossing method.
[0030]
【Example】
Hereinafter, the present invention will be described more specifically with reference to examples.
Example 1
The heat-sealing lid material 10 having the configuration shown in FIG. 1 is prepared, and a double-sided coated paper having a basis weight of 90 g / m ² is used as a base paper, and a multicolor gravure printing machine is used on the outer surface side. The first unit supplies 85% by weight water, 14% by weight ethanol, and 1% by weight polyethyleneimine, printed on a solid plate with a plate depth of 25 μm, dried, and supplied. The ink layer 2 and the overprint layer 3 were printed. In this step, a part of the water retention agent is dried from the outer surface side of the paper layer 1.
[0031]
Next, using a multicolor gravure printing machine on the inner surface side of the paper layer 1, a gray ink prepared by adding a pigment of a mixed system of carbon black and titanium oxide was used to obtain 2 Overprinting was performed in the unit, and a light-shielding ink layer 4 having a coating amount of 6 g / m ² (solid content) was provided.
Next, a two-component curable polyurethane adhesive is used as the adhesive layer 5 on the light-shielding ink layer 4 by a dry lamination method so that the coating amount when dried is 3 g / m ^2. Then, after removing the solvent component by hot air drying, as the innermost easy-peeling resin layer 6, a low-density polyethylene blended with polybutene-1 and a polystyrene-based resin has a thickness of 30 μm. A peelable resin film was laminated and laminated to produce the heat-sealing lid material 10 of Example 1.
[0032]
(Example 2)
The heat-sealing lid material 20 having the configuration shown in FIG. 2 is produced, and an embossed plate having a pattern in which droplet patterns are combined with the heat-sealing lid material 10 produced in Example 1 by the hot embossing method. The embossed pattern was embossed in the direction in which the outer surface side of the lid member 20 swelled to form a concavo-convex pattern, and the heat sealable lid member 20 of Example 2 was produced.
In addition, the height of the convex part on the outer surface side of the lid member 20 and the depth of the concave part on the inner surface side are approximately 20 μm.
[0033]
Each heat-sealing lid material of Examples 1 and 2 produced as described above was punched into a shape having a circular shape with a diameter of 100 mm and a knob piece on a part of the outer periphery to produce a single-wafer-type lid material. Each light shielding property, curl condition, and easy peel property after heat sealing were examined as follows.
[0034]
(1) As a result of measuring the light transmittance in the wavelength region of 200 to 800 nm using a light-shielding self-recording spectrophotometer UV-2200 (manufactured by Shimadzu Corporation), each sample of Examples 1 and 2 has a light transmittance of 10 % Or less was good.
[0035]
(2) Measurement of curl Randomly 20 samples were taken for each cover material, and placed on a horizontal glass plate with the cover surface facing upward, the height of the highest part (mm ) And the average value was taken as the curl value.
As a result of the above measurement, the curl value was as small as 4 mm and good for each of the samples of Examples 1 and 2.
In addition, as a past record, when the curl value is 5 mm or less, the mechanical suitability of the automatic filling and sealing machine is good.
In particular, since the concave / convex pattern is formed on the lid material of Example 2, in addition to small curl, it also has blocking resistance and moderate slipperiness, and uses a single-sheet lid material. The automatic filling and sealing machine could be used satisfactorily without any problems.
[0036]
(3) Easy peel property Each lid material of Examples 1 and 2 is pressure-bonded at 140 ° C. with a ring sealer at a pressure of 6 kg / cm ^{2 on} the flange portion (bonding surface is polyethylene) of a paper cup container laminated with polyethylene on the inner surface. Heat sealing was performed under the condition of time 1.0 seconds, and after 1 day, the lid material was peeled off, and the state of the peeled portion and the easy peel property were examined.
As a result, in both cases, the peeling part is between the easy-peeling resin layer of the lid material and the flange part (polyethylene layer) of the container, and the peeling surface is not broken without the interlayer of the lid material or container being destroyed. It was in a beautiful state. Also, the easy peel property was good because it could be peeled off with an appropriate strength.
[0037]
【The invention's effect】
As described above in detail, according to the present invention, the preservability of contents such as food is provided with light-shielding properties, and there is no curl as a single-sheet cover material punched one by one, and an automatic filling and sealing machine It has good mechanical suitability and has good heat sealability and easy peelability. In addition, the metal detector is inspected for contamination by a metal detector after the filling and sealing of the contents, and the contents are heated by a microwave oven. In addition, there is an effect that it is possible to provide a heat-sealing lid material with excellent productivity and suitability for use with good productivity, such as excellent disposal after use.
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional view showing the configuration of an embodiment of a heat-sealing lid material of the present invention.
FIG. 2 is a schematic cross-sectional view showing the configuration of another embodiment of the heat-sealing lid material of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Paper layer to which water retention agent was supplied 2 Ink layer for characters, patterns, etc. 3 Overprint layer 4 Light-shielding ink layer 5 Adhesive layer 6 Easy peel resin layer 7, 7 ′ Concavity and convexity 10, 20 Heat-sealing lid

Claims (2)

In a cover material using a laminated sheet that includes a paper layer supplied with a water retention agent and whose innermost layer is an easy peel resin layer, the paper layer is a double-sided coated paper having a basis weight of 80 to 110 g / m ^2. There,-holding liquid medication is a composition of 85 wt% and ethanol 14% by weight of polyethylene imine 1% by weight of water, the light-shielding ink layer on the inner surface side of at least the paper layer is laminated, 200 of the lid member A film of a polyethylene-based easy-peeling resin having a light transmittance of 15% or less in a wavelength region of ˜800 nm and the easy-peeling resin layer blended with low-density polyethylene and polybutene-1 and a polystyrene-based resin. heat sealing properties lid, characterized in that it is formed by laminating a light-shielding ink layer surface through the adhesive layer. The heat-sealing lid material is shaped by a hot embossing method into a concave / convex pattern in which droplet patterns are combined so that the outer surface side of the lid material is convex and the inner surface side is concave. The heat-sealing lid material according to claim 1 , wherein the sealing lid material is in the form of a single wafer punched into a predetermined shape .

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