JPH09300544A - Heat sealable cover material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat sealable cover material in which metallic material such as aluminum foil is not contained, product inspection through a metal detector is enabled, disposal properties after use are excellent, water resistance, heat resistance and easy peel properties are excellent, curling is not caused even in the cover material of a sheet form, and mechanical suitability of a filling/sealing machine is excellent. SOLUTION: A base material sheet is formed by laminating biaxially stretched plastic films 2a, 2b on both sides of paper 1 through adhesives 4a, 4b. The heat sealable cover material 10 is constituted by providing an easily peelable sealant layer consisting of easily peelable resin or hot melt 6 on one- side face. Machine glazing bleached kraft pulp is favorable for paper 1 used for the base material sheet and biaxially stretched polyethylene terephthalate film is favorable for the plastic films 2a, 2b. Further, a dry laminating method is favorable for laminating of the base material sheet. Coverage of the adhesives 4a, 4b favorably is 4-10g/m<2> (solid part) on both sides.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a polypropylene,
Regarding heat-sealing lid material used for plastic molding containers made of polystyrene, polyethylene, etc., or made of laminated sheets, more specifically, except paper such as aluminum foil from the constituent material of the lid material, mainly paper and plastic Composed of materials, yet water resistant, does not curl, does not expand due to heat during sealing, and
The present invention relates to a heat-sealing lid material having excellent performance that the entire lid material can be easily opened without peeling between paper layers or layers during opening.

[0002]

2. Description of the Related Art Conventionally, cup-shaped containers have been used for dessert foods such as yogurt, pudding, jelly, ice cream, frozen desserts, liquid beverages such as fruit juice, coffee, cocoa, milk drinks, and instant noodles and snacks. It has been used in a wide range of fields such as food. Most of the lid materials used for these containers are sealed by heat sealing in terms of the storability and hygiene of the contents, and also have an easy peel property in terms of convenience during use. Is essential.

Therefore, as one of the important functions of the lid material,
A well-balanced adhesive strength of the lid to the container body that it does not peel off during the distribution stage of the product, and is neither too weak nor too strong so that it can be easily opened during use. Is required. From this point,
As for the configuration of the lid material, an optimal one is appropriately selected and used depending on the material and contents of the container body, usage conditions and the like.

In particular, the following structure is known as a structure of a lid member having a base material of paper or a laminate containing paper as a base material. Paper / polyethylene / aluminum foil / polyethylene (hereinafter polyethylene is referred to as PE) Paper / PE / aluminum foil / PE / hot melt Paper / adhesive or PE / biaxially stretched plastic film / PE / hot melt

[0005]

The structure of the above-mentioned lid material is as follows.
Each of them has been created in response to the demand for various functions for the lid material, but nevertheless there is a common drawback that the range of sealing conditions is narrow in order to obtain a good sealing state in actual use. Was. That is, during heat-sealing, the sealing device and other problems cause excessive sealing conditions, for example, when high temperature or high pressure is applied, the paper layer of the lid material is broken or the lid material is broken during opening. There is a drawback that the entire lid material cannot be peeled off cleanly due to peeling between the layers.

In addition to this, there is a common problem that curling is likely to occur as a lid material, and in the case of an apparatus of a type in which a sealing device supplies a wound lid material, heat seals it, and cuts, it is relatively problematic. However, in the case of an apparatus of a type in which a sheet of lid material punched out in advance is supplied and heat-sealed, there is a problem that the lid material cannot be smoothly supplied from the feeder portion if there is curl. Further, since the paper is the outermost layer, the water resistance is insufficient, and particularly when it is used for refrigerated or frozen products, there is a problem that water is absorbed and unevenness is generated on the surface of the lid material, and the appearance is impaired. .

In the food-related field, after filling and sealing the contents, a metal detector is inspected as part of quality control in order to prevent foreign matter from entering. There is also a problem that the inspection by the metal detector cannot be performed because the aluminum foil is used for the. Further, when a metal such as aluminum foil is used, there is a problem in disposability after use, and therefore there is an increasing demand for removing aluminum foil from the constituent materials.

The present invention has been made in view of the above problems, and an object of the present invention is to remove the aluminum foil from the constituent material of the lid material and to use a material mainly made of paper and plastic. By doing so, inspection with a metal detector is possible, and the disposability after use is improved, and also in terms of performance, water resistance and heat resistance (heat seal stability) are improved, and curling hardly occurs. It is an object of the present invention to provide a heat-sealing lid material that can be favorably used even in a filling / sealing machine that uses a sheet lid material.

[0009]

The above objects have been achieved by the present invention described below. That is, the invention according to claim 1 is such that an easy peelable resin layer or a polyolefin resin is provided on one surface of a base sheet obtained by laminating biaxially stretched plastic films on both sides of a paper with an adhesive. One of the hot-melt layers is provided via an adhesive layer made of a heat-sealing lid material.

The invention according to claim 2 is characterized in that the amount of the adhesive used for laminating the base sheet is 4.0 to 10.0 g / m ² in terms of solid content on both sides. The heat-sealing lid material according to claim 1. Further, the invention according to claim 3 is characterized in that, in the heat-sealing lid material, at least the outermost biaxially stretched plastic film has an antistatic property. It consists of a sex lid material. Furthermore, the invention according to claim 4 is characterized in that the heat-sealing lid member is in the form of a sheet that is punched into a predetermined shape in advance, and the heat-sealing material according to any one of claims 1 to 3. It consists of a sex lid material.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of the heat-sealing lid material of the present invention, such as a constituent material and a manufacturing method thereof, will be described. In the heat-sealing lid material of the present invention, the paper serves as a base material, and a biaxially stretched plastic film is laminated on both surfaces thereof with an adhesive to form a base material sheet, and further, on one surface thereof. A sealant layer having an easy peel property is provided and used. By laminating biaxially stretched plastic films on both sides of the paper in this manner, the weakness of the paper, that is, the water resistance is supplemented, and the safety against curling can be enhanced, but on the other hand, a film having no breathability is used. Since both sides are shielded, the heat generated during heat sealing causes the air contained in the paper layer to expand rapidly and the water contained in the paper to evaporate, causing the cover material to expand. There was a drawback that made it easier.

In order to eliminate this drawback, in the lid material of the present invention, when the biaxially stretched plastic film is laminated on both sides of the paper, the adhesive coating amount is set to be larger than usual so that the fibers of the paper and the interlayer of the paper are laminated. Also, the adhesive is permeated and strengthened to prevent the occurrence of blistering. Therefore, the paper has rigidity as a base material, has a uniform thickness, is excellent in smoothness and flatness (no curl), and at the same time, the paper itself has good entanglement between fibers and strong interlaminar strength. It is preferable that the adhesive easily penetrates and the strength between the fibers and between the layers can be enhanced. As the paper having such performance, for example, commercially available paper is preferably kraft-based paper, and particularly preferably single gloss bleached kraft.

Conventionally, when paper is used as the lid material, it is used as the outermost layer, so that printability is also required, and coated paper has also been used. However, in the configuration of the lid material of the present invention, since the biaxially stretched plastic film is used as the outermost layer, it is more preferable to print on this film in the back-printing form from the viewpoint of enhancing the printing effect, and not printing on paper. Therefore, printability is not particularly required. Further, in the case of coated paper, the heat resistance and solvent resistance of the coat layer are not so strong, so that there is a risk of peeling of the coat layer, and penetration of the adhesive into the paper layer is also hindered, which is rather undesirable. Similarly, printing on the paper side is also not preferable because the printing layer impedes the penetration of the adhesive into the paper layer, and the reinforcing effect of the paper layer decreases.
In order to make the pattern printed on the film clearer and to further enhance the printing effect, it is preferable that the paper on the back side is white. From this point, the bleached kraft that has been subjected to the bleaching treatment is more suitable. There is. The thickness of the paper is 30 to 11 in terms of rice basis weight.
Preferably having from 0 g / m ^2, further preferably from 60 to 90 g / m ^2. If the basis weight is less than 30 g / m ² ,
When the rigidity is insufficient and exceeds 110 g / m ² , the rigidity is already sufficient and there is no need for it, and rather the heat sealing conditions become more severe and the risk of blistering increases, and It is not preferable because the strength tends to decrease.

The biaxially stretched plastic film laminated on both sides of the paper with an adhesive improves the water resistance by covering the surface of the paper, and the expansion and contraction of both sides are minimized and the balance is improved. By taking it, curl is prevented and at the same time mechanical strength such as tensile strength and heat resistance are improved, and the entire lid material is peeled off cleanly together with the easy-peel sealant layer without breaking the paper layer when opening. It is used for. Therefore,
In addition to mechanical strength, it is necessary to have excellent water resistance, heat resistance, and dimensional stability. Specifically, biaxially stretched polybutylene terephthalate film, biaxially stretched polyester film such as biaxially stretched polyethylene terephthalate film, 2 An axially stretched nylon film and a biaxially stretched polypropylene can be preferably used, but a biaxially stretched polyethylene terephthalate film is particularly preferable. still,
If it is desired to add a gas barrier property to the lid material, these biaxially stretched plastic films may be coated with polyvinylidene chloride, or an inorganic thin film such as silicon oxide may be provided by vapor deposition or the like.

The heat-sealing lid material of the present invention can be used not only in a filling and sealing machine for supplying a winding lid material, but also for a filling and sealing machine for feeding a sheet-shaped lid material punched into a predetermined shape in advance. It was made available and for this purpose,
The lid material punched out in a sheet shape is required not only to have no curl but also to have appropriate slipperiness. Regarding the slidability, the material on both the front and back surfaces of the lid material and fine irregularities on the surface are also related, but the electrostatic chargeability also has a great influence. That is, when the amount of charge is large in a state where the lid materials are stacked, the lid materials are in close contact with each other, and the feeder of the sealing device cannot accurately feed the sheets one by one, which causes a feeder trouble such as two sheets.

Therefore, in the biaxially stretched plastic film laminated on both sides of the paper, at least the surface opposite to the surface on which the sealant layer is provided, that is, the outermost surface of the lid member,
It is preferable to use a biaxially stretched plastic film having antistatic properties. Of course, a normal biaxially stretched plastic film which is not particularly provided with antistatic property can be used for the outermost layer surface of the lid material, but in that case,
Since the lid material is likely to be charged in the dry season such as winter, it is necessary to take measures such as attaching a static eliminator to the feeder of the sealing device. In this respect, when the biaxially stretched plastic film having antistatic property is used, it is possible to always stably supply the lid material without requiring a special device such as a static eliminator.

As a method of laminating such a biaxially stretched plastic film on both surfaces of paper, a dry lamination method using a conventionally known two-component reactive adhesive or the like, or a lamination using a non-solvent type adhesive is used. Or a extrusion laminating method in which a polyolefin resin such as polyethylene is used as an adhesive instead of the adhesive, the dry laminating method is the most preferable in the present invention in terms of performance and economy. That is, by using the dry laminating method and increasing the amount of adhesive applied as compared with the case of laminating films to each other, the adhesive permeates between the fibers of the paper and between the layers to fix it, and Since the moisture content of the paper can be lowered by the heat of drying, the surface strength and interlayer strength of the paper are strengthened at the same time as the film and the paper are adhered, and the heat of the sealing causes the paper to swell and the paper when opened. It is effective in preventing delamination.

As the adhesive used for such dry lamination, for example, a polyurethane-based two-component reactive adhesive or the like can be used, and the coating amount thereof is 4.0 to 1 in terms of solid content.
0.0 g / m ² is preferable, and 4.5 to 6.0 g / m ² is more preferable. If the coating amount is less than 4.0 g / m ² ,
The penetration of the adhesive into the paper is small, the interlaminar strength of the paper is not sufficiently strengthened, and the high temperature seal easily causes expansion, which is not preferable. Further, if the coating amount exceeds 10.0 g / m ² , so-called laminate wrinkles are likely to occur, which is not preferable. By the above method, a base sheet in which a biaxially stretched plastic film is laminated on both sides of paper can be prepared.

The heat-sealing lid material of the present invention can be prepared by providing an easy peeling sealant layer on one surface of the base sheet prepared as described above. The easy-peel sealant itself is not particularly limited, and any conventionally known sealant can be used. That is, when using a hot melt material as an easy peeling sealant, in order to improve the adhesiveness with the base material sheet, first, an adhesive layer made of a polyolefin resin is provided on the base material sheet surface by extrusion coating, etc. An easy-peel sealant layer can be provided by applying a hot-melt material on the top with a molten gravure coat or the like.

In the above, as the polyolefin resin for the adhesive layer, in addition to polyethylene, the ethylene component is 80 to 95% by weight, and the remaining 20 to 5% by weight is carboxylic acid or its ester component. The following copolymer resin can be used. Incidentally, as the carboxylic acid, vinyl acetate, acrylic acid, methacrylic acid and esters thereof are preferable.

The hot melt layer provided on the polyolefin resin layer is preferably applicable as a wide range of easy peel sealants to containers made of different materials such as polypropylene, polystyrene and polyethylene. From this point, for example, a vinyl acetate content of 10
~ 40 wt% ethylene-vinyl acetate copolymer 30 ~
50% by weight and waxes (microcrystalline wax alone or a mixture thereof with other wax) 30 to 4
For example, a resin formed by melt mixing in an amount of 0% by weight, a tackifier of 15 to 30% by weight, and if necessary, other additives up to 10% by weight can be used.

As the tackifier, hydrogenated rosin,
Rosin resin, petroleum resin, terpene resin, cumarone
Indene / styrene-based resins, isoprene-based resins, and the like can be used and can be appropriately selected from these. Other additives are a lubricant, an anti-blocking agent, a heat stabilizer, and the like. Examples of the lubricant and the anti-blocking agent include fatty acid esters, amides, amines, and fine powders of inorganic compounds. Examples of the agent include butylhydroxytoluene, tocopherols, n-octadecyl-β
(4'-Hydroxy3 ', 5-di-t-butylphenyl) propionate and the like, and a suitable one can be selected from these known ones.

Such a hot melt layer can be formed not only by a melt gravure coating method in which a hot melt material melted by heating is applied by a gravure cylinder, but also by a melt extrusion coating method. In the lid material of the present invention, the melt gravure coating method is used. Is preferred. Application amount is 10g / m ²
The range is preferably 40 to 40 g / m ² , and usually 20 to 30 g.
/ M ² or so.

As a method of providing the easy-peel sealant layer on the base sheet, there is a method of using an easy-peel resin in addition to the method of using the hot melt material. As the easy peeling resin, for example,
A resin obtained by blending a polyolefin-based resin and a styrene-based resin, or a resin obtained by further blending a polyolefin-styrene copolymer therewith, and a tackifier for a polyolefin-based resin such as an ethylene-vinyl acetate copolymer (the above-mentioned. It is possible to use a resin obtained by blending the same as the constituent components of the hot-melt material).

As a method for laminating these resins on a base sheet, a resin is formed into a film in advance by an extrusion method using a T die or an inflation molding method, and the film is dried by a dry lamination method using an adhesive. A method of laminating, or a method of laminating the film by extrusion laminating method using polyethylene or other polyolefin resin as an adhesive layer, further, after applying an anchor coat (primer coat) as an adhesive layer to a base sheet, then an easy peel There is a method of directly extruding and coating a hydrophilic resin and laminating, and any method may be used.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below with reference to the drawings and embodiments. However, the present invention is not limited to the drawings and the embodiments. 1 and 2 are schematic cross-sectional views showing the configuration of one embodiment of the heat-sealing lid material of the present invention. In FIG. 1, the heat-sealing lid material 10 has a paper 1 as a base material, and biaxially stretched plastic films 2a, 2b are laminated on both surfaces thereof with adhesives 4a, 4b to form a base material sheet, A polyolefin resin layer 5 is provided on one surface as an adhesive layer, and then a hot melt layer 6 is provided thereon. When the printed pattern is provided on the heat-sealing lid material 10, it is preferable to previously provide the printed pattern layer 3 on the inner surface (laminated surface) of the biaxially stretched plastic film 2a which is the outermost layer of the lid material. For example, it is possible to print on the surface of the paper 1, but in that case, it is not preferable because the penetration of the adhesive 4a into the paper is hindered. Further, it is preferable to use a film having an antistatic property as the biaxially stretched plastic film 2a which is the outermost layer of the lid member.

The heat-sealing lid material 11 shown in FIG.
The procedure is the same as that of FIG. 1 until the base sheet is prepared by laminating the biaxially stretched plastic films 2a and 2b on both sides of the paper 1 with the adhesives 4a and 4b, respectively. When the printed pattern layer 3 is provided on the inner surface of the biaxially stretched plastic film 2a, this film is used as the outermost layer of the lid material, and the biaxially stretched plastic film 2b on the opposite side is provided with the adhesive layer 7 on the other side. Peelable resin layer 8
It is configured by stacking.

The present invention will be specifically described below with reference to examples. (Example 1) As a base paper, a single-glazed kraft having a basis weight of 80 g / m ² was used, and one surface (gloss side) had a thickness of 1
Biaxially stretched polyethylene terephthalate film having an antistatic property of 2 μm [T-6142 Toyobo Co., Ltd.
Made] (printed), and on the other side, thickness 1
2 μm ordinary biaxially oriented polyethylene terephthalate film [T-4200 (double-sided treatment) manufactured by Toyobo Co., Ltd.]
When a two-component reactive polyurethane adhesive (a mixture of Takelac A-969 (main agent) and Takenate A-5 (curing agent) manufactured by Takeda Pharmaceutical Co., Ltd. in a weight ratio of 3: 1) was dried respectively. using as the amount of coating is 4.5 g / m ^2, and its printing surface and the paper surface in the case of the printed film (T-6142), was bonded by dry lamination to create the base sheet .

Next, an anchor coat is applied to the usual biaxially stretched polyethylene terephthalate film [T-4200 (double-sided treatment)] side of the above-mentioned substrate sheet, and then an ethylene-methacrylic acid copolymer [as a polyolefin resin layer [ Nucrel 1108C manufactured by Mitsui DuPont Polychemicals Co., Ltd.] with a melt extrusion coating method to a thickness of 20 μm
So that the hot melt material [H
-301A manufactured by Toyo Petrolite Co., Ltd.] was applied by a melt gravure coating method so that the coating amount was 25 g / m ² to form a hot melt layer, and the heat-sealing lid material sheet of Example 1 was prepared. . (Hereinafter, a biaxially stretched polyethylene terephthalate film is referred to as a PET film.)

(Example 2) In the constitution of the heat-sealing lid material sheet of Example 1, the same process as in Example 1 was performed until the base sheet was prepared, and the ordinary PET film [T
-4200 (double-sided treatment)] side, a film obtained by previously forming an easy peel resin as an easy peel sealant layer is laminated by a dry lamination method,
30 μm thick easy-peel resin film [CMP
S-011C (a resin film composed of an ethylene-vinyl acetate copolymer blended with a tackifier, etc.) manufactured by Tohcello Chemical Co., Ltd.] was used as the PET film [T-4200].
(Double-sided treatment)] A dry laminator was used to coat the surface with the same two-component reactive polyurethane adhesive as the adhesive used for laminating the base sheet, and the coating amount at the time of drying was 3 g / m 2.
² so as applied to prepare a heat-sealing properties lid sheet of Example 2 by laminating dry.

Comparative Example 1 In the constitution of the heat-sealing lid material sheet of Example 1, the coating amount of the adhesive used for laminating the base material sheets was 3.5 g / m ² on both sides. The heat-sealing lid material sheet of Comparative Example 1 was prepared in the same manner as in Example 1 except that the heat-sealing lid material sheet was laminated in the same manner as described above.

(Comparative Example 2) In the constitution of the heat-sealing lid material sheet of Example 1, in order to change the paper of the base material to the high-quality paper of the basis weight of 80 g / m ² and to further laminate the PET film on both sides thereof. Heat-sealing of Comparative Example 2 was carried out in the same manner as in Example 1 except that the amount of adhesive used was laminated such that the amount of adhesive applied on both sides was 3.5 g / m ² when dried. A sex lid material sheet was created.

(Comparative Example 3) In the construction of the heat-sealing lid material sheet of Example 2, the outermost PET film, that is, the thickness of 12 μm laminated on the glossy surface of the single-sided bleached kraft of the substrate.
PET film with antistatic properties (T-6142)
The heat-sealing lid material sheet of Comparative Example 3 was prepared in the same manner as in Example 2 except that the use of (printed) was stopped and the pattern printing was directly printed on the surface of the paper.

(Evaluation Test and Results) The heat-sealing lid material sheets of Examples 1 and 2 and Comparative Examples 1, 2 and 3 prepared as described above were pinched on a part of the outer circumference in a circular shape having a diameter of 100 mm. Punching was performed on a lid member having a piece with a shape, and each sample was used for an evaluation test, and the following test was performed. The number of created samples is 1000 each.

[Test Items] (1) Curl Measurement Randomly, 20 lid materials were sampled randomly for each of the above-mentioned samples, and the lid materials were placed one by one on a horizontal glass plate, and the highest portion The height (mm) was measured, and the average value was used as the curl value. The evaluation standard of curl is as a conventional result,
When the curl value is 5 mm or less, the mechanical aptitude of the filling and sealing machine is good. When the curl value exceeds 5 mm, poor mechanical aptitude such as a feeder trouble tends to occur.
The results are shown in Table 1 by symbols, in which the result is indicated as good [○] when the value is not more than m and as poor [x] when the value exceeds 5 mm.

(2) Thermal expansion resistance The heat sealing of the lid material is usually carried out by using a ring sealer or the like at a temperature of the hot plate of 130 to 150 ° C., a pressure of 6 kg / cm ² , and a pressure bonding time of about 1 second. However, when the contents filled in the container are frozen products such as frozen desserts, heat sealing is performed at a high temperature of the hot plate of 260 to 270 ° C. In such a case, when paper is included in the constituent material of the lid member, the layers of the paper and the like are peeled off due to expansion of moisture and air contained in the paper layer, and a blistering state is likely to occur. Therefore,
The outer diameter of the flange is 10
Fill a 0 mm polypropylene cup container with ice cream,
The lid material for each sample was heated to a temperature of 270 ° C. and a pressure of 6 kg / c.
Heat sealing was performed under conditions of m ² and time of 1 second (severe conditions), and the presence or absence of blistering in the sealed portion was examined. (The number of samples is 20 each.) The evaluation criteria are [○] for those without blisters, [△] for those with a slight blisters, and [△] for those with a lot of blisters. X] is indicated by a symbol in Table 1.

(3) Easy Peelability Similar to the test of the heat-resistant blistering property, a polypropylene cup container was filled with frozen dessert, and only the hot plate temperature was 260 ° C. (freezing) in the heat sealing conditions of the lid material. (Standard sealing temperature for products), heat seal, freeze-store for 1 day, and then open, evaluate the easy peeling property of the lid material and the peeling condition of the seal part according to the following criteria, and the results are shown in Table 1. Is indicated by a symbol. (The number of samples is 20 each.) It is good that the lid material can be peeled off with an appropriate peeling strength, the base material sheet of the lid material is not broken, and the peelable sealant layer can be peeled off smoothly. When the peel strength was too strong or the base sheet of the lid material was broken in a portion other than the easy peel sealant layer, it was determined to be defective [x].

(4) Water resistance 20 samples each of the same samples as the frozen dessert prepared for the easy peel test were prepared, and the lid material was sprayed with water to make dew drops for freezing. It was put in a stocker, and frozen (-30 ° C) and thawed (room temperature) were repeated every other day. After 3 weeks, it was taken out and visually inspected for any change in appearance due to water absorption of the lid material. Water resistance is good if the appearance of the lid material does not change due to water absorption in the paper layer [○]
The appearance of the lid material having irregularities due to water absorption of the paper layer or delamination, etc., is indicated by a symbol in Table 1 as poor water resistance [x].

[0039]

[Table 1] (Evaluation results)

As is clear from the evaluation results shown in Table 1, in the heat-sealing lid material of Comparative Example 1, since the coating amount of the adhesive used for laminating the base sheet was slightly insufficient, the paper layer was reinforced. The effect was not sufficient, and heat expansion at a high temperature (270 ° C.) caused a small amount of expansion, which was inferior to the expansion resistance of the heat-sealing lid material of the example. In the heat-sealing lid material of Comparative Example 2, the base paper is changed to high-quality paper,
At the same time that the strength of the paper layer is slightly reduced, the amount of the adhesive used for laminating the base material sheets is slightly insufficient as in Comparative Example 1, so that the paper layer is not sufficiently reinforced and the fire resistance is increased. The sex was even worse. And the heat-sealing lid material of Comparative Example 3 is
The PET film of the outermost layer is removed from the structure of the lid material of Example 2, and the pattern is printed on the paper surface. Therefore, the outermost layer of the lid material is a paper layer except the printed pattern layer, which is easily affected by moisture, and is inferior in curling and water resistance. On the other hand, the heat-sealing lid materials of Examples 1 and 2 have a high strength of the base paper itself, and both sides of the PET film are excellent in water resistance, heat resistance, dimensional stability, mechanical strength and the like. Are laminated with adhesive, and the amount of adhesive applied is large,
Since the reinforcing effect can be obtained by permeating the adhesive into the paper layer,
There was little curl, and it was excellent in heat expansion resistance, easy peeling and water resistance due to high temperature sealing.

[0041]

As described above in detail, according to the present invention, since metal such as aluminum foil is not used as a constituent material of the lid member, foreign matter inspection by a metal detector can be performed in product inspection after filling and sealing. It is possible, and even if it is used as a leaf-shaped lid material punched out one by one, it has no curl and has good mechanical suitability for an automatic filling / sealing machine, and
It has the effect of easily providing a heat-sealing lid material that is excellent in performance such as water resistance, heat swelling resistance in high-temperature seal, and easy peeling property, and is also excellent in discardability such as incineration after use.

[Brief description of 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]

 1 Paper 2a, 2b Biaxially stretched plastic film 3 Pattern printing layer 4a, 4b Adhesive 5 Polyolefin resin layer 6 Hot melt layer 7 Adhesive layer 8 Easy peeling resin layer

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location B29L 9:00

Claims (4)

[Claims] 1. A base sheet obtained by laminating biaxially stretched plastic films on both sides of a paper via an adhesive, and an easy peelable resin layer or an adhesive layer made of a polyolefin resin on one side of the base sheet. A heat-sealing lid material characterized in that any one of the hot-melt layers is provided. 2. The heat-sealing property according to claim 1, wherein the amount of adhesive used for laminating the base sheet is 4.0 to 10.0 g / m ² in terms of solid content on both sides. Lid material. 3. The heat-sealing lid material according to claim 1, wherein in the heat-sealing lid material, at least the outermost biaxially stretched plastic film has an antistatic property. 4. The heat-sealing lid material according to claim 1, wherein the heat-sealing lid material is in the form of a sheet that is punched into a predetermined shape in advance.