JP6948187B2 - Contents adhesion prevention lid material - Google Patents

Description

The present invention is mainly applied to a heat-sealing lid material applied to a container for packaging foods, and more specifically, a cup-shaped container for packaging yogurt, jelly, pudding, jam, coffee beverage (cafe latte, etc.) and the like. Regarding the lid material having the property of preventing the adhesion of the applied contents.

In addition, within the scope of this specification and claims, with respect to each layer constituting the content adhesion prevention lid material, the "inner surface" faces the inside of the container body when the lid material of the present invention is applied to the container body. It means a side surface, and the "outer surface" means a surface opposite to the inner surface.

This type of heat-sealing lid material is generally a heat-sealing layer, that is, a heat-sealing layer on the aluminum foil side of a base material layer composed of a laminate of a base film and an aluminum foil, via an intermediate resin layer if necessary. The sealed package is provided by covering the upper surface opening of the cup-shaped container body filled with the packaged object such as yogurt and heat-sealing the peripheral edge portion onto the upper edge flange portion of the container body. It is supposed to form.

Therefore, in such a lid material, good heat-sealing property, sealing property, and appropriate easy peeling property for opening are required, and at the same time, the contents are non-adhesive, that is, the inner surface of the lid material on the inner side of the container. It is desired that the contents can be prevented from adhering to the cloth. If the contents adhere to the inner surface of the lid material, there is a risk that the fingers, clothes, or the surroundings will be soiled when the package is opened, and waste will occur due to damage to the contents, or it will take time and effort to remove the deposits, and further, a feeling of filth will be felt. This is because it causes disadvantages such as holding.

In response to such a request, conventionally, as a lid material having a content adhesion prevention performance, a lid material having at least a base material layer and a heat sealing layer has an adhesion prevention layer on the inner surface of the heat sealing layer. There is known a content adhesion prevention lid material in which the adhesion prevention layer is composed of hydrophobic wet silica particles having an average particle size of 0.5 to 7.0 μm, which imparts hydrophobicity to the wet silica particles (see Patent Document 1). According to this conventional technique, the content adhesion prevention performance can be obtained by providing the adhesion prevention layer made of hydrophobic wet silica fine particles on the inner surface of the heat sealing layer.

Japanese Unexamined Patent Publication No. 2012-17116

However, if the contents often come into contact with the inner surface of the lid material repeatedly due to shaking during transportation of the container, hydrophobic fine particles are likely to fall off, and especially when the contents are highly viscous contents, the contents are hydrophobic. There was a problem that the sex fine particles were more likely to fall off. If the hydrophobic fine particles fall off in this way, the performance of preventing the contents of the lid material from adhering to the contents deteriorates.

The present invention has been made in view of such a technical background, and even if the contents repeatedly come into contact with the inner surface of the lid material due to shaking during transportation or the like, the hydrophobic fine particles of the adhesion prevention layer are unlikely to fall off. An object of the present invention is to provide a content adhesion prevention lid material capable of maintaining sufficient content adhesion prevention performance.

In order to achieve the above object, the present invention provides the following means.

[1] In a lid material having at least a base material layer and a heat-sealing layer,
A coat layer is laminated on the inner surface of the heat-sealing layer, and a content adhesion prevention layer containing hydrophobic fine particles as a main component is further laminated on the inner surface of the coat layer.
The coating layer is a cover material for preventing adhesion of contents, which is a layer composed of a thermosetting product of a resin composition containing a resin component in which a plurality of resin acids are ester-bonded and a wax component.

[2] The content adhesion prevention lid material according to item 1 above, wherein the resin composition is an alcohol-soluble resin composition.

[3] The content adhesion prevention lid material according to item 1 or 2 above, wherein the resin component is a resin in which a linear resin acid and a sesquiterpene resin acid are ester-bonded.

[4] The content-adhesion-preventing lid material according to item 3 above, wherein the linear resin acid is aleuritic acid.

[5] The content adhesion prevention lid material according to the above item 3 or 4, wherein the sesquiterpene-based resin acid is at least one resin acid selected from the group consisting of shelophosphoric acid, jalaric acid and laxillaric acid.

[6] The wax component is one or two selected from the group consisting of tacardiacerol, laxerol, milliserial coal, ceryl alcohol, lignoceric acid, serott acid, stearic acid, palmitic acid and each of these esters. The content adhesion prevention lid material according to any one of the above items 1 to 5, which is the wax component.

[7] The content adhesion prevention lid material according to any one of items 1 to 6 above, wherein the thickness of the coat layer is 0.5 μm to 5 μm.

[8] In the hydrophobic fine particles constituting the content adhesion prevention layer, a part of the coat layer side is impregnated with the coat layer and a part of the side opposite to the coat layer side is exposed. The content adhesion prevention lid material according to any one of the above items 1 to 7.

[9] The content adhesion prevention lid material according to any one of items 1 to 8 above, wherein the inner surface of the heat sealing layer is a smooth surface.

[10] The hydrophobic particles have an average particle size of hydrophobic wet silica fine particles is 100Nm～5000nm, the amount of hydrophobic wet silica fine particles is 0.3g / m ² ~3.0g / m ² The content adhesion prevention lid material according to any one of the above items 1 to 9.

In the invention of [1], a coat layer is laminated on the inner surface of the heat-sealing layer, and a content adhesion prevention layer containing hydrophobic fine particles as a main component is laminated on the inner surface of the coat layer, and the coat layer is a plurality of resins. It is a structure formed by a thermocured product layer of a resin composition containing a resin component in which an acid is ester-bonded and a wax component, and since a coat layer having such a specific structure exists, the content is covered. Even if it repeatedly comes into contact with the inner surface of the material, it is possible to sufficiently prevent the hydrophobic fine particles from falling off, to secure sufficient performance to prevent adhesion of contents, and to secure good heat-sealing property.

In the invention of [2], when the hydrophobic fine particles are applied for laminating the content adhesion prevention layer, the hydrophobic fine particles can be sufficiently fixed to the coat layer, and the hydrophobic fine particles can be more sufficiently prevented from falling off. can.

In the invention of [3], it is possible to more sufficiently prevent the hydrophobic fine particles from falling off.

In the invention of [4], it is possible to more sufficiently prevent the hydrophobic fine particles from falling off.

In the invention of [5], it is possible to further sufficiently prevent the hydrophobic fine particles from falling off.

The invention of [6] has an advantage that the hydrophobic effect of the content adhesion prevention layer can be further enhanced.

In the invention of [7], when the thickness of the coat layer is 0.5 μm or more, the hydrophobic fine particles can be sufficiently prevented from falling off, and when the thickness of the coat layer is 5 μm or less, sufficient heat sealing property is obtained. Can be secured.

In the invention of [8], since the hydrophobic fine particles are partially impregnated on the coat layer side, the hydrophobic fine particles can be more sufficiently prevented from falling off, and the hydrophobic fine particles are on the coat layer side. Since a part on the opposite side is exposed, sufficient content adhesion prevention performance can be ensured.

In the invention of [9], since the inner surface of the heat-sealing layer (the surface on which the coat layers are laminated) is a smooth surface, it is possible to uniformly apply and laminate a thin coat layer, for example, having a thickness of 0.5 μm to 5 μm. The coat layer can be formed uniformly and easily.

In the invention of [10], the content adhesion prevention performance can be further improved.

It is sectional drawing which shows one Embodiment of the content adhesion prevention lid material which concerns on this invention. FIG. 5 is an enlarged schematic cross-sectional view schematically showing an enlarged view of the heat sealing layer, the coat layer, and the content adhesion prevention layer in FIG. 1.

FIG. 1 shows an embodiment of the content adhesion prevention lid material 20 according to the present invention. The content adhesion prevention lid material 20 is a base material layer 1 composed of a laminate of a base material film layer 2 and a metal foil layer 3, and an inner surface (unlaminated surface; heat) of the metal foil layer 3 of the base material layer 1. A heat-sealing layer 5 laminated via an intermediate resin layer 4 is provided on a surface of the container body facing the inside when the lid material is applied to the container body by sealing. Further, a coat layer 9 laminated on the inner surface of the heat-sealing layer 5 (a surface facing the inside of the container body when the lid material is applied to the container body by heat sealing), and a further inner surface of the coat layer 9. It is further provided with a content adhesion prevention layer 6 laminated on the surface. The content adhesion prevention layer 6 is a layer containing hydrophobic fine particles S as a main component. Further, the coat layer 9 is a layer composed of a thermosetting product of a resin composition containing a resin component in which a plurality of resin acids are ester-bonded and a wax component.

In the present embodiment, as shown in FIG. 2, an impregnated layer 11 is formed in which a part of the hydrophobic fine particles S constituting the content adhesion prevention layer 6 on the coat layer 9 side is impregnated with the coat layer 9. At the same time, a part of the hydrophobic fine particles S opposite to the coat layer 9 side (that is, the inner surface side) is exposed to form the content adhesion prevention layer 6. Therefore, the coat layer 9 includes the impregnated layer 11 on the inner surface side and the non-impregnated layer (layer not impregnated with the hydrophobic fine particles S) 12 on the outer surface side (base material layer side). Further, in the present embodiment, the inner surface of the heat-sealing layer 5 (the surface on which the coat layers are laminated) is a smooth surface, so that the resin composition for forming the coat layer can be applied thinly and uniformly. Therefore, a thin and uniform coat layer 9 is formed. Further, in the present embodiment, the surface of the base film layer 2 on the metal foil layer 3 side is printed 7 to impart designability.

The content adhesion prevention lid material 20 having the above configuration has a content adhesion prevention layer 6 containing hydrophobic fine particles S as a main component on the inner surface side, which is the side that comes into contact with the content of food or the like. Adhesion prevention performance can be obtained. Further, since the coat layer 9 having the specific configuration is present between the heat sealing layer 5 and the content adhesion prevention layer 6, even if the content repeatedly contacts the inner surface of the lid material 20, the hydrophobic fine particles S It is possible to sufficiently prevent falling off, ensure sufficient content adhesion prevention performance, and at the same time ensure good heat sealability.

In the present invention, the base film layer 2 is arranged on the front side (outer surface side) of the packaging container, and the materials thereof include polyester, polyethylene, polypropylene, polyamide, polyacrylate, polycarbonate, polyvinyl chloride, and the like. Examples thereof include a single-layer or composite film such as cellulose acetate and cellophane, or a film or resin laminated or coated on paper or the like.

The metal foil layer 3 imparts gas barrier property, light-shielding property, and the like, and an aluminum foil is preferably used, but the metal foil layer 3 is not particularly limited thereto. In the lid material 20 for a yogurt container, an aluminum foil having a thickness of 5 μm to 50 μm is preferably used in order to satisfy light-shielding property and light weight. Further, a general adhesive is used for the laminated adhesion with the base film layer 2.

As the base material layer 1, it is also possible to use a metal-deposited film in which a metal oxide such as silica or alumina, an inorganic oxide, or the like is vapor-deposited on the base film 2 without using a metal foil. ..

The intermediate resin layer 4 is interposed between the base material layer 1 and the heat sealing layer 5 to impart a predetermined rigidity and cushioning property at the time of heat sealing to the lid material, and is provided as necessary. Be done. Generally, from olefin resins such as polyethylene, polypropylene, ethylene (meth) acrylic acid copolymer, ethylene (meth) acrylic acid ester copolymer, and resins such as polyamide, polyester, polycarbonate, and polyvinyl chloride. A film having a thickness of 5 μm to 40 μm is used.

The material of the heat-sealing layer 5 is not particularly limited as long as it has good adhesiveness to the container side. for example,
(A) Hot melt resin (hot melt adhesive)
(B) A lacquer-type heat-sealing agent in which a resin or resin composition is dissolved or dispersed in a solvent (C) A heat-sealing material made of a resin or a film of the resin composition can be used.

The hot melt resin type material is not particularly limited, and examples thereof include polyolefin resin (polyethylene resin and the like), polyamide, polyester, EVA resin, synthetic rubber (styrene rubber and the like), acrylic resin and the like. Be done.

The lacquer-type heat sealant (B) is not particularly limited, and examples thereof include a composition containing a resin component (EVA resin, polyolefin, etc.), a wax component, and the like.

The heat-sealing material (C) made of the film is not particularly limited, and examples thereof include a polyethylene film, a crystalline polypropylene film, and a vinyl chloride resin film.

The thickness of the heat-sealing layer 5 is not particularly limited, but is generally set to a thickness of 3 μm to 100 μm from the viewpoint of cost, sealing property, productivity, etc., and among them, 10 μm to 50 μm. It is preferably in the range.

The coat layer 9 is a layer composed of a thermosetting product (thermosetting product of the resin composition) of the resin composition containing a resin component in which a plurality of resin acids are ester-bonded and a wax component. The resin composition is preferably an alcohol-soluble resin composition, and in this case, the coat layer 9 can be easily formed (laminated).

The resin component is preferably a resin in which a linear resin acid and a sesquiterpene resin acid are ester-bonded. The linear resin acid is not particularly limited, but aleuritic acid is preferably used. The sesquiterpene-based resin is not particularly limited, but it is preferable to use at least one resin acid selected from the group consisting of shelophosphoric acid, jalaric acid and laxillaric acid.

The wax component is not particularly limited, but is from the group consisting of tacardiacerol, laxerol, milliserial call, ceryl alcohol, lignoceric acid, serot acid, stearic acid, palmitic acid and each of these esters. It is preferable to use one or more selected waxes.

The coat layer 9 is a thermocured product layer of a resin composition containing a resin component in which a plurality of resin acids are ester-bonded and a wax component, but shellac is assumed to contain both the resin component and the wax component. Examples thereof include resin, and the coat layer 9 is preferably formed of a heat-cured product layer of shellac resin. Since the shellac resin has excellent adhesion, it is possible to more sufficiently prevent the hydrophobic fine particles from falling off.

The shellac resin is also simply referred to as "shellac" or sometimes referred to as "shellac resin". The shellac resin is a natural resin obtained from an insect (such as an insect belonging to the scale insect family such as the scale insect) (for example, a natural resin obtained by purifying the secretion of the insect).

The commercially available shellac resin is not particularly limited, and examples thereof include shellac resin manufactured by Osaka Printing Ink Mfg. Co., Ltd. The shellac resin manufactured by Osaka Printing Ink Mfg. Co., Ltd.
i) A resin in which aleuritic acid is ester-bonded to at least one resin acid selected from the group consisting of shelophosphoric acid, jalaric acid and laxillaric acid.
ii) At least one wax component selected from the group consisting of tacardiacerol, laxerol, millicereal coal, ceryl alcohol, lignoceric acid, cerot acid, stearic acid, palmitic acid and each of these esters.
iii) Dye component Contains the resin component of i) above, the wax component of ii) above, and the dye component of iii) above.

The thickness of the coat layer 9 is preferably 0.5 μm to 5 μm. When the thickness of the coat layer 9 is 0.5 μm or more, the hydrophobic fine particles can be sufficiently prevented from falling off, and when the thickness of the coat layer 9 is 5 μm or less, sufficient heat sealability can be ensured. Above all, the thickness of the coat layer 9 is particularly preferably 1 μm to 2 μm.

The resin composition (thermosetting product) of the coat layer 9 may contain additives such as dye components as long as the effects of the present invention are not impaired. The pigment component is not particularly limited, and examples thereof include laxeric acid, tacardia serinic acid, erythrolaxin, and desoxyerythroluxin. Further, since it is preferable that the inner surface of the coat layer 9 has fine irregularities from the viewpoint of further enhancing water repellency by reducing the contact area with the contents, the resin composition of the coat layer 9 (thermosetting). In the material), inorganic particles (talc particles, etc.), resin beads, and other concavo-convex particles may be contained.

For the formation of the coat layer 9, for example, a resin composition containing a resin component in which a plurality of resin acids are ester-bonded and a wax component is prepared, and this is applied to the surface (inner surface) of the heat-sealing layer 5. After that, it can be carried out by heating and thermosetting. The method for applying the resin composition is not particularly limited, and examples thereof include a gravure coating method, a spraying method, and a bar coating method. The heating temperature for the thermosetting is preferably set to 100 ° C. to 160 ° C. The heating time for the thermosetting is preferably set to 5 seconds to 120 seconds.

The content adhesion prevention layer 6 is a layer containing hydrophobic fine particles S as a main component. Here, the main component means that the content of the hydrophobic fine particles in the content adhesion prevention layer 6 is 50% by mass to 100% by mass.

The hydrophobic fine particles constituting the content adhesion prevention layer 6 are not particularly limited, but for example, hydrophobic silica fine particles, alumina fine particles, calcium oxide fine particles, calcium carbonate fine particles, calcium sulfate fine particles, calcium silicate. Examples thereof include hydrophobic inorganic fine particles such as fine particles. Above all, as the hydrophobic fine particles, it is preferable to use hydrophobic wet silica fine particles, and in this case, the content adhesion prevention performance can be further improved. Among them, more preferably used hydrophobic wet silica fine particles having an average particle size of 100Nm～5000nm, also adhered amount of the hydrophobic wet silica fine particles is 0.3g / m ² ~3.0g / m ² preferably is more preferably ^{0.5g / m 2 ~1.2g / m 2} .

The content adhesion prevention layer 6 can be formed, for example, by preparing a dispersion liquid in which hydrophobic fine particles are dispersed in a solvent and applying the dispersion liquid to the surface (inner surface) of the coat layer 9. As the solvent used for preparing the dispersion liquid, it is preferable to use an organic solvent in order to secure the fixability and adhesion of the hydrophobic fine particles to the underlying coat layer 9. Above all, it is more preferable to use an organic solvent having a polar group. Of these, the use of alcohols is particularly preferable, and the use of ethanol or methanol is most preferable from the viewpoints of cost, safety, and the effect of preventing hydrophobic fine particles from falling off.

The dispersion concentration of the hydrophobic fine particles in the dispersion liquid can be arbitrarily set in consideration of the relationship with the coating amount of the fine particles, but is preferably set to 2% by mass to 10% by mass. When it is 2% by mass or more, a sufficient amount of hydrophobic fine particles can be uniformly applied, and when it is 10% by mass or less, an excessive amount can be prevented from being applied. Above all, the concentration of the hydrophobic fine particles in the dispersion is more preferably set to 3% by mass to 6% by mass.

The method for applying the dispersion liquid is not particularly limited, and examples thereof include a gravure coating method, a spraying method, and a bar coating method.

Next, specific examples of the present invention will be described, but the present invention is not particularly limited to those of these examples.

<Example 1>
A polyethylene terephthalate film having a thickness of 12 μm was used as the base film 2, and an aluminum foil 3 having a thickness of 30 μm was bonded to one side thereof with a polyurethane-based dry laminate adhesive to obtain a base material layer 1.

Next, a polyethylene film (intermediate resin layer) 4 having a thickness of 20 μm is laminated and bonded to the surface of the base material layer 1 on the aluminum foil 3 side using a polyurethane-based dry laminate adhesive, and then the inner surface of the intermediate resin layer 4 is laminated. A hot-melt resin is applied to (the surface opposite to the base material layer) by a gravure coating method ^{so that the coating amount is 18 g / m 2} after drying to form a heat-sealing layer 5 having a thickness of 25 μm to form a lid material main body. Was obtained (see FIG. 1). As the hot melt resin, a hot melt adhesive having a composition of 55% by weight of ethylene-vinyl acetate copolymer / 40% by weight of wax / 5% by weight of tackifier (rosin) was used.

Next, a resin composition liquid (composition of 10% by mass of shellac resin and 90% by mass of ethanol) is applied to the inner surface (the surface opposite to the base material layer) of the heat-sealing layer 5 in the lid material body by a gravure coating method. Then, the shellac resin in the resin composition liquid was thermosetting by heating and drying at 140 ° C. for 60 seconds to form a coat layer 9 having a thickness of 2 μm (see FIG. 1). As the shellac resin, ethanol is a shellac resin solution manufactured by Osaka Printing Ink Mfg. Co., Ltd. (30% by mass of shellac resin and 70% by mass of ethanol corresponding to one type (first type) of shellac resin specified in JIS K5909). It was diluted about 3 times and used. The shellac resin manufactured by Osaka Printing Ink Mfg. Co., Ltd. contains a resin component in which a plurality of resin acids are ester-bonded, a wax component, and a dye component.

Further, on the inner surface of the coat layer 9 (the surface opposite to the base material layer), a dispersion liquid obtained by dispersing hydrophobic wet silica fine particles having an average particle size of 3 μm in an ethanol solvent at a dispersion concentration of 5% by mass is gravure. By applying by the coating method and then forcibly drying, the content adhesion prevention layer 6 made of the hydrophobic wet silica fine particles is formed on the surface (inner surface) of the coat layer 9, and the content adhesion having the configuration shown in FIG. 1 is formed. A preventive lid material 20 was obtained. The amount of the hydrophobic wet silica fine particles adhered after drying was 0.8 g / m ² .

<Example 2>
The base material layer 1 was obtained in the same manner as in Example 1. Next, a polyethylene film (intermediate resin layer) 4 having a thickness of 20 μm is laminated and bonded to the surface of the base material layer 1 on the aluminum foil 3 side using a polyurethane-based dry laminate adhesive, and then the surface of the intermediate resin layer 4 is laminated. A crystalline polypropylene (CPP) film immediately after extrusion was laminated and laminated on (inner surface; that is, the surface opposite to the base material layer) to form a heat-sealing layer 5 having a thickness of 35 μm to obtain a lid material main body. (See FIG. 1).

Hereinafter, with respect to the obtained lid material main body, the content adhesion prevention lid material 20 having the configuration shown in FIG. 1 was obtained in the same manner as in Example 1.

<Example 3>
The base material layer 1 was obtained in the same manner as in Example 1. Next, an anchor coating agent (two-component reaction type polyester adhesive) is applied to the surface of the base material layer 1 on the aluminum foil 3 side at a coating amount of 0.1 g / m ² , and then the surface (inner surface) of the anchor coating is applied. ), A lacquer-type heat sealant (a lacquer-type heat-seal agent blended with 80 parts by mass of an acid-modified polyolefin, 10 parts by mass of a wax component, and 10 parts by mass of an adhesive-imparting component) is applied in an amount of 5 g / m. ^It was applied so as to be No. 2 to form a heat-sealing layer 5 having a thickness of 5 μm, and a lid material main body was obtained (see FIG. 1).

Hereinafter, with respect to the obtained lid material main body, the content adhesion prevention lid material 20 having the configuration shown in FIG. 1 was obtained in the same manner as in Example 1.

<Example 4>
A content adhesion prevention lid material 20 having the configuration shown in FIG. 1 was obtained in the same manner as in Example 1 except that the coat layer 9 having a thickness of 3 μm was formed by changing the coating amount of the resin composition.

<Example 5>
A content adhesion prevention lid material 20 having the configuration shown in FIG. 1 was obtained in the same manner as in Example 1 except that the coat layer 9 having a thickness of 4 μm was formed by changing the coating amount of the resin composition.

<Comparative example 1>
After obtaining the lid material main body in the same manner as in Example 1, hydrophobic wet silica fine particles having an average particle size of 3 μm are formed on the surface (inner surface; that is, the surface opposite to the base material layer) of the heat-sealing layer 5 in the lid material main body. Was applied to the surface (inner surface) of the heat-sealing layer 5 from the hydrophobic wet silica fine particles by applying a dispersion liquid prepared by dispersing the above in an ethanol solvent at a dispersion concentration of 5% by mass by a gravure coating method and then forcibly drying. The content adhesion prevention layer 6 was formed to obtain a content adhesion prevention lid material. That is, the content adhesion prevention lid having a structure in which the coating layer 9 is not provided in the laminated structure shown in FIG. 1 and the content adhesion prevention layer made of hydrophobic wet silica fine particles is directly laminated on the inner surface of the heat sealing layer. I got the wood.

Each content adhesion prevention lid material obtained as described above was evaluated based on the following evaluation method. The results are shown in Table 1.

<Content adhesion prevention performance evaluation method>
Aloe yogurt (trademark "Morinaga Aloe Yogurt" manufactured by Morinaga Milk Industry Co., Ltd.) was dropped as a droplet of about 1 g on the inner surface (surface of the content adhesion prevention layer 6) of the obtained content adhesion prevention lid material. When this sample was slowly tilted from a horizontal state (a state where the tilt angle was 0 degrees), the "tilt angle when the droplet began to roll" was measured and evaluated according to the following criteria.
(criterion)
"◎" ... The tilt angle when starting to roll is less than 15 degrees "○" ... The tilt angle when starting to roll is 15 degrees or more and less than 30 degrees "△" ... The tilt angle when starting to roll is 30 degrees or more and 45 degrees Less than "x" ... The tilt angle when starting to roll is 45 degrees or more.

<Evaluation method for preventing falling off of hydrophobic fine particles>
A weight (500 g) wrapped with a cloth impregnated with ethanol is placed vertically on the inner surface of the obtained content adhesion prevention lid material (the surface of the content adhesion prevention layer 6), and slowly rubbed 200 mm in length to wipe it off. Then, the amount of hydrophobic fine particles adhering to the cloth (that is, the amount of hydrophobic fine particles falling off) was measured from the mass difference before and after wiping, and evaluated based on the following criteria.
(criterion)
“○”… The amount of fine particles adhered to the cloth is less than 0.1 g “Δ”… The amount of fine particles adhered to the cloth is 0.1 g or more and less than 0.2 g “×”… Adhesion of the fine particles to the cloth The amount is 0.2 g or more.

<Heat seal performance evaluation method>
A sample obtained by cutting out the obtained content adhesion prevention lid material to a width of 15 mm is placed in a strip having a width of 15 mm cut out from the container body (paper / polyethylene container) under a sealing condition of 150 ° C. × 0.2 MPa × 1.0 sec. Heat sealed. Next, the lid material was pulled in the direction of 180 ° at a speed of 100 mm / min, and the maximum load at the time of 180 ° peeling was taken as the heat seal strength.

Then, the decrease rate or increase rate of the heat seal strength of each of the above samples is based on the following determination criteria, with the heat seal strength of the lid material as it is without the coat layer and the content adhesion prevention layer as a reference value. Evaluated.
(criterion)
“⊚”… Strength reduction or increase is less than 10% “◯”… Strength reduction is 10% or more and less than 20% “×”… Strength reduction is 20% or more.

<Evaluation method of the surface (inner surface) condition of the content adhesion prevention layer>
The surface condition of the content adhesion prevention layer was visually observed, and those having a uniform and good surface condition were designated as “◯”, and those having uneven coating and having a non-uniform surface condition were designated as “x”.

As is clear from Table 1, the content adhesion prevention lid materials of Examples 1 to 5 according to the present invention are excellent in content adhesion prevention property and are less likely to cause the hydrophobic fine particles of the adhesion prevention layer to fall off. And the heat sealability was also good.

On the other hand, in Comparative Example 1 which does not have a coat layer, the hydrophobic fine particles of the adhesion prevention layer are shed to some extent, and when the contents repeatedly come into contact with the inner surface of the lid material, the content adhesion prevention performance is sufficient. Was unsustainable.

The content adhesion prevention lid material according to the present invention is suitably used as a content adhesion prevention lid material applied to cup-shaped containers for packaging yogurt, jelly, pudding, jam, coffee beverages (cafe latte, etc.) and the like. However, the present invention is not particularly limited to these, and is widely used as a heat-sealing lid material for packaging containers for foods and the like.

1 ... Base material layer 2 ... Base film 3 ... Metal leaf 5 ... Heat sealing layer 6 ... Contents adhesion prevention layer 9 ... Coat layer 11 ... Impregnation layer 20 ... Contents adhesion prevention lid material S ... Hydrophobic fine particles

Claims (9)

In a lid material having at least a base material layer and a heat-sealing layer,
A coat layer is laminated on the inner surface of the heat-sealing layer, and a content adhesion prevention layer containing hydrophobic fine particles as a main component is further laminated on the inner surface of the coat layer.
The coating layer may, Ri layer der of a thermally cured product of the resin composition comprising a resin component in which a plurality of resin acids are ester-linked, and a wax component, a,
The hydrophobic fine particles constituting the content adhesion prevention layer are characterized in that a part of the coat layer side is impregnated with the coat layer and a part of the side opposite to the coat layer side is exposed. Cover material to prevent adhesion of contents. The content adhesion prevention lid material according to claim 1, wherein the resin composition is an alcohol-soluble resin composition. The content adhesion prevention lid material according to claim 1 or 2, wherein the resin component is a resin in which a linear resin acid and a sesquiterpene resin acid are ester-bonded. The content adhesion prevention lid material according to claim 3, wherein the linear resin acid is aleuritic acid. The content adhesion prevention lid material according to claim 3 or 4, wherein the sesquiterpene-based resin acid is at least one resin acid selected from the group consisting of shelophosphoric acid, jalaric acid and laxillaric acid. The wax component is one or more waxes selected from the group consisting of tacardiacerol, laxerol, milliserial coal, ceryl alcohol, lignoceric acid, cerot acid, stearic acid, palmitic acid and each of these esters. The content adhesion prevention lid material according to any one of claims 1 to 5, which is a component. The content adhesion prevention lid material according to any one of claims 1 to 6, wherein the thickness of the coat layer is 0.5 μm to 5 μm. The inner surface of the heat-sealing layer is a smooth surface.
The content adhesion prevention lid material according to any one of claims 1 to 7, wherein the inner surface is a surface on which the coat layers are laminated. The hydrophobic fine particles are hydrophobic wet silica fine particles having an average particle size of 100 nm to 5000 nm, and the amount of the hydrophobic wet silica fine particles is 0.3 g / m. ² ~ 3.0g / m ² The content adhesion prevention lid material according to any one of claims 1 to 8.

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