JP5929076B2 - Lid material - Google Patents

Description

  The present invention relates to a heat-sealing lid material mainly applied to containers for packaging foods, and more specifically, to prevent the adhesion of contents applied to cup containers for packaging such as yogurt, jelly, pudding, jam and mousse. The present invention relates to a lid material having an effect.

The lid member applied to the cup-shaped container is generally composed of a base film layer / aluminum foil / intermediate resin layer / sealant layer from the outside. By covering the top opening of the cup container filled with contents such as yogurt and sealing the peripheral edge to the upper edge flange of the container,
A sealed cup container is formed.

  Such a lid material is required to have heat-sealing property, sealing property, and easy peelability at the time of opening, and at the same time non-adhesiveness of the content, that is, the content hardly adheres to the back surface of the lid material. Is desired. When the contents adhere to the back surface of the lid member, there is a problem that waste due to the loss of the contents adhered to the lid member occurs or it takes time to remove the deposit. In addition, there is a problem that, when opened, the attached matter may contaminate fingers, clothing, or the surrounding area.

  In order to solve these problems, various proposals as shown in the following Patent Documents 1 to 3 have been made.

  In Patent Document 1, the innermost sealant layer is a polyolefin to which a hydrophobic additive such as a fatty acid ester or a fatty acid amide having an anti-adhesion effect is added. It is known that the amount varies greatly and is subjected to stability, and the desired performance is not sufficiently obtained.

  In Patent Document 2, an adhesion preventing layer is formed on the upper surface (inner surface side) of the sealant layer. The anti-adhesion layer contains hydrophobic inorganic oxide fine particles, and the hydrophobic inorganic oxide fine particles form a porous structure having a three-dimensional network structure to exhibit a very excellent anti-adhesion effect. However, there has been a problem that the anti-adhesion effect disappears because the hydrophobic inorganic oxide fine particles sink into the sealant layer due to a high temperature environment and a long drying time during application. In the contents filling process, particularly in the sealing process, these obstruction factors are very troublesome in terms of handling.

  In Patent Document 3, as in Patent Document 2, an adhesion preventing layer is provided on the sealant layer. By using wet silica particles having a large average particle size in the adhesion prevention layer, the precipitation of wet silica is reduced, and the adhesion prevention function can be maintained even when the high temperature environment and the drying time during application become longer. However, since the particle diameter is large, there is a problem that the particle is detached from the adhesion preventing layer. Further, there is a problem that what remains on the surface of the adhesion preventing layer causes a seal inhibition with the adherend.

JP 2002-37310 A Japanese Patent No. 4348401 Japanese Patent No. 4668352

  An object of this invention is to provide the lid | cover material which maintained the sealing performance with a to-be-adhered body, and had the adhesion preventing property of the content in view of such a background art.

  In order to solve the above-mentioned problems, the present inventors have intensively studied and have completed the present invention.

The invention according to claim 1 of the present invention is at least a lid material in which a base material layer, a metal foil layer, a sealant layer, and an adhesion preventing layer are laminated from the outside,
A plurality of irregularities are formed on the inner surface of the sealant layer,
The adhesion preventing layer is formed in the concave and convex portions of the unevenness,
The projections and depressions of the projections and depressions have a shape with a sharp tip, a shape having an R-shaped curve on the outside, and no adhesion prevention layer is formed on the projections,
The adhesion preventing layer is at least a lid material containing hydrophobic inorganic oxide fine particles and wax.

  The invention according to claim 2 of the present invention is the lid according to claim 1, wherein the adhesion preventing layer has an area covering the sealant layer of 30% or more of the surface area of the sealant layer. is there.

  The invention according to claim 3 of the present invention is such that the uneven convex portion is a polygonal cone, a cone, a hemisphere, an ellipsoid, or a combination thereof, and the pitch between the convex portions is 200 to 600 μm, The lid material according to claim 1 or 2, wherein a height from an upper end to a lower end of the convex portion is 50 to 100 µm.

  The invention according to claim 4 of the present invention is characterized in that the hydrophobic inorganic oxide fine particles are hydrophobic silica fine particles having a trimethylsilyl group on the surface thereof. It is a lid.

  The lid material according to the present invention forms an adhesion preventing layer in a plurality of concave and convex portions formed in the sealant layer, the adhesion preventing layer contains hydrophobic non-oxide fine particles and wax, and the surface area of the sealant layer By having a covering area of 30% or more, the sealing property with the adherend is maintained, and an excellent content adhesion preventing function is provided.

According to claim 1 of the present invention, at least in the lid material in which the base material layer, the metal foil layer, the sealant layer, and the adhesion preventing layer are laminated from the outside,
A plurality of irregularities are formed on the inner surface of the sealant layer,
The adhesion preventing layer is formed in the concave and convex portions of the unevenness,
The adhesion preventing layer contains at least hydrophobic inorganic oxide fine particles and wax. The adhesion preventing layer contains hydrophobic inorganic oxide fine particles having a function of preventing the adhesion of contents, and a wax that serves as a binder between the hydrophobic inorganic oxide fine particles and the sealant layer. By forming the adhesion preventing layer in the concave portion of the uneven portion on the inner surface of the sealant layer, the expression of the adhesion preventing property and the sealing property with the adherend can be maintained.

  According to a second aspect of the present invention, the area of the adhesion preventing layer covering the sealant layer is 30% or more of the surface area of the sealant layer. When the adhesion preventing layer has a coating area of 30% or more of the surface area of the sealant layer, the adhesion with the adherend can be maintained and the adhesion preventing property can be obtained.

  According to a third aspect of the present invention, the projections and depressions of the unevenness are polygonal cones, cones, hemispheres, ellipsoids, or a combination thereof, and the pitch between the projections is 200 to 600 μm, The height from the upper end of a convex part to a lower end is 50-100 micrometers. In order to form an adhesion preventing layer in the concave portion of the sealant layer, an adhesion preventing liquid is applied from above the irregularities. For this purpose, a shape in which the adhesion preventing liquid does not stay at the tip of the convex portion is good, a shape in which the tip of the convex portion is sharp, and a shape having an R-shaped curve on the outside are good. The applied anti-adhesion liquid flows into the recesses, stays, and is dried to form a film. The adhesion preventing layer is formed as a thick film. Moreover, if the pitch between convex parts is 200-600 micrometers and the length (henceforth height) from the upper end of a convex part to a lower end is the range of 50-100 micrometers, sufficient adhesion prevention effect will be expressed.

  According to claim 4 of the present invention, the hydrophobic inorganic oxide fine particles are hydrophobic silica fine particles having a trimethylsilyl group on the surface. Hydrophobic silica fine particles having a trimethylsilyl group are hydrophobic silica fine particles prepared by a dry method and have excellent adhesion preventing properties.

It is sectional drawing which shows an example of the laminated constitution of a cover material. It is explanatory drawing which shows an example of an adhesion prevention layer.

  Hereinafter, modes for carrying out the present invention will be described.

  FIG. 1 is a cross-sectional view showing an example of the layer structure of the lid member of the present invention. The lid 20 has a base material layer 1, a metal foil layer 2, an intermediate resin layer 3, a sealant layer 4, and an adhesion preventing layer 5 laminated from the outside. An adhesion preventing layer 5 for preventing adhesion of contents is formed on the innermost layer. The sealant layer has a plurality of irregularities, and the pitch between the convex portions is indicated by B, and the height of the convex portions is indicated by A.

  FIG. 2 is an explanatory view showing an example of an adhesion preventing layer. The adhesion preventing layer 5 is formed in the concave and convex concave portions 8 of the sealant layer 4 and shows a state where the hydrophobic inorganic oxide fine particles 6 are dispersed in the wax 7. When the anti-adhesion liquid is applied and dried, the drying temperature is set to be equal to or higher than the melting point of the wax 7, so that the wax 7 melts and is adsorbed to the hydrophobic inorganic oxide fine particles 6, and adheres to the sealant layer 4. This prevents the hydrophobic inorganic oxide fine particles 6 from falling off.

  In the recess 8, the adhesion preventing layer 5 is formed as a thick film. Even if part of the hydrophobic inorganic oxide fine particles 6 sinks into the sealant layer 4 during drying, the adhesion preventing function can be maintained. Further, the adhesion preventing layer is not formed on the convex portion 9. Even if it is formed thin, the wax 7 is adsorbed on the hydrophobic inorganic oxide fine particles 6 due to the drying temperature and sinks into the sealant layer 4. Since the hydrophobic inorganic oxide fine particles 6 which are concerned about seal inhibition sink, the sealing property with the adherend can be maintained. In addition, if the covering area of the anti-adhesion layer 5 is 30% or more of the surface area of the sealant layer 4, excellent anti-adhesion properties can be obtained.

  The convex part 9 of the sealant layer has a good shape in which the anti-adhesion liquid does not stay. As shown in FIG. 1, the anti-adhesion liquid can be applied by forming a pointed tip and an R-shaped curve on the outside. At this time, it flows into the concave portion without staying in the convex portion 9 and stays, and then dried to form a thick film anti-adhesion layer.

  Further, the present invention will be described in detail.

The base material layer 1 is arranged on the front side of the cover material, and is a single layer film such as polyethylene terephthalate, polyethylene, polypropylene, polyamide, polycarbonate, polyvinyl chloride, cellulose acetate, cellophane, etc., and a laminate in which these films are laminated. A film etc. can be used. Moreover, the laminated body etc. which laminated | stacked these films on paper etc. can also be used. Since it is arranged on the front side of the lid member, it is usually appropriately printed to impart design properties.

  The metal foil layer 2 is mainly used for the purpose of imparting gas barrier properties and light shielding properties, and aluminum foil is mainly used. However, a vapor deposited film on which an inorganic oxide such as silica or alumina is deposited can also be used.

  The intermediate resin layer 3 is a layer for improving the adhesiveness between the metal foil 2 and the sealant layer 4 and improving the cushioning property at the time of heat sealing and the rigidity of the lid material. Polyethylene, polypropylene, polyamide, polyethylene Films such as terephthalate, polycarbonate, and polyvinyl chloride can be used. If the thickness of a film is polyethylene, for example, 5-50 micrometers is good.

  The sealant layer 4 is required to have a sealing property with an adherend and an easy peel property. In particular, if the sealing property and the easy peel property are good, the material is not limited, but generally a hot melt agent is generally used. The hot melt agent is mainly composed of an ethylene-vinyl acetate copolymer, and a tackifier or the like is generally added as a wax or a tackifier.

  In addition to the hot melt agent, an easy peel film or the like can also be used.

  The characteristics of the easy peel are not particularly limited, and any of a cohesive peeling type and an interlayer peeling type may be used.

  The cohesive failure type is a type in which the sealant layer itself cohesively breaks. Using a resin mixed with resin such as polypropylene, polyethylene, polystyrene, etc., it is formed into a film and laminated on the intermediate resin layer, or the coating liquid of this resin is used. It can be used by coating.

  The delamination type is a method in which a three-layer film is prepared by a coextrusion method and peeled from the middle. This coextruded film can also be used.

  For example, a polygonal pyramid, a cone, a hemisphere, an ellipsoid, or a combination of these can be used as the convex and concave portions of the sealant layer 4. The unevenness is continuously formed, the pitch B between the protrusions is preferably 100 to 2000 μm, and the height A of the protrusions is preferably 10 to 300 μm, preferably the pitch is 200 to 600 μm and the height is 50 to 100 μm.

  As a method for forming a plurality of irregularities, when a sealant layer is applied and formed, a gravure coating method using a gravure plate engraved in an irregular shape, and when forming using an extruder, extrusion is performed. An extruding laminating method using a nip roll engraved with a concavo-convex shape, or a method of processing using an embossed plate as post-processing can be used.

  The adhesion preventing layer 5 contains hydrophobic inorganic oxide fine particles 6 and wax 7. The hydrophobic inorganic oxide fine particles 6 and the wax 7 are dispersed in an organic solvent to form an adhesion preventing liquid, which is applied and dried. As the organic solvent, alcohols can be used, and it is preferable to use ethanol or methanol from the viewpoint of dispersibility, handleability and price.

As the hydrophobic inorganic oxide fine particles 6, for example, at least one of silica, alumina, titania and the like can be used. Of these, hydrophobic silica particles can be preferably used. Hydrophobic silica fine particles having a trimethylsilyl group, triethylsilyl group, butyldimethylsilyl group, triisopropylsilyl group, butyldiphenylsilyl group, etc. can be used on the surface, but in particular, in that superior adhesion prevention can be obtained. Is preferably a hydrophobic silica fine particle having a trimethylsilyl group. The particle diameter of the hydrophobic silica fine particles is preferably 3 to 100 nm as the average primary particle diameter. Preferably 5-20 nm is good. Moreover, many primary particles and its aggregates (secondary particles) may be contained.

  Synthetic wax can be used as the wax. For example, waxes such as polyethylene, polypropylene, vinyl ethylene acid, and ethylene acrylic acid can be used. Polyethylene is particularly preferable. Further, it is preferable to use a wax having a wax particle diameter of 1 to 20 μm.

  Examples of the method for applying the adhesion preventing layer 5 include gravure coating, roll coating, doctor blade coating, die coating, commating, and spraying. The drying temperature is higher than the temperature (melting point) at which the wax is melted simultaneously with the drying of the organic solvent, and is preferably not higher than the melting point temperature of the resin used in the sealant layer.

  In the lid material of the present invention, the inner surface of the sealant layer is made uneven, and the adhesion preventing property is maintained by selectively forming a thick film of the adhesion preventing layer on the recess. Moreover, even if there is a portion where the sealant layer is exposed, adhesion prevention can be maintained. Moreover, since the inorganic oxide fine particles and the wax are not present on the convex portion having the largest contact with the contents, it is very excellent from the viewpoint of hygiene.

  Hereinafter, specific examples of the present invention will be described.

A 12 μm polyethylene terephthalate film and 15 μm aluminum foil as a base material layer were dry laminated using a urethane adhesive and bonded together. Furthermore, a 20 μm polyethylene film as an intermediate resin layer was extruded and laminated on the surface of the aluminum foil using the same adhesive as described above. Further, a hot melt agent (35 parts by weight of wax, 35 parts by weight of rosin, 30 parts by weight of ethylene-vinyl acetate copolymer) was gravure-coated on the polyethylene film so as to have a weight of 20 g / m ² after drying. The melting point of the hot melt agent is 110 ° C. The gravure plate used was a plate engraved in a conical convex shape. A sealant layer having irregularities was formed.

  Next, 5 g of polyethylene wax (melting point: 95 ° C.) having an average particle diameter of 7 μm and 5 g of hydrophobic silica fine particles (trade name: Aerosil R812S) having trimethylsilyl groups having an average particle diameter of 7 nm as primary particles were added as 90 g of ethyl alcohol. An anti-adhesion solution was prepared by dispersing in. This adhesion preventing liquid was gravure coated from the upper surface side of the sealant layer and then dried at 100 ° C. for 10 seconds to evaporate ethyl alcohol to form an adhesion preventing layer.

  Table 1 shows the evaluation results of adhesion prevention, adhesion, and sealability when the coating area of the formed adhesion prevention layer was changed to 25 to 87% of the surface area of the sealant layer. The pitch of the convex portions was 500 μm and the height was 90 μm.

  Table 2 shows the evaluation results of adhesion prevention, adhesion, and sealability when the height of the convex portion is changed from (0 to 5 μm) to 100 μm, and the coverage area of the adhesion prevention layer is 80 to 90%. The pitch of the convex portions was 500 μm.

Table 3 shows the evaluation results of adhesion prevention, adhesion, and sealability when the pitch of the projections is changed to 40 to 2500 μm. The coverage area of the adhesion prevention layer is 80 to 90% and the height of the projections 90 μm.

The adhesion prevention evaluation was performed as follows. The liquid used for the droplets was distilled water.
(Double-circle): The angle when a droplet begins to roll is 30 degrees or less.
○: The angle when the droplet starts to roll is 31 to 90 degrees or less.
X: Adherence of droplets is observed.

The adhesion evaluation was performed as follows.
○: Adhesion is not recognized when cellotape (registered trademark) is applied and peeled off.
X: Adhesion is recognized when cellotape (registered trademark) is applied and peeled off.

The sealing performance was evaluated as follows under the conditions of a temperature of 210 ° C., a pressure of 0.2 MPa, and a time of 3.0 seconds. Seal strength was measured with Tensilon.
○: Equivalent to the case without an adhesion preventing layer.
X: Strength reduction 30% or more.

From the evaluation results in Table 1, it was found that if the coating area of the adhesion preventing layer is 30% or more of the surface area of the sealant layer, it has adhesion preventing properties. Moreover, there was no problem also about adhesiveness and sealing performance. From the evaluation results of Table 2, if the height of the convex portion was 50 to 100 μm, the adhesion preventing property was good. There was no problem with the adhesion and sealing properties. From the evaluation results in Table 3,
When the pitch of the convex portions was 200 to 800 μm, the adhesion preventing property was good. There was no problem with the adhesion and sealing properties.

  The device of the present invention can be used for packaging bags such as pillow bags and standing pouches, molded containers such as cups and tray containers, and molded containers such as injections and tubes, in addition to lids.

DESCRIPTION OF SYMBOLS 1 Base material layer 2 Metal foil layer 3 Intermediate resin layer 4 Sealant layer 5 Adhesion prevention layer 6 Hydrophobic inorganic oxide fine particle 7 Wax 8 Concave part 9 Convex part 20 Lid material A Height B Pitch

Claims (4)

At least in the cover material laminated with the base material layer, metal foil layer, sealant layer, adhesion preventing layer from the outside,
A plurality of irregularities are formed on the inner surface of the sealant layer,
The adhesion preventing layer is formed in the concave and convex portions of the unevenness,
The projections and depressions of the projections and depressions have a shape with a sharp tip, a shape having an R-shaped curve on the outside, and no adhesion prevention layer is formed on the projections,
The lid material characterized in that the adhesion preventing layer contains at least hydrophobic inorganic oxide fine particles and wax.   The lid material according to claim 1, wherein an area of the adhesion preventing layer covering the sealant layer is 30% or more of a surface area of the sealant layer.   The projections and depressions of the unevenness are polygonal cones, cones, hemispheres, ellipsoids, or a combination thereof, the pitch between the projections is 200 to 600 μm, and the height from the upper end to the lower end of the projections The cover material according to claim 1 or 2, wherein the thickness is 50 to 100 µm.   The lid material according to any one of claims 1 to 3, wherein the hydrophobic inorganic oxide fine particles are hydrophobic silica fine particles having a trimethylsilyl group on a surface thereof.