JP5793936B2 - Heat-sealable film and method for producing the same - Google Patents

Description

  The present invention relates to a packaging material used for packaging foods, beverages, pharmaceuticals, cosmetics, chemicals, and the like, in particular, a packaging material excellent in non-adhesiveness of contents. Specifically, container cover materials such as yogurt, jelly, pudding, syrup, packaging materials for retort foods such as porridge and soup, liquid containers such as chemicals and pharmaceuticals, films for storage containers such as semi-solid and gel substances The present invention relates to a heat-sealable film that can improve the removability by reducing the residual amount after take-out due to adhesion of contents by imparting water repellency to a sealant layer.

  A wide variety of packaging materials are known in the past, but their contents are also diverse. For example, there are foods, beverages, pharmaceuticals, cosmetics, chemicals, and the like such as jelly confectionery, pudding, yogurt, liquid detergent, toothpaste, curry roux, syrup, petrolatum, face wash cream, face wash mousse and the like. In addition, the contents have various properties such as solid, semi-solid, liquid, viscous material, and gel-like material.

In packaging materials for packaging these contents, in addition to the normal sealability required, the thermal adhesiveness, light-shielding, and heat resistance required to preserve the contents depending on the contents, packaging form, application, etc. , Durability and the like are required.
Furthermore, depending on the contents, there is a problem that the contents can be easily taken out when opened. That is, there is a problem that the contents adhere to the packaging material on the inner surface of the container. If the contents stored at the time of opening use adhere to the packaging material, it becomes difficult to use up all the contents, resulting in waste.
In addition, in order to use up all the contents, the contents attached to the packaging material must be collected separately, which is troublesome. For this reason, it is important that the packaging material has a property (non-adhesiveness) that prevents the contents from adhering to the packaging material in addition to the storage suitability such as the sealing property as described above.

Conventional sealant materials and lid materials that have been used for conventional packaging containers are difficult to take out because the contents adhere to the inside when opened, often causing waste of the contents and surrounding dirt.
As a method for imparting non-adhesiveness, a method of adding a water-repellent component such as a fluorine compound or silicone to the sealant layer is conceivable. However, it is difficult to ensure sealability at the time of heat sealing and to maintain the sealing strength. It has been difficult to use as a packaging material for containers such as pouches.

On the other hand, in a lid provided with a base material layer integrated with an adhesive layer and a heat seal layer, the heat seal layer has, as an additive, a glycerate ester or polyglycerin fatty acid ester having an adhesion preventing effect. , Pentaerythritol fatty acid ester, polyoxypropylene / polyoxyethylene block polymer, sorbitan fatty acid ester, polyoxyethylene alkyl ether, fatty acid amide, and other polyolefins, the thickness of which is greater than 10 μm, the adhesive layer and the heat seal There has been proposed a filler adhesion preventing lid material in which an intermediate layer made of polyolefin is provided between the layers (Patent Document 1).
However, in the lid material as described above, the type or thickness of the heat seal layer that can be used is limited, and the amount of additive such as glycerate must be strictly controlled. When the amount of the additive used is too large, the heat sealing performance is lowered. On the other hand, when the amount of the additive used is reduced, the adhesion preventing effect is lowered accordingly. In this respect, there is room for further improvement in promoting practical use.

  On the other hand, in Patent Document 6, as a packaging material capable of continuously exhibiting excellent non-adhesiveness while maintaining good thermal adhesiveness, a lid made of a laminate having at least a base material layer and a thermal adhesive layer The thermal adhesive layer is laminated as the outermost layer on one surface of the lid, and the thermal adhesive layer is hydrophobic with an average primary particle diameter of 3 to 100 nm on the outermost surface not adjacent to the other layer. A lid material has been proposed in which oxide fine particles are adhered and hydrophobic oxide fine particles form a porous layer having a three-dimensional network structure.

  According to this method, it is only necessary to apply hydrophobic oxide fine particles to the thermal bonding layer, so there is no need to control the blending of additives into the raw materials constituting the thermal bonding layer, and therefore the blending ratio is controlled. It is said that it is advantageous in terms of production efficiency, cost, etc., because the porous layer composed of a three-dimensional network structure formed by hydrophobic oxide fine particles has no mutual adhesion between the fine particles. I had the problem of being unstable.

  On the other hand, silicone oil is widely used as a material for imparting water repellency to the surface of a solid article made of metal, ceramic, plastic, or fiber. For example, amino-modified silicone oil-based water repellents are commercially available for coating automobile bodies, but coatings obtained by spraying them have low water repellency and are not sufficiently durable. Therefore, attempts have been made to further improve the water repellency of silicone oil by mixing inorganic or organic fine particles in the silicone oil.

  For example, Patent Document 2 discloses a water-repellent coating comprising a resin solution having a water contact angle of 90 degrees or more on the surface of the coating film and inorganic or organic fine particles that can impart fine irregularities to the surface after the coating film is cured. In a heat exchanger coated with this composition, a proposal has been made to reduce the obstruction of the air flow caused by water droplets by dropping even fine water droplets with a diameter of about 1 mm from the fin surface, thereby preventing efficiency reduction. Yes.

Further, in Patent Document 3, at least for the purpose of providing a film that can be applied to various substrates, has a stable water repellency, and an excellent water repellency similar to a water droplet rolling on the surface of a so-called lotus leaf. The surface is composed of fine particles having a hydrophobic particle diameter of 1 nm to 1 mm and a resin coating film, and the fine particles are exposed and fixed in an area of 20% or more of the surface area of the resin coating film. There have been proposed coatings made of fine particles made of a base material having a contact angle with water of 90 ° or more, or hydrophobic silica fine particles having a lower alkyl group on the surface.
In Patent Document 3, when the average particle size of the fine particles is reduced, the effect of the surface irregularity shape of the coating is reduced and the contact angle is reduced. When the average particle size is increased, the water repellency with respect to fine water droplets is reduced, and therefore limited to 1 nm to 1 mm. It is stated that it will be.

Further, Patent Document 4 states that “a water-repellent coating that can have a water contact angle of 150 ° or more when formed on a surface made of a material having a water contact angle of less than 120 °. And comprising a layer containing an adhesive water-repellent polymer formed on the surface and water-repellent silica particles fixed to the surface of the layer containing the adhesive water-repellent polymer. The contact angle of water on the surface of the layer itself comprising the water-repellent polymer having the adhesive property is 120 ° or less, and the average particle diameter of the water-repellent silica particles is in the range of 0.1 to 100 μm. The surface density of the water-repellent silica particles fixed to the surface in accordance with the above is selected in the range of 10 ² to 10 ⁸ particles / mm ^2. The resulting water repellent coating has a contact angle of 15 The adhesive water-repellent polymer constituting the layer containing the adhesive water-repellent polymer functions as a binder when the water-repellent silica particles are stably fixed to the surface. It is more preferable to use the above-mentioned adhesive fluorine-containing polymer or a mixture of this adhesive fluorine-containing polymer and a viscous silicone resin.

  Furthermore, Patent Document 5 describes a surface modifier composed of gel particles having a diameter in the range of 1 nm to 1 μm and a hydrophobic polymer material, whereby a contact angle of at least 150 °, further at least It is described that a coating with a contact angle of 160 ° is formed.

However, the conventional techniques proposed in Patent Documents 2 to 5 are all aimed at improving the hydrophobicity of the coating film surface, and provide a super-water-repellent surface with a contact angle exceeding 160 °. Although it is possible, the transparency (gloss) of the coating film may not be ensured, and the stability of the surface layer is often insufficient.
When a water repellent is applied to the surface of an article, the coating film is required to be transparent and glossy so as not to impair the color and texture of the article itself. In addition, it is desired that once the water repellent coating is performed, the water repellency can be maintained for a long time without peeling from the surface of the article.

In Patent Document 7, in a water repellent containing silicone oil, fine particles, and a solvent, by adding a fine particle binder that can enhance the bonding between fine particles and / or fine particles and silicone oil, It has been found that the transparency of the coating can be ensured by increasing the strength of the agent coating film and by limiting the size of the fine particles.
However, maintaining adhesion between particles with a fine particle binder remains a problem of difficulty in controlling the amount of binder added. In the case where the coating is used as a sealant on the inner surface of the container, it is inevitable that a gap remains in the layer after heat sealing, resulting in variations in heat seal strength.

JP 2002-37310 A JP-A-3-244679 JP 7-328532 A JP 2003-54318 A JP 2003-507567 A Japanese Patent No. 4348401 Japanese Patent No. 4060333

  An object of the present invention is to provide a packaging material that can exhibit excellent non-adhesiveness with high water repellency while maintaining good thermal adhesiveness.

  As a result of intensive studies on the above problems, the present inventors have used a coating agent containing hydrophobic fine particles, a wax and a dispersion solvent, thereby filling the voids between the fine particles and enhancing the bondability between the fine particles and the wax. The present inventors have found that the strength of the water repellent coating can be enhanced and have reached the present invention.

In the invention according to claim 1 of the present invention, hydrophobic fine particles having a particle diameter of 5 nm to 1 μm, a wax, and a dispersion solvent are mixed on at least a heat seal layer of a laminate having a heat seal layer on one side of a substrate. A surface water-repellent coating layer formed by application and drying of a water-repellent coating agent is provided, and the surface water-repellent coating layer adheres so that hydrophobic fine particles are covered in an island shape or the entire surface of the wax solid content on the surface of the wax solid content. A heat-sealable film,
The surface water-repellent coating layer of the sealing film forms a structure in which hydrophobic fine particles are stacked, and the voids in the structure are filled with wax solids,
The heat-sealable film is characterized in that the hydrophobic fine particles are adhered to each other .

The invention according to claim 2 of the present invention, the wax solids content of the surface water-repellent coating layer, is heat-sealable film according to claim 1, characterized in Rukoto a polyethylene wax with a molecular weight of 100 10000 .

Invention, the heat seal according to claim 1 or 2, characterized in spherical metal oxide der Rukoto hydrophobic fine particles are trimethylsilyl treatment on the surface of the surface water-repellent coating layer according to claim 3 of the present invention It is a sex film.

In the invention according to claim 4 of the present invention, during heat sealing, the hydrophobic fine particles of the surface water-repellent coating layer are buried in the sealing component and the wax solid content in the heat sealing layer to eliminate the voids, thereby improving the sealing strength. The heat-sealable film according to any one of claims 1 to 3, wherein the heat-sealable film is not reduced .

In the invention according to claim 5 of the present invention , hydrophobic fine particles are formed in an island shape on the surface of the wax solid content or on the entire surface of the wax solid content on the heat seal layer of the laminate having a heat seal layer on at least one surface of the substrate. A surface water-repellent coating layer that adheres so as to cover and forms a structure in which the hydrophobic fine particles are stacked, and the voids of the structure are filled with wax solids and the hydrophobic fine particles are adhered to each other A method for producing a heat-sealable film provided with
A surface water-repellent coating layer is formed on the heat-sealing layer by coating and drying a water-repellent coating agent in which hydrophobic fine particles having a particle diameter of 5 nm to 1 μm, a wax, and a dispersion solvent are mixed. It is a manufacturing method of the heat-sealable film .

  According to the heat-sealable film of the present invention, hydrophobic fine particles having a particle diameter of 5 nm to 1 μm, wax, and a dispersion solvent are mixed on a heat-seal layer of a laminate having a heat-seal layer on at least one side of a substrate. A surface water-repellent coating layer formed by application and drying of a water-repellent coating agent is provided, and the surface water-repellent coating layer adheres so that hydrophobic fine particles are covered in an island shape or the entire surface of the wax solid content on the surface of the wax solid content. By doing it, it can be set as the heat-sealable film which has outstanding water repellency and milk repellency, maintaining favorable heat-sealability. When this heat-sealing film is used as a lid or a packaging material for pouches, it becomes a container that can reduce the remaining amount due to adhesion of contents to the container at the time of opening.

In addition, water-repellent coating is applied to the surface of the packaging material after application and drying by applying a water-repellent coating agent in which hydrophobic particles are dispersed in a solvent and wax. Since it is arranged on the surface of the layer so that the surface is partially or entirely covered, the surface showing high water repellency by increasing the water repellency of the hydrophobic fine particles and the apparent water repellency due to its particle size and arrangement shape. Can be realized.
In this case, when the average particle size of the hydrophobic fine particles is reduced, the effect of the uneven shape is reduced and the contact angle is reduced, and when it is increased, the water repellency with respect to fine water droplets is reduced, so the average particle size is in the range of 5 nm to 1 μm. Is preferred.

  By filling the voids of the structure of hydrophobic fine particles formed on the heat seal layer after coating and drying with a binder composed of a wax component such as polyethylene wax, the hydrophobic fine particles are not easily collapsed together. At the same time, the adhesiveness of the seal portion with the heat-sealable film substrate is improved.

  The surface water-repellent coating layer is made of polyethylene wax having a molecular weight of 100 to 10,000, the hydrophobic fine particles of the surface water-repellent coating layer are trimethylsilyl-treated spherical metal oxides on the surface, heat sealing Sometimes, the hydrophobic fine particles of the surface water-repellent coating layer are buried in the sealing component and the wax solid content in the heat-sealing layer to eliminate voids, thereby maintaining the good heat-sealing property of the water-repellent packaging material of the present invention. However, it has excellent water and milk repellency, and when used as a packaging material for lids and pouches, it increases the effect as a container that can reduce the remaining amount due to adhesion of the contents to the container at the time of opening I can do it.

As described above, according to the heat-sealable film of the present invention, it is possible to apply a water repellent coating agent in which hydrophobic fine particles are dispersed in a solvent and a wax on a heat-seal layer and to dry it with a simple method. Thus, it is possible to provide a packaging material that has a high water repellency and can exhibit excellent non-adhesiveness continuously.

The top view and cross-sectional schematic diagram of an example of the heat-sealing film of this invention The top view and cross-sectional schematic diagram of another example of the heat-sealing film of this invention Schematic cross-section of an example using the heat-sealable film of the present invention as a lid material (a) Before opening (b) At opening Cross-sectional schematic diagram of an example using a conventional heat-sealable film as a lid (a) Before opening (b) At opening

An example of a typical embodiment of the heat-sealable film of the present invention will be described below with reference to the drawings as necessary.
The heat sealable film of the present invention has excellent water repellency and milk repellency while maintaining good heat sealability, and has the effect of reducing the remaining amount of contents and preventing adhesion when used as a lid or pouch. It is.

FIG. 1B shows a schematic cross-sectional view of an example of the heat-sealable film of the present invention.
The heat-sealable film (1) of the present invention has a hydrophobic particle size of 5 nm to 1 μm on the heat-seal layer (3) of the laminate (4) having the heat-seal layer (3) on one side of the substrate (2). Surface water-repellent coating layer (7) formed by applying and drying a water-repellent coating agent in which water-soluble fine particles (5), wax (6), and a dispersion solvent are mixed. Hydrophobic fine particles (5) Is attached to cover the entire surface of the wax solid content.

FIG. 2A shows a plan view of another example of the heat-sealable film of the present invention, and FIG. 2B shows a schematic cross-sectional view.
The heat sealable film (1 ′) of the present invention has a particle size of 5 nm to 1 μm on the heat seal layer (3) of the laminate (4) having the heat seal layer (3) on one side of the substrate (2). The surface water-repellent coating layer (7) formed by applying and drying a water-repellent coating agent in which the hydrophobic fine particles (5), the wax (6) and the dispersion solvent are mixed has hydrophobic fine particles (5 ) Is attached so as to cover a part of the surface of the wax solid content in an island shape.

  The heat-sealable films (1) and (1 ′) differ only in the area ratio of the wax solid content surface covered by the hydrophobic fine particles (5), and even if there is some exposed area of the wax solid content surface, it is repellent. The water effect is not significantly reduced. Hereinafter, the example shown in FIG. 1 will be described.

The surface water-repellent coating layer (7) of the heat-sealable film (1) is made of a structure in which hydrophobic fine particles (5) are stacked, and the voids of the structure are filled with a binder made of polyethylene wax. The fine particles (5) are collected and the adhesion to the heat seal layer is further improved.
More specifically, at the time of heat sealing, the hydrophobic fine particles present on the heat sealed region are embedded in the softened heat sealing layer and thus do not hinder heat sealing, but are present outside the heat sealed region. Since the hydrophobic fine particles are held on the heat seal layer as they are, their high non-adhesiveness can be exhibited.

In FIG. 3, the cross-sectional schematic diagram of the example which used the heat-sealable film of this invention as a cover material is shown. FIG. 3A shows a state before opening, and FIG. 3B shows a state when opening. The molded container (11) is filled with the contents (12) and heat sealed to the flange (14) so that the opening and the heat seal layer (3) of the heat sealable film (1) are in contact with each other. Is done. That is, the heat-sealable film of the present invention is used in a state where the hydrophobic fine particles (5) attached to the surface of the heat-seal layer (3) can come into contact with the contents (12).

Even in such a case, since the heat seal layer (3) is protected by the hydrophobic fine particles (5) and has excellent non-adhesiveness, the content (12) is not even on the surface of the heat seal layer (3). Even when contacted, the adhesion of the contents to the heat seal layer is blocked and repelled by the hydrophobic fine particles (or the wax that has penetrated into the porous layer made of the hydrophobic fine particles) (see FIG. 3A).
Therefore, the content (12) does not remain attached to the surface of the heat seal layer (3), but is repelled by the hydrophobic fine particles and returns to the inside of the container (11) (see FIG. 3B). .

  In addition, as a material of a shaping | molding container (11), it can select suitably from a metal, a synthetic resin, glass, paper, those composite materials, etc., The kind and component of a heat seal layer can be adjusted suitably according to the material. .

For comparison, FIG. 4 shows a schematic cross-sectional view of an example in which a conventional heat-sealable film is used as a lid. 4A shows a state before opening, and FIG. 4B shows a state when opening.
The molded container (11) is filled with the contents (12) and sealed in a state where the opening and the heat sealing layer (13) of the packaging material are in contact with each other. Usually, in such a case, since the heat seal layer (13) does not have the non-adhesiveness of the contents, when the contents (12) come into contact with the surface of the heat seal layer (13), the heat seal layer (13) becomes the heat seal layer of the contents. Is inevitable (see FIG. 4A).
For this reason, a part of the contents (12) is separated from the container (11) while being attached to the surface of the heat seal layer (13) and discarded (see FIG. 4B).
Thus, the heat-sealable film of the present invention can be suitably used as a container material for products in which the contents are packaged in a packaging material in a state where the contents can contact the outermost surface on the heat seal layer side. .

The substrate (2) of the heat-sealable film (1) of the present invention is not particularly limited as long as it is a film, paper, or metal foil having characteristics and processability as a packaging material.
Examples of the material of the substrate (2) include polyester resins such as polyethylene terephthalate resin (PET), polyethylene naphthalate resin (PEN), polybutylene terephthalate resin (PBT), polyethylene resin (PE), and polypropylene resin ( Polypropylene resin such as PP), polyamide resin (PA) such as nylon-6 and nylon-66, polycarbonate resin (PC), polyacrylonitrile resin (PAN), polyimide resin (PI), polyvinyl alcohol resin (PVA), polychlorinated Stretched or unstretched films such as vinylidene resin (PVDC), ethylene-vinyl alcohol copolymer resin (EVOH), nylon-6 / metaxylylenediamine nylon 6 coextruded film, polypropylene / ethylene-vinyl alcohol co Any such polymer co-extruded film can be used. Alternatively, a composite film obtained by laminating these two or more films may be used.
Metal foil such as aluminum foil and paper can be used alone or in a laminated manner. In addition, the thickness of the base material layer is usually appropriately selected within a range of 10 to 150 μm in consideration of workability.

  Examples of the heat seal layer (3) include low density polyethylene resin (LDPE), medium density polyethylene resin (MDPE), high density polyethylene resin (HDPE), linear low density polyethylene resin (L-LDPE), and polypropylene resin. (PP), ethylene-propylene copolymer (EP), ethylene-α olefin copolymer, ethylene-acrylic acid copolymer (EAA), ethylene-methacrylic acid copolymer (EMAA), ethylene-methyl acrylate copolymer Resin such as polymer (EMA), ethylene-ethyl acrylate copolymer (EEA), ethylene-methyl methacrylate copolymer (EMMA), ionomer resin, ethylene-vinyl acetate copolymer (EVA), or these Resin film, lacquer type adhesive, easy peel adhesive, It can be used an adhesive such as Ttomeruto adhesive.

  The thickness of the heat seal layer is not particularly limited, but it is usually preferably about 20 to 150 μm from the viewpoint of sealing performance, productivity, cost, and the like. In particular, in the heat-sealable film of the present invention, when heat-sealing, the gap between the hydrophobic fine particles present on the heat-sealed region is filled with the wax component, so that the thickness of the heat-seal layer is minimal. .

Examples of the method for producing the laminate (4) by laminating the base material (2) and the heat sealing layer (3) through an adhesive layer include, for example, a dry lamination method, an extrusion lamination method, and an extrusion lamination. A known method such as a sandwich lamination method using the method can be used.
As the adhesive used in the dry lamination method, generally, an adhesive for laminating such as polyurethane, polyacrylic, polyester, epoxy, polyvinyl acetate, cellulose, or the like can be used.

In the heat sealable film of the present invention, an intermediate layer may be provided between the base material (2) and the heat seal layer (3) as necessary.
When the intermediate layer is necessary, for example, gas barrier properties, mechanical toughness, flex resistance, puncture resistance, impact resistance, wear resistance, cold resistance, heat resistance, lack of chemical resistance, etc. These functions are required when it is necessary to achieve these functions required as a packaging container by providing an intermediate layer between the base material layer and the heat seal layer.
The intermediate layer further includes, for example, a printing layer, a printing protective layer (so-called OP layer), a colored layer, an adhesive layer, an adhesion reinforcing layer, a primer coat layer, an anchor coat layer, an anti-slip agent layer, a lubricant layer, and an antifogging agent layer. Etc.

In particular, when resistance to oxygen gas, water vapor, light, etc. or long-term normal temperature circulation is required, it is necessary to provide a gas barrier layer (not shown) as an intermediate layer.
For the gas barrier layer, a resin film having gas barrier properties, a gas barrier film in which a gas barrier layer is separately provided on the surface of the base film, or a metal foil such as an aluminum foil is used.
For example, ethylene-vinyl alcohol copolymer film (EVOH), polyvinyl alcohol resin film (PVA), ethylene-vinyl acetate copolymer (EVA) saponified film, polyethylene terephthalate resin (PET), polyamide resin (PA ), A film obtained by coating polyvinylidene chloride resin (PVDC) on a film such as polypropylene resin (PP), a film provided with a deposited thin film layer of an inorganic oxide such as silicon oxide or aluminum oxide, or one kind of these films A laminated film combining more than that can be used.

As the hydrophobic fine particles (5), those obtained by subjecting the surface of fine particles of metal or inorganic compound to a water repellent treatment can be preferably used. For example, silicon oxide, zinc oxide, indium oxide, magnesium oxide, aluminum oxide, titanium oxide, zirconium oxide, etc. whose surface has been subjected to trimethylsilyl treatment can be mentioned.
The hydrophobic fine particles are not particularly limited as long as they have hydrophobicity, and may be those that have been hydrophobized by surface treatment. For example, fine particles in which hydrophilic oxide fine particles are subjected to a surface treatment with a silane coupling agent or the like to make the surface state hydrophobic can also be used.

Among these, hydrophobic silica fine particles can be preferably used. In particular, hydrophobic silica fine particles having a trimethylsilyl group on the surface are preferable in that better non-adhesiveness can be obtained.
The weight of the hydrophobic fine particles contained in the water-repellent coating agent for forming the surface water-repellent coating layer (7) is not limited, but is usually preferably 0.01 to 10 g / m ² . By setting within this range, better non-adhesiveness can be obtained over a long period of time.
Hydrophobic fine particles adhering to the heat seal layer have an average primary particle diameter of 5 nm to 1 μm, so that the hydrophobic oxide fine particles are in an appropriate aggregated state, and a water-repellent substance such as wax is formed in the voids in the aggregate. As a result, excellent non-adhesiveness can be obtained. This agglomerated state is maintained on the non-sealed surface even after the heat seal layer is sealed, so that excellent non-adhesiveness can be exhibited even after the contents are sealed.

  Examples of the wax (6) contained in the surface water repellent coating layer (7) include polyethylene wax having a molecular weight of 100 to 10,000, and more preferably polyethylene wax having a molecular weight of 500 to 2000 and an average particle diameter of 1 to 5 μm.

The water-repellent coating agent for forming the surface water-repellent coating layer (7) is publicly known as roll coating, gravure coating, bar coating, doctor blade coating, kiss reverse coating, die coating, dip coating, spray coating, brush coating, etc. This method can be adopted.
When a roll coating method or the like is employed, the surface water-repellent coating layer (7) can be formed by a method of drying after forming a coating film on the heat seal layer (3) using a water-repellent coating agent.
The solvent in this case is not particularly limited. For example, organic solvents such as alcohol (ethanol), cyclohexane, toluene, acetone, IPA, propylene glycol, hexylene glycol, butyl diglycol, pentamethylene glycol, normal pentane, normal hexane, hexyl alcohol, etc. A solvent can be appropriately selected.
At this time, a dispersant, a colorant, an anti-settling agent, a viscosity modifier and the like can be used in combination.

The drying method may be either natural drying or forced drying (heat drying), but is preferably industrially forced drying. The drying temperature is not limited as long as it does not affect the thermal adhesive layer, but it is usually 150 ° C. or lower, particularly 80 to 120 ° C. in many cases.
Further, the packaging material using the heat-sealable film of the present invention may be subjected to embossing, half-cutting, notching or the like as necessary as in the case of ordinary packaging materials.

  Several embodiments of the heat-sealable film of the present invention will be described with reference to the drawings.

<Example 1>
Using a gravure printing method, printing is performed using a normal gravure ink on a corona discharge-treated surface of a 12 μm thick polyethylene terephthalate film (PET film), and a polyurethane dry laminate adhesive (weight after drying: 3.5 g) / M ² ) was used to bond a 15 μm thick aluminum foil to form a substrate.
A 30 μm linear low density polyethylene resin (LLDPE) is laminated on the aluminum surface of this base material using a polyurethane dry laminate adhesive (weight after drying: 3.5 g / m ² ), and a heat seal layer is formed on one side of the base material. A laminate having
A water-repellent coating in which 10% by weight of silicon dioxide fine particles (Nippon Aerosil; R812S primary particle diameter 7 nm) dispersed in isopropyl alcohol (IPA) and polyethylene wax (average molecular weight 800) similarly dispersed in 10% by weight of IPA are mixed. The coating agent is applied on the heat seal layer of the laminate by the gravure coating method, dried at 80 ° C. for 30 seconds and dried to form a water-repellent coat layer film having a coating amount of 3 g / m ² to produce a heat sealable film did.
Thus, a heat sealable film having a configuration of “PET / printing / adhesive layer / aluminum foil / adhesive layer / LLDPE / water-repellent coating layer” was obtained.

<Example 2>
Printing is performed on one side of a base paper with a grammage of 80 g / m ² by the gravure printing method and 12 μm on the opposite side
The PET film of m was bonded using a polyurethane-based dry laminate adhesive (weight after drying: 3.5 g / m ² ), and a hot melt adhesive (weight after drying: 30 g / m ² ) was further applied to the PET surface. A laminate having a heat sealing layer on one side of the material was prepared, and a heat sealing film was prepared in the same manner using the same water repellent coating agent as in Example 1.
As a result, a heat-sealable film having a configuration of “printing / base paper / adhesive layer / PET / hot melt / water repellent coating layer” was obtained.

<Example 3>
Water repellent in which silicon dioxide fine particles (Nippon Aerosil; R812S primary particle size 7 nm) dispersed in 10% by weight of IPA and polyethylene wax (average molecular weight 2000) similarly dispersed in 10% by weight of IPA are mixed at a weight ratio of 4: 6. A heat-sealable film was prepared in the same manner as in Example 1 except that the coating agent was used.
Thus, a heat sealable film having a configuration of “PET / printing / adhesive layer / aluminum foil / adhesive layer / LLDPE / water-repellent coating layer” was obtained.

<Comparative Example 1>
A heat-sealable film was prepared in the same manner as in Example 1 except that a heat-sealing varnish agent having 20% by weight dispersed in IPA was used instead of polyethylene wax (average molecular weight 800) dispersed in 10% by weight in IPA. .
Thus, a heat sealable film having a configuration of “PET / printing / adhesive layer / aluminum foil / adhesive layer / LLDPE / water-repellent coating layer” was obtained.

<Evaluation>
Using the above heat-sealable film, the sealing strength, contact angle and sliding angle were measured. The measurement conditions are as follows.
Seal strength: A sample was prepared by heat-sealing a heat-sealable film on a polystyrene sheet (width 15 mm). The heat seal condition was 1 second at a temperature of 210 ° C. and a pressure of 2 kg / cm ² . The sample was pulled in the direction of an angle of 180 degrees at a speed of 300 mm / min, and an average value of 6 points was obtained. The results are shown in Table 1.
Contact angle: The water repellent coating layer side of each heat-sealable film was used as a test surface, and the contact angle between pure water and milk was measured using a contact angle measuring device. The results are shown in Table 1.
Tipping angle: The water-repellent coating layer side of each heat-sealable film is used as the test surface, this surface is used as the top surface, and it is fixed with a clip on a horizontal flat table. Pure water and milk are dropped from a close range, and the horizontal flat plate is tilted. The angle when the drop fell was determined. The results are shown in Table 1. In addition, even if the fall angle of the milk of Comparative Example 1 was 90 degrees, the droplets did not slide down and flowed down, and thus expressed as adhesion.
A contact angle of 145 ° or more and a falling angle of 40 ° or less is practically sufficient, and a contact angle of 160 ° or more and a falling angle of 20 ° or less provides better water repellency (droplets do not adhere to the surface). , The property of being easy to roll off).

As is apparent from the results in Table 1, the non-adhesive property is not exhibited at all in the heat-sealable film of the comparative example, whereas the non-adhesive property is high in the heat-sealable film of the present invention of Examples 1 to 3. It can be seen that In addition, it can be seen that in terms of seal strength, it shows good performance that is practically acceptable. Moreover, it can be said from the results of the contact angle and the drop angle that the heat-sealable film of the present invention exhibits high non-adhesiveness.
As described above, the heat-sealable film of the present invention has high water repellency and milk repellency, and is a heat-sealable film that retains heat-sealability. Thus, it has been found that it is effective for use in a packaging container that can improve the removability or prevent contamination due to the adhesion of contents.

  The packaging material of the present invention is effective for various uses such as lids, pillow bags, gusset bags, self-standing bags, three-side seal bags, four-side seal bags, etc., refill containers, molded containers, packaging sheets, tubes, etc. Can be used.

DESCRIPTION OF SYMBOLS 1 ... Heat sealing film 1 '... Heat sealing film 2 ... Base material 3 ... Heat sealing layer 4 ... Laminate 5 ... Hydrophobic fine particle 6 ... Wax 7 ... Surface water-repellent coating layer 11 ... Molding container 12 ... Contents 13 ... Heat seal layer 14 ... Flange

Claims (5)

It is formed by applying and drying a water-repellent coating agent in which hydrophobic fine particles having a particle size of 5 nm to 1 μm, a wax, and a dispersion solvent are mixed on a heat seal layer of a laminate having a heat seal layer on at least one surface of a substrate. A surface water-repellent coat layer is provided, and the surface water-repellent coat layer is a heat-sealable film in which hydrophobic fine particles are adhered to the surface of the wax solid content so as to cover the entire surface of the wax solid content .
The surface water-repellent coating layer of the sealing film forms a structure in which hydrophobic fine particles are stacked, and the voids in the structure are filled with wax solids,
A heat-sealing film, wherein the hydrophobic fine particles are adhered to each other . Heat-sealable film according to claim 1 wax solid content of the surface water repellent coating layer, characterized in Rukoto a polyethylene wax with a molecular weight of 100 10,000. Heat-sealable film according to claim 1 or 2, characterized in spherical metal oxide der Rukoto hydrophobic fine particles are trimethylsilyl treatment on the surface of the surface water-repellent coating layer. The hydrophobic fine particles of the surface water-repellent coating layer are buried in the sealing component and wax solid content in the heat sealing layer to eliminate voids during heat sealing, so that the sealing strength does not decrease. Item 4. The heat-sealable film according to any one of Items 1 to 3. At least on the heat seal layer of the laminate having a heat seal layer on one side of the substrate, hydrophobic fine particles adhere to the surface of the wax solid content so as to cover the entire surface of the wax solid content. Method for producing a heat-sealable film provided with a surface water-repellent coating layer in which stacked structures are formed, and voids of the structures are filled with wax solids and the hydrophobic fine particles are adhered to each other Because
A surface water-repellent coating layer is formed on the heat-sealing layer by coating and drying a water-repellent coating agent in which hydrophobic fine particles having a particle diameter of 5 nm to 1 μm, a wax, and a dispersion solvent are mixed. A method for producing a heat-sealable film .

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