JP2014069557A - Heat sealable film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat sealable film capable of imparting stable water repellent property to a sealant layer making contact with a content of a packaging medium, so as to prevent adhesion of the content and to reduce remnant amount of the content, enabling improvement of taking-out property.SOLUTION: A heat sealable film comprises a heat seal resin layer formed at least on one side of a base material film. Spherical particles with the average particle diameter of 10 μm-50 μm are dispersed in an exposed state on a surface of the heat seal resin layer, so as to form surface ruggedness. An inorganic binder layer is formed by dispersing oxide fine particles with the average primary particle diameter of 5 nm-1 μm, on the heat seal resin layer of the heat sealable film, and then a water repellent coat layer coats thereon.

Description

The present invention relates to a material for packaging foods, beverages, pharmaceuticals, chemicals and the like.
For example, film used for storage containers for container lids such as yogurt, jelly, pudding, syrup, retort food packaging such as porridge and soup, liquids such as chemicals and pharmaceuticals, semi-solids, and gel-like substances Regarding materials.
Specifically, in the cover material of the opening container that can prevent the leakage of the contents due to the sealing failure and the erroneous opening after sealing by giving the surface irregularities coated with micron particles, while maintaining easy opening. The present invention relates to a heat-sealable film that maintains easy-openability and sufficient seal strength, and reduces adhesion of contents to make it difficult to jump out.

  Conventionally, packaging materials used for contents of various properties such as semi-solids, liquids, viscous bodies, gels, etc. other than solids are known, and the contents are 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. There are also various properties of the contents.

The packaging materials for packaging these contents are required to have hermeticity as well as thermal adhesiveness, light shielding, heat resistance, durability, etc. depending on the contents, packaging form, application, etc. The
However, even packaging materials that satisfy these characteristics have the following problems. That is, there is a problem that the contents adhere to the packaging material. If the contents 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 desirable that the packaging material has a property (non-adhesiveness) that the contents are difficult to adhere to the packaging material in addition to the above-described sealing performance.

With respect to such a problem, Patent Document 1 discloses at least a base material layer (10) and a thermal adhesive layer (11) as a packaging material capable of continuously exhibiting excellent non-adhesiveness while maintaining good thermal adhesiveness. The thermal adhesive layer is laminated as an outermost layer on one side of the packaging material, and the thermal adhesive layer is primary on the outermost surface not adjacent to the other layer. A packaging material to which hydrophobic oxide fine particles (12) having an average particle diameter of 3 to 100 nm are attached has been proposed (see FIG. 2).
However, this method of imparting water repellency using hydrophobic particles has the disadvantage that the fine particles of hydrophobic oxide are arranged in a three-dimensional network, so that the mechanical strength is weak and the hydrophobic particles are easy to peel off from the substrate. Was.

  Patent Document 2 is characterized by containing silicone oil, hydrophobic metal oxide fine particles having an average particle diameter of 5 nm to 20 nm, wax and / or paraffin as a fine particle binder, a surfactant, an aqueous solvent and water. Although a water repellent for sprays having super water repellency has been proposed, there is a limitation in terms of production efficiency in that the processing method is limited to spray.

Further, in Patent Document 3, as a heat-sealing lid material having a content adhesion preventing property, which is difficult to adhere to the contents of the filled gel food and has high adhesion to the container, heat sealing is applied to the base material. In the heat-sealing lid material laminated in order with the adhesive layer and the content adhesion preventing layer, the composition of the content adhesion preventing layer is composed of a wax and a filler dispersed in the wax. A heat-sealing lid material for packaging containers has been proposed.
However, even in this method in which the content adhesion preventing layer is composed of wax and fine particles, the water repellency may be insufficient due to insufficient surface irregularities.

Moreover, in patent document 4, as a container which can exhibit the outstanding non-adhesiveness continuously, it is a container for accommodating the content, Comprising: Primary particle | grains are in part or all of the surface where a container contacts at least the content. Non-adhesive containers with hydrophobic oxide fine particles having an average diameter of 3 to 100 nm are proposed.
However, similar to the packaging material of Patent Document 1, this container does not increase the film cohesion unless it is fixed by heat at 120 ° C. to 200 ° C. When the temperature is high, there is a problem that the sealant layer is easily melted by heat and its shape is easily changed.

In Patent Document 5, as a laminate capable of continuously exhibiting excellent water repellency and non-adhesiveness, and as a packaging material, at least part of the surface of a layer containing a thermoplastic resin has an average primary particle diameter of 3 nm to 100 nm. A laminate and a packaging material to which hydrophobic oxide fine particles are attached have been proposed. Furthermore, a laminate and a packaging material have been proposed in which filled particles containing at least one of an organic component and an inorganic component are included in the thermoplastic resin-containing layer.
However, since the method of imparting water repellency with the hydrophobic particles does not use a binder as in the method of Patent Document 1, it has a drawback that the fixing strength is weak and the hydrophobic particles are easily peeled off from the substrate. .

Japanese Patent No. 4348401 Japanese Patent No. 4060333 JP 2009-73523 A JP 2010-254377 A JP 2011-93315 A

Ordinary sealant materials and lid materials are difficult to remove due to adhesion of the contents, and often cause waste or dirt of the contents.
In addition, although fluorine materials and silicones have water repellency and adhesion prevention effects, they have poor sealing properties and are difficult to use for container packaging materials such as lids and pouches.
From the viewpoint of safety and health, halogen water repellents with low surface energy are considered to be slightly inferior in water repellency because water repellents having a C8 main chain may have a high residual rate in the body. C6 and silicone are often used, and the water repellency is somewhat inferior.
In addition, the water-repellent coating agent using hydrophobic fine particles has weak film cohesion and adhesion, and the particles are likely to be detached.
Further, in the method of coating the water repellent on the sealant, the water repellent layer is likely to cause heat seal inhibition, and there is a concern that the lid material may be peeled off during transportation, or the contents may leak due to poor sealing.

  Providing a heat-sealing film that prevents the contents from sticking and reduces the remaining after taking out by providing stable water repellency to the sealant layer in contact with the contents of the packaging material, thereby improving the take-out property This is the subject of the present invention.

In the invention according to claim 1 of the present invention, a heat sealing resin layer is formed on at least one surface of a base film, and spherical particles having an average particle diameter of 10 μm to 50 μm are dispersed in a state exposed on the surface of the heat sealing resin layer. An inorganic binder layer in which oxide fine particles having an average primary particle diameter of 5 nm to 1 μm are dispersed is formed on the heat seal resin layer of the heat sealable film having surface irregularities formed thereon, and a water repellent coating layer is formed thereon. It is a heat-sealable film characterized by being coated.

  According to a second aspect of the present invention, the spherical particles contained in the heat-sealable film are made of a plastic selected from silicone, metal oxide or polyethylene resin, polystyrene resin, polypropylene resin, polyester resin, and acrylic resin. The heat-sealable film according to claim 1.

  The invention according to claim 3 of the present invention is characterized in that the spherical particles contained in the heat-sealable film are exposed at a height of more than half of the diameter from the surface of the heat-seal resin layer. 2. The heat-sealable film according to 2.

  The invention according to claim 4 of the present invention is characterized in that the spherical particles contained in the heat-sealable film retain their shape even after heat sealing and are embedded in a substrate to be sealed. It is a heat-sealing film of any one.

  In the invention according to claim 5 of the present invention, the surface shape of the water-repellent coating layer of the heat-sealable film has fractal irregularities due to spherical particles and fine particle dispersion, and the surface roughness Rz is more than 5 μm. The heat-sealable film according to any one of claims 1 to 4, wherein

  In the invention according to claim 6 of the present invention, the water-repellent treatment of the water-repellent coating layer in the heat-sealable film is a monomolecular film mainly composed of a hydrophobic functional group containing a methyl group by a dry or wet method. The heat-sealable film according to any one of claims 1 to 5, which is provided.

  According to the heat-sealable film of the present invention, a heat-seal resin layer is formed on at least one side of the base film, and spherical particles having an average particle diameter of 10 μm to 50 μm are dispersed in a state exposed on the surface of the heat-seal resin layer. An inorganic binder layer in which oxide fine particles having an average primary particle diameter of 5 nm to 1 μm are dispersed is formed on the heat seal resin layer of the heat sealable film having surface irregularities formed thereon, and a water repellent coating layer is formed thereon. Since it has a heat seal layer that is coated, high water repellency and milk repellency are imparted in the area in contact with the contents, and heat sealability is maintained, and the contents remain as a packaging material used for the container body. It is possible to provide a cover material and a packaging material that prevent contamination due to a small amount of packaging material and content adhesion.

In addition, spherical particles appearing on the surface of the heat-sealing resin layer can give a large surface roughness, and an uneven base material having a fractal shape can be created by providing an inorganic binder layer mixed with oxide fine particles thereon. .
Furthermore, by applying a water-repellent treatment to the surface, a water-repellent surface having a low surface energy can be formed without breaking the surface shape, and a water-repellent layer is formed on a flat substrate due to the effects of surface irregularities and water-repellent treatment. The water repellency can be improved compared to the provided film.

In addition, since the spherical particles protrude from the heat sealing resin layer to the surface of 1/2 or more of the particle diameter, a steep step appears, and the water-repellent coating is performed together with the unevenness of the oxide fine particles to make the water-repellent from the flat surface. In addition, the adhesiveness with the substrate to be sealed can be improved by the anchoring effect at the time of heat sealing.
At the time of carrying out heat sealing, since the fine unevenness imparting layer using an inorganic binder is present on the particle unevenness, the inorganic layer is broken in a situation where the sealing pressure is applied, and the water repellent coating layer does not hinder the sealing, The sealing resin can easily reach the surface of the adherend, and a strong heat seal can be achieved.

Schematic sectional view showing an example of the layer structure of the heat-sealable film of the present invention Schematic cross section showing an example of the layer structure of a conventional heat-sealable film Cross-sectional schematic diagram showing an example of the layer structure of the heat-sealable film of the present invention (Example 1) Cross-sectional schematic diagram showing an example of the layer structure of the heat-sealable film of the present invention (Example 2) Cross-sectional schematic diagram showing an example of the layer structure of a conventional heat-sealable film (Comparative Example 1) Schematic cross section showing an example of the layer structure of a conventional heat-sealable film (Comparative Example 2)

Embodiments of the present invention will be described below with reference to the drawings as necessary.
FIG. 1 is a schematic cross-sectional view of an example of the heat-sealable film of the present invention. The upper part of the figure is the direction in which the lower part is the outer side and the lower part is the outer side when used in a package.

  In the invention according to claim 1 of the present invention, the heat sealing resin layer (2) is formed on at least one surface of the base film (1), and spherical particles (3) having an average particle diameter of 10 to 50 μm are heat sealing resin. An inorganic binder layer in which oxide fine particles (5) having an average primary particle diameter of 5 nm to 1 μm are dispersed on a heat-sealing resin layer of a heat-sealable film which is dispersed on the surface of the layer to form surface irregularities. A heat-sealable film (7) characterized in that (4) is formed and covered with a water-repellent coating layer (6) from above.

As a base material (1) used for the heat-sealable film of the present invention, a known material or a laminated material can be employed. For example, paper, synthetic paper, resin film, resin film with vapor deposition layer,
A simple substance such as an aluminum foil or a composite material / laminated material thereof can be suitably used.
In these materials, each layer employed in a known packaging material may be laminated at an arbitrary position. 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, an anti-fogging agent layer and the like can be mentioned.

The lamination method in the case of using a laminated material is not limited, and known methods such as a dry lamination method, an extrusion lamination method, a wet lamination method, and a heat lamination method can be employed.
Although the thickness of a base material layer is not limited, What is necessary is just to set suitably in the range of 15 micrometers-500 micrometers normally from viewpoints, such as the intensity | strength as a packaging material, a softness | flexibility, and cost.

As a material used for the heat seal resin layer (2) of the heat sealable film of the present invention, a known material can be employed. In addition to a sealant film such as an extruded polyethylene resin, a layer formed of an adhesive such as a lacquer type adhesive, an easy peel adhesive, or a hot melt adhesive can be employed. Preferably, acrylic heat seal varnish, hot melt, polyethylene resin for extrusion, and the like are used.
Although the thickness of the heat seal resin layer (2) is not particularly limited, it is usually preferably about 2 to 150 μm from the viewpoint of sealing performance, productivity, cost and the like.

As the spherical particles (3) contained in the heat sealable film (7), a plastic selected from silicone, metal oxide or polyethylene resin, polystyrene resin, polypropylene resin, polyester resin, and acrylic resin can be preferably used. .
The spherical particles (3) are exposed at a height of more than half the diameter from the surface of the heat seal layer, retain the shape after heat seal, and are embedded in the substrate to be sealed.

The hydrophobic oxide fine particles (5) of the heat-sealable film of the present invention preferably have an average primary particle size of 5 nm to 1 μm. By setting the average primary particle size in the above range, the oxide fine particles are in an appropriate aggregated state, and a gas such as air can be retained in the voids in the aggregate, resulting in excellent non-adhesiveness. Can do.
That is, this agglomerated state is maintained even after adhering to the thermal adhesive layer, so that excellent non-adhesiveness can be exhibited.

The oxide fine particles (5) are not particularly limited as long as they have hydrophobicity, and may be those 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.
The type of oxide is not limited as long as it has hydrophobicity. For example, at least one of silica (silicon dioxide), alumina, titania and the like can 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.
Examples of commercially available products corresponding to this include “AEROSIL R300” and “AEROSIL R812S” (both manufactured by Evonik Degussa).
As a binder used for an inorganic binder layer (4), the silica sol binder which consists of a tetraethoxysilane hydrolysis solution is mentioned, for example.

  As a method for applying the oxide fine particle coating agent, a known method such as roll coating, gravure coating, bar coating, kiss reverse coating, die coating, doctor blade coating, brush coating, dip coating, spray coating, spin coating or the like may be employed. I can do it.

The water-repellent coating method for the water-repellent treatment is any of dry methods such as vacuum deposition, sputtering, and CVD, and wet methods such as dipping, spraying, spin coating, brush coating, and die coating. Can be used.
By these coating methods, at least one of trimethylsilyl, dimethylsilyl, dimethylsiloxane, dimethylpolysiloxane, alkylsilyl, and methacrylsilyl is formed on the uneven surface of the inorganic binder layer (4) containing the oxide fine particles (5). It is possible to coat a single molecule without destroying the surface irregularities formed by spherical particles and fine oxide particles by attaching a hydrophobic functional group containing.

The surface shape of the water-repellent coating layer of the heat-sealable film has fractal irregularities due to spherical particles and fine particle dispersion, and the surface roughness Rz is more than 5 μm.
Further, the water repellent treatment of the water repellent coating layer is performed by providing a monomolecular film mainly composed of a hydrophobic functional group containing a methyl group by a dry method or a wet method.

In the production of the heat-sealable film of the present invention, it is assumed that the surface area is increased in order to enhance the water repellency on the surface of the heat-seal resin layer (2). A spherical particle (3) having a diameter (10 to 50 μm) that can be held by the sealing resin layer is applied to the surface of the base film as a surface irregularity imparting material.
Alternatively, a heat-sealable coating liquid in which spherical particles (3) and a heat-sealable resin are mixed is applied onto the substrate (1) and dried.

  A silica binder resin layer (4) containing oxide fine particles (5) is separately applied on these heat-sealing uneven base materials. The particle diameter of the oxide fine particles (5) is set to an average primary particle diameter (5 nm to 1 μm) that can easily fill the gaps between the spherical particles (3) and contribute to the formation of surface irregularities. Further, a water repellent coating layer (6) is applied on the surface using a silane coupling agent or various silicones.

The surface of the heat-sealable film (7) after coating and drying has a structure in which spherical particles (3) are dispersed almost uniformly and oxide fine particles (5) are adhered on the entire surface.
The average particle diameter of the spherical particles (3) has a size that is at least twice as large as the resin thickness of the heat sealing resin layer (2).

Further, the oxide fine particles (5) are dispersed in an inorganic binder layer (4) such as silica so that the fine particles (5) are firmly adhered to the spherical particles (3) and the heat seal resin layer (2). The fine particles (5) are arranged so as to cover almost the entire surface, and are firmly adhered to the substrate.
In addition, the subsequent water-repellent treatment is performed by coating on the order of a monomolecular film, thereby attaching hydrophobic functional groups to the entire surface without changing the unevenness of the substrate surface, and a heat-sealing film with high water and water repellency. It becomes possible.

Since the spherical particles (3) are larger than the heat sealing resin layer (2), the spherical particles (3) bite into the base material to be sealed at the time of heat sealing. Maintains adhesion strength and plays a role in supplementing.
In addition, since the water repellent coating layer is arranged along the surface irregularities, the water repellent coating layer is likely to be partially destroyed by the sealing pressure during heat sealing, and the lower heat sealing resin begins to ooze onto the surface to be sealed. Adhesion with the substrate can be maintained.
In this way, the heat-sealable film of the present invention has excellent water repellency while maintaining good heat-sealability, and when used as a lid or pouch, it reduces the amount of contents remaining and prevents adhesion And so on.

<Example 1>
Printing surface of a polyethylene terephthalate film (PET) with a thickness of 12 μm, on which one side of a 15 μm-thick aluminum foil (AL) is back printed using a polyurethane dry laminate adhesive (coating amount after drying: 3.5 g / m ² ) And a substrate (20) was prepared.
After applying urethane anchor coat on PET / AL base material (20) prepared by dry lamination, spherical particles with average particle diameter of 20μm made of acrylic resin and heat sealant made of acrylic resin are dispersed in ethyl acetate Then, the dispersion adjusted to a solid content of 30% by mass is applied by gravure coating so that the coating amount after drying of the heat sealant is 4.0 g / m ² , thereby providing unevenness by the spherical resin (3). A heat-sealable substrate was prepared.

Further, a silica sol binder comprising untreated silica fine particles (Nippon Aerosil R300) having an average primary particle diameter of 7 nm and a TEOS (tetraethoxysilane) hydrolyzed solution is solidified as oxide fine particles (5) on the heat-sealable substrate. The oxide fine particle coating agent, which was mixed at a weight ratio of 1: 1 and diluted to 10% by mass with methanol, was applied by gravure coating at an application amount of 1.5 g / m ² to obtain a concavity and convexity heat sealing substrate.
Furthermore, a water repellent coating agent obtained by dissolving 10% by mass of hexamethyldisiloxane in a mixed solvent of 0.01N hydrochloric acid and methanol is dip-coated on the irregularity-imparting heat seal base material to provide water-repellent heat sealability. It was set as the film (17) (refer FIG. 3).

<Example 2>
Printing surface of a polyethylene terephthalate film (PET) with a thickness of 12 μm, on which one side of a 15 μm-thick aluminum foil (AL) is back printed using a polyurethane dry laminate adhesive (coating amount after drying: 3.5 g / m ² ) And a substrate (20) was prepared.
After applying a urethane anchor coat on a PET / AL substrate (20) prepared by dry lamination, a heat sealant made of acrylic resin is dispersed in ethyl acetate and 20
The dispersion liquid adjusted to a solid content of mass% is applied by gravure coating so that the coating amount after drying becomes a coating amount of 2.0 g / m ^2. Then, a particle dispersion liquid in which spherical particles (3) having an average particle diameter of 20 μm made of acrylic resin were dispersed with ethyl acetate was uniformly applied by bar coating to prepare a heat-sealable substrate with irregularities.

Further, a silica sol binder comprising untreated silica fine particles (Nippon Aerosil R300) having an average primary particle diameter of 7 nm and a TEOS (tetraethoxysilane) hydrolyzed solution is solidified as oxide fine particles (5) on the heat-sealable substrate. The oxide fine particle coating agent, which was mixed at a weight ratio of 1: 1 and diluted to 10% by mass with methanol, was applied by gravure coating at an application amount of 1.5 g / m ² to obtain a concavity and convexity heat sealing substrate.
Furthermore, a water repellent coating agent obtained by dissolving 10% by mass of hexamethyldisiloxane in a mixed solvent of 0.01N hydrochloric acid and methanol is dip-coated on the irregularity-imparting heat seal base material to provide water-repellent heat sealability. It was set as the film (27) (refer FIG. 4).

<Comparative Example 1>
Printing surface of a polyethylene terephthalate film (PET) with a thickness of 12 μm, on which one side of a 15 μm-thick aluminum foil (AL) is back printed using a polyurethane dry laminate adhesive (coating amount after drying: 3.5 g / m ² ) And a substrate (20) was prepared.
Dispersion prepared by applying a urethane anchor coat on a PET / AL substrate (20) prepared by dry lamination and then dispersing an acrylic resin heat sealant in ethyl acetate to a solid content of 20% by mass. The liquid is applied by gravure coating so that the coating amount after drying is 2.0 g / m ^2, and is composed of hydrophobic silica fine particles and a TEOS hydrolysis solution on a base film used as a heat-sealable base material. The oxide fine particle coating agent mixed with the silica sol binder was applied by gravure coating to obtain a heat-sealable film (37) imparted with water repellency (see FIG. 5).

<Comparative example 2>
Printing surface of a polyethylene terephthalate film (PET) with a thickness of 12 μm, on which one side of a 15 μm-thick aluminum foil (AL) is back printed using a polyurethane dry laminate adhesive (coating amount after drying: 3.5 g / m ² ) And a substrate (20) was produced.
A heat sealant made of acrylic resin and spherical particles (3) having an average particle diameter of 15 μm on a base material coated with urethane anchor coat on a PET / AL base material (20) prepared by dry lamination Was dispersed in ethyl acetate to prepare a dispersion having a solid content of 30% by mass by gravure coating at a coating amount of 20.0 g / m ² , and irregularities due to the spherical resin (3) were formed on the heat seal resin layer (2 ) A heat-sealable base material having a shape almost buried in the inside was prepared.

Further, a silica sol binder comprising untreated silica fine particles (Nippon Aerosil R300) having an average primary particle diameter of 7 nm and a TEOS (tetraethoxysilane) hydrolyzed solution is solidified as oxide fine particles (5) on the heat-sealable substrate. The oxide fine particle coating agent, which was mixed at a weight ratio of 1: 1 and diluted to 10% by mass with methanol, was applied by gravure coating at an application amount of 1.5 g / m ² to obtain a concavity and convexity heat sealing substrate.
Furthermore, a water repellent coating agent obtained by dissolving 10% by mass of hexamethyldisiloxane in a mixed solvent of 0.01N hydrochloric acid and methanol is dip-coated on the irregularity-imparting heat seal base material to provide water-repellent heat sealability. It was set as the film (47) (refer FIG. 6).

<Evaluation results>
<Seal strength>
The seal strength of the samples obtained in each example and comparative example was examined.
The heat-sealable films prepared in Examples 1 and 2 and Comparative Examples 1 and 2 were heat-sealed with an impulse sealer on the flange of a flanged polystyrene container, and the seal strength was measured with a tensile tester (Tensilon). .
The heat sealing conditions were a temperature of 210 ° C. and a pressure of 2 kg / cm ^{2 for} 1.0 second, and the seal strength measurement conditions were a tensile speed of 300 mm / min, a peeling angle of 180 degrees, a seal width of 10 mm, a measurement film width of 15 mm, and n = The average value of 3 was obtained.

<Contact angle>
The content side of each film is used as a test surface, this surface is used as the top surface, and it is fixed to a horizontal flat plate with a clip. did. The contact angle between pure water and yogurt was measured using a contact angle measuring device.

<Tumble angle>
The falling angle of pure water and yogurt is the test surface on the content side of each film.Drop the water droplets and yogurt from a close distance, tilt the horizontal flatbed, and if the yogurt droplets fall down, visually determine the angle, The case where the plateau slid without falling down even if the flat table was tilted 90 degrees was regarded as the adhesion residue.

<Adhesion strength>
Adhesion strength test of the water-repellent treatment of the surface in contact with the contents of the heat-sealable film, using a Gakushin type abrasion resistance tester (JISK5701), 100 reciprocations, load 200 g, mating material: chrome-plated surface A wear resistance test was performed.
After the wear resistance test, the above-mentioned yogurt tumbling angle test was conducted. The case where the yogurt droplets fell off was rated as “◯”, and the case where adhesion did not fall off even when the flat table was tilted by 90 degrees was regarded as adhesion (failed).
The above results are shown in Tables 1 and 2.

As is clear from the results in Table 1, the heat-sealable film of the comparative example has a low sealing strength, and is particularly weak in the comparative example 2 in which spherical particles are embedded in the heat-sealable resin layer.
Regarding non-adhesiveness, there is a general difference in contact angle and sliding angle between Example and Comparative Example, which indicates that the heat-sealing film of the present invention is excellent.
In particular, when yogurt is selected as the stored item, there is an adhesion residue in the comparative example, but it can be seen that in the example, the falling angle is less than 10 ° and high non-adhesiveness is exhibited.

It can also be seen that the heat-sealable films of the examples show good performance that is practically satisfactory even in the item of adhesion strength indicating the degree of adhesion deterioration after the surface abrasion test by the Gakushin Tester.
From the above results, according to the heat-sealable film of the present invention, by providing a stable water repellency to the sealant layer in contact with the contents of the packaging material, the adhesion of the contents is prevented and the residual after removal is reduced. In addition, it has become possible to provide a heat-sealable film that can improve the take-out property.

  Such a heat-sealable film of the present invention can be used as a covering material as a packaging material, as well as a pillow bag, a gusset bag, a self-supporting bag, a three-side seal bag, a four-side seal bag, and the like, a molded container, a packaging sheet, and a tube. It can be effectively used for various applications such as.

DESCRIPTION OF SYMBOLS 1 ... Base material 2 ... Heat seal resin layer 3 ... Spherical particle 4 ... Inorganic binder layer 5 ... Fine oxide particle 6 ... Water-repellent coating layer 7 ... Heat seal film 8 ... Aluminum foil 9 ... Adhesive 10 ... Base material 11 ... Thermal adhesive layer 12 ... hydrophobic oxide fine particles 13 ... back printing 14 ... polyester film 17 ... heat sealable film 20 ... substrate 27 ... heat sealable film 37 ... heat sealable film 47 ... heat sealable film

Claims (6)

  A heat seal resin layer is formed on at least one surface of the base film, and spherical particles having an average particle diameter of 10 μm to 50 μm are dispersed in a state of being exposed on the surface of the heat seal resin layer to form surface irregularities. A heat seal characterized in that an inorganic binder layer in which oxide fine particles having an average primary particle diameter of 5 nm to 1 μm are dispersed is formed on the heat seal resin layer of the film, and is covered with a water repellent coating layer thereon. Sex film.   The spherical particles contained in the heat-sealable film are made of plastic selected from silicone, metal oxide or polyethylene resin, polystyrene resin, polypropylene resin, polyester resin, and acrylic resin. Heat sealable film.   The heat sealable film according to claim 1 or 2, wherein the spherical particles contained in the heat sealable film are exposed at a height of at least half the diameter from the surface of the heat seal resin layer.   The heat-sealable film according to any one of claims 1 to 3, wherein the spherical particles contained in the heat-sealable film retain a shape even after heat-sealing and are embedded in a substrate to be sealed. .   The surface shape of the water-repellent coating layer of the heat-sealable film has fractal irregularities due to spherical particles and fine particle dispersion, and the surface roughness Rz is more than 5 μm. The heat-sealable film according to claim 1.   The water-repellent treatment of the water-repellent coating layer in the heat-sealable film provides a monomolecular film mainly composed of a hydrophobic functional group containing a methyl group by a dry or wet method. 6. The heat sealable film according to any one of 5 above.