JP5647774B2 - Packaging materials - Google Patents

Description

  The present invention relates to a packaging material. More specifically, the present invention relates to a packaging material used for packaging foods, beverages, pharmaceuticals, cosmetics, chemicals, and the like. In particular, the present invention relates to a packaging material excellent in non-adhesiveness of contents.

  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, carrero, 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.

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, the packaging material needs to have a property (non-adhesiveness) that the contents are difficult to adhere to the packaging material in addition to the above-described sealing property and the like.

  On the other hand, in a lid provided with a base material layer and a heat seal layer integrated through an adhesive layer, the heat seal layer has an anti-adhesion effect, glyceric acid ester, polyglycerin fatty acid ester, pentaerythritol fatty acid. It is made of polyolefin containing ester, polyoxypropylene / polyoxyethylene block polymer, sorbitan fatty acid ester, polyoxyethylene alkyl ether, fatty acid amide, etc., and its thickness is thicker than 10 μm, between the adhesive layer and the heat seal layer There has been proposed a filler adhesion prevention lid material characterized in that an intermediate layer made of polyolefin is provided (Patent Document 1).

JP 2002-37310 A

  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.

  Accordingly, a main object of the present invention is to provide a packaging material capable of continuously exhibiting excellent non-adhesiveness while maintaining good thermal adhesiveness.

  As a result of intensive studies in view of the problems of the prior art, the present inventor has found that the above object can be achieved by adopting a laminate having a specific structure as a packaging material, and has completed the present invention. It was.

That is, the present invention relates to the following packaging materials.
1. A packaging material used for packaging foods, beverages, pharmaceuticals, cosmetics or chemicals, which is a packaging material comprising a laminate having at least a base material layer and a thermal adhesive layer, wherein the thermal adhesive layer is a packaging material. Hydrophobic oxide fine particles having a primary particle average diameter of 3 to 100 nm are adhered to the outermost surface, which is laminated as the outermost layer on one side, and the thermal adhesive layer is not adjacent to the other layer, and the hydrophobic oxide fine particles Is a hydrophobic silica, and the hydrophobic oxide fine particles form a porous layer having a three-dimensional network structure. Embedded in the thermal adhesive layer ,
The porous layer having the three-dimensional network structure is formed by a method in which a coating film is formed on a thermal adhesive layer using a dispersion obtained by dispersing hydrophobic oxide fine particles in a solvent and then dried. , Packaging materials used as bags, molded containers, packaging sheets or tubes.
2. Item ^2. The packaging material according to Item 1, wherein the amount of hydrophobic oxide fine particles attached is 0.01 to 10 g / m ² .
3. Item 3. The packaging material according to Item 1 or 2, wherein the hydrophobic oxide fine particles have a specific surface area of 50 to 300 m ² / g by BET method.
4). Item 2. The packaging material according to Item 1, wherein the hydrophobic silica has a trimethylsilyl group on its surface.
5. Item 5. The packaging material according to any one of Items 1 to 4 , wherein the porous layer having a three-dimensional network structure contains air.
6). Item 6. The packaging material according to any one of Items 1 to 5 , which is used for a product in which the content is packaged in a packaging material in a state in which the content can contact the outermost surface on the thermal adhesive layer side.

  The packaging material of the present invention can exhibit excellent non-adhesiveness while maintaining good thermal adhesiveness. That is, high non-adhesiveness can be obtained without impeding the thermal adhesiveness practically without being restricted by the type and thickness of the thermal adhesive layer. More specifically, at the time of thermal bonding, the hydrophobic oxide fine particles existing on the heat-bonded region are embedded in the heat-bonding layer and thus do not inhibit the heat-bonding, but exist outside the heat-bonded region. Since the hydrophobic oxide fine particles are held on the thermal adhesive layer as they are, their high non-adhesiveness can be exhibited.

  Further, according to the production method of the present invention, it is only necessary to impart hydrophobic oxide fine particles to the thermal adhesive layer, so there is no need to control the blending of additives into the raw materials constituting the thermal adhesive layer. This is advantageous in terms of production efficiency, cost, etc., because it is not necessary to control the mixing ratio. Moreover, as described above, it is advantageous in that the thermal bonding can be performed only by attaching the hydrophobic oxide fine particles to the entire surface without considering the bonding margin to the thermal bonding layer.

  Such packaging materials can be used as lidding materials, and are effective for various uses such as pillow bags, gusset bags, self-supporting bags, three-side seal bags, four-side seal bags, etc., molded containers, packaging sheets, tubes, etc. Can be used.

It is a schematic diagram of the cross-sectional structure of the packaging material of the present invention. It is a schematic diagram of the cross-sectional structure of the package produced using the packaging material of the present invention as a container lid. It is a figure which shows the result of having observed the cross-section in the packaging material obtained in the Example by FE (Field Emission) -SEM.

1 Base Material Layer 2 Thermal Adhesive Layer 3 Hydrophobic Oxide Fine Particles 4 Container 5 Contents

1. Packaging material The packaging material of the present invention is a packaging material comprising a laminate having at least a base material layer and a thermal adhesive layer, wherein the thermal adhesive layer is laminated as an outermost layer on one surface of the packaging material, Hydrophobic oxide fine particles having an average primary particle diameter of 3 to 100 nm are attached to the outermost surface where the thermal adhesive layer is not adjacent to other layers.

  FIG. 1 shows a schematic diagram of a cross-sectional structure of the packaging material of the present invention. The packaging material of FIG. 1 is composed of a laminate in which a thermal adhesive layer 2 is laminated on a base material layer 1. The thermal adhesive layer 2 is laminated on one outermost layer of the packaging material (laminate). In the thermal bonding layer 2 that is the outermost layer, hydrophobic oxide fine particles 3 having an average primary particle diameter of 3 to 100 nm are attached to the surface (outermost surface) on the side that is not adjacent to another layer (base material layer in FIG. 1). doing. The hydrophobic oxide fine particles 3 are adhered and fixed to the heat bonding layer 2. That is, even if the hydrophobic oxide fine particles and the content come into contact with each other, the hydrophobic oxide fine particles are adhered to such an extent that they do not fall off. In FIG. 1, the hydrophobic oxide fine particles 3 may contain primary particles, but it is desirable that the hydrophobic oxide fine particles 3 contain many aggregates (secondary particles). In particular, it is more preferable that the hydrophobic oxide fine particles form a porous layer having a three-dimensional network structure. That is, it is preferable that a porous layer having a three-dimensional network structure formed of hydrophobic oxide fine particles is laminated on the thermal bonding layer 2.

  In FIG. 2, the schematic diagram of the cross-sectional structure of the package body produced using the packaging material of this invention as a cover material of a container is shown. In FIG. 2, the description of the hydrophobic oxide fine particles 3 is omitted. The container 4 is filled with the contents 5 and sealed in such a state that the opening and the thermal adhesive layer 2 of the packaging material are in contact with each other. That is, the packaging material of the present invention is used in a state where the hydrophobic oxide fine particles adhering to the heat bonding layer 2 can come into contact with the contents 5. Even in such a case, the thermal adhesive layer 2 is protected by the hydrophobic oxide fine particles and has excellent non-adhesiveness. The adhesion of the contents to the thermal adhesive layer is blocked and repelled by the hydrophobic oxide fine particles (or the porous layer made of hydrophobic oxide fine particles). For this reason, the content does not remain in the vicinity of the thermal adhesive layer, but is repelled by the hydrophobic oxide fine particles (or the porous layer made of the hydrophobic oxide fine particles) and returns to the container. In addition, as a material of the container 4, it can select suitably from a metal, a synthetic resin, glass, paper, those composite materials, etc., The kind and component of a heat bonding layer can be adjusted suitably according to the material. Thus, the packaging material of the present invention has the contents in a state in which the contents can contact the outermost surface (particularly hydrophobic oxide fine particles (or a porous layer made of hydrophobic oxide fine particles)) on the thermal adhesive layer side. It can be suitably used for products in which an object is packaged in a packaging material.

  A known material or a laminated material can be adopted as the base material layer. For example, a simple substance such as paper, synthetic paper, a resin film, a resin film with a vapor deposition layer, 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 15-500 micrometers normally from viewpoints, such as the intensity | strength as a packaging material, a softness | flexibility, and cost.

  A well-known material can be employ | adopted as a heat contact bonding layer. For example, in addition to a known sealant film, a layer formed of an adhesive such as a lacquer type adhesive, an easy peel adhesive, or a hot melt adhesive can be employed. Among these, in the present invention, it is preferable to employ a lacquer type adhesive or a hot melt adhesive, and particularly a thermal adhesive layer (hot melt layer) formed by the hot melt adhesive can be suitably employed. When forming a hot melt layer, after applying the hot melt adhesive in a molten state, if the hydrophobic oxide fine particles are applied before cooling and solidifying, the hydrophobic oxide fine particles are allowed to adhere to the thermal adhesive layer as they are. Therefore, continuous production of the packaging material of the present invention is facilitated.

  The thickness of the thermal adhesive layer is not particularly limited, but it is usually preferably about 2 to 150 μm from the viewpoint of sealing performance, productivity, cost, and the like. In particular, in the packaging material of the present invention, when thermally bonding, the hydrophobic oxide fine particles existing on the heat bonded region are embedded in the heat bonding layer, and the heat bonding layer becomes the outermost surface so that the heat bonding is performed. It can be carried out. Therefore, it is desirable to set the thickness within the above thickness range so that as many hydrophobic oxide fine particles as possible can be embedded in the thermal adhesive layer.

  Hydrophobic oxide fine particles adhering to the thermal adhesive layer usually have an average primary particle diameter of 3 to 100 nm, preferably 5 to 50 nm, and more preferably 5 to 20 nm. By setting the average primary particle diameter in the above range, the hydrophobic oxide fine particles are in an appropriate aggregated state, and can hold a gas such as air in the voids in the aggregate, resulting in excellent non-adhesiveness. Can be obtained. That is, this agglomerated state is maintained even after adhering to the thermal adhesive layer, so that excellent non-adhesiveness can be exhibited.

  In the present invention, the average primary particle diameter can be measured with a scanning electron microscope (FE-SEM). When the resolution of the scanning electron microscope is low, other electrons such as a transmission electron microscope are used. You may carry out together with a microscope. Specifically, when the particle shape is spherical, the diameter is considered as the diameter, and when the particle shape is non-spherical, the average value of the longest diameter and the shortest diameter is regarded as the diameter, and 20 arbitrarily selected by observation with a scanning electron microscope or the like. The average diameter of the particles is defined as the average primary particle diameter.

The specific surface area of the hydrophobic oxide fine particles (BET method) is not particularly limited, and usually 50 to 300 m ² / g, it is preferable that the particular 100 to 300 m ² / g.

The hydrophobic oxide fine particles 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. These may be known or commercially available. For example, as silica, product names “AEROSIL R972”, “AEROSIL R972V”, “AEROSIL R972CF”, “AEROSIL R974”, “AEROSIL RX200”, “AEROSIL RY200” (above, manufactured by Nippon Aerosil Co., Ltd.), “AEROSIL R202” "AEROSIL R805", "AEROSIL R812", "AEROSIL R812S" (above, manufactured by Evonik Degussa). Examples of titania include “AEROXIDE TiO ₂ T805” (manufactured by Evonik Degussa). Examples of alumina include fine particles in which the product name “AEROXIDE Alu C” (manufactured by Evonik Degussa) is treated with a silane coupling agent to make the particle surface hydrophobic.

  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 R812” and “AEROSIL R812S” (both manufactured by Evonik Degussa).

The amount (weight after drying) of the hydrophobic oxide fine particles to be adhered to the thermal adhesive layer is not limited, but is usually preferably 0.01 to 10 g / m ^2, and preferably 0.2 to 1.5 g / m ^{2. 2} is more preferable, and 0.3 to 1 g / m ² is most preferable. By setting within the above range, more excellent non-adhesiveness can be obtained over a long period of time, and it is further advantageous in terms of suppression of falling off of hydrophobic oxide fine particles and cost. The hydrophobic oxide fine particles attached to the heat bonding layer preferably form a porous layer having a three-dimensional network structure, and the thickness is preferably about 0.1 to 5 μm, and preferably 0.2 to 2.5 μm. The degree is further preferred. By adhering in such a porous layer state, the layer can contain a lot of air, and more excellent non-adhesiveness can be exhibited.

  Further, the hydrophobic oxide fine particles may be attached to the entire surface of the thermal adhesive layer (the entire surface opposite to the base material layer side), or a region where the thermal adhesive layer is thermally bonded (so-called adhesive margin). It may be attached to the area excluding. In the present invention, even when adhering to the entire surface of the heat bonding layer, most or all of the hydrophobic oxide fine particles present on the heat bonded region are buried in the heat bonding layer, so that the heat bonding is hindered. In view of industrial production, it is desirable to adhere to the entire surface of the thermal adhesive layer.

2. Packaging Material Production Method The packaging material of the present invention is, for example, a method for producing a packaging material comprising a laminate having at least a base material layer and a thermal adhesive layer, and has an average primary particle diameter of 3 on the surface of the thermal adhesive layer. It can be suitably obtained by a method for producing a packaging material including a step of attaching hydrophobic oxide fine particles of ˜100 nm (hereinafter also referred to as “attachment step”).

  The laminate itself can be produced according to a known method. For example, with respect to a laminated material produced by a single layer base material or a dry laminating method, an extrusion laminating method, a wet laminating method, a heat laminating method, etc. A thermal adhesive layer may be formed by the method described in (1).

  The method for performing the attaching step is not particularly limited. For example, known methods such as roll coating, gravure coating, bar coating, doctor blade coating, brush coating, and electrostatic powder method can be employed. When roll coating or the like is employed, the adhesion step can be carried out by a method of forming a coating film on the thermal adhesive layer using a dispersion obtained by dispersing hydrophobic oxide fine particles in a solvent and then drying. The solvent in this case is not limited, and in addition to water, for example, alcohol (ethanol), cyclohexane, toluene, acetone IPA, propylene glycol, hexylene glycol, butyl diglycol, pentamethylene glycol, normal pentane, normal hexane, hexyl alcohol, etc. The organic solvent can be appropriately selected. At this time, a very small amount of a dispersant, a colorant, an anti-settling agent, a viscosity modifier and the like can be used in combination. The dispersion amount of the hydrophobic oxide fine particles with respect to the solvent is usually about 10 to 100 g / L. When drying, either natural drying or forced drying (heat drying) may be used, but industrially forced drying is preferable. The drying temperature is not limited as long as it does not affect the thermal adhesive layer, but is usually 150 ° C. or less, and preferably 80 to 120 ° C.

  In the manufacturing method of this invention, a laminated body can also be heated during the said adhesion process and / or after an adhesion process. By heating the laminate, the adhesion (fixing force) of the hydrophobic oxide fine particles to the thermal adhesive layer can be further increased. The heating temperature T in this case can be set as appropriate according to the type of the thermal adhesive layer and the like, and usually Tm−50 ≦ T ≦ Tm + 50 with respect to the melting point Tm (melting start temperature) ° C. It is preferable to be in the range. Further, the packaging material of the present invention may be subjected to embossing, half-cutting, notching, etc., as necessary, similarly to known packaging materials.

  The features of the present invention will be described more specifically with reference to the following examples and comparative examples. However, the scope of the present invention is not limited to the examples.

Examples 1-9 and Comparative Examples 1-3
Samples were prepared in which hydrophobic oxide fine particles were adhered to a laminate having each type of thermal bonding layer as shown in Table 1. Specifically, each sample was produced as follows.

(1) Production of laminate

<Hot melt type>
Using a polyurethane dry laminate adhesive (weight after drying: 3.5 g / m ² ; abbreviated as D) on one side of a 15 μm thick aluminum foil (1N30, soft foil; abbreviated as AL), back printing (abbreviated as printing) The substrate was bonded to the printed surface of a 12 μm thick polyethylene terephthalate film (abbreviated as PET). The aluminum surface of this base material layer was subjected to an anchor coat (main component: polyester resin; abbreviated as AC) treatment, and a low density polyethylene resin (abbreviated as LDPE) was extruded and laminated to a film thickness of 20 μm after drying. . Further, a gravure hot so that a hot melt agent (35 parts by weight of wax, 35 parts by weight of rosin and 30 parts by weight of ethylene-vinyl acetate copolymer; abbreviated as HM) is dried on low density polyethylene to a weight of 20 g / m ^2. Melt coated. As a result, a laminate having a configuration of “PET / printing / D / AL / AC / LDPE / HM” was obtained.

<Sealant type>
Using a polyurethane dry laminate adhesive (weight after drying: 3.5 g / m ² ; abbreviated as D) on one side of a 15 μm thick aluminum foil (1N30, soft foil; abbreviated as AL), back printing (abbreviated as printing) The substrate was bonded to the printed surface of a 12 μm thick polyethylene terephthalate film (abbreviated as PET). The aluminum surface of this base material layer is subjected to anchor coating (main component: polyester resin; abbreviated as AC), and then a sealant having a thickness of 30 μm using a low density polyethylene resin (film thickness after drying: 20 μm; abbreviated as LDPE). A film (main component: metallocene-catalyzed polyethylene; abbreviated as sealant) was extruded and laminated. As a result, a laminate having a configuration of “PET / printing / D / AL / AC / LDPE / sealant” was obtained.

<Lacquer type>
Using a polyurethane dry laminate adhesive (weight after drying: 3.5 g / m ² ; abbreviated as D) on one side of a 15 μm thick aluminum foil (1N30, soft foil; abbreviated as AL), back printing (abbreviated as printing) The substrate was bonded to the printed surface of a 12 μm thick polyethylene terephthalate film (abbreviated as PET). A separately prepared polyethylene terephthalate film (abbreviated as PET) having a thickness of 12 μm was bonded to the aluminum surface of the base material layer using a polyurethane dry laminate adhesive (weight after drying: 3.5 g / m ² ; abbreviated as D). Furthermore, a heat seal lacquer (main component: acrylic resin + polyester resin: abbreviated as lacquer) was applied after drying to a weight of 5 g / m ² . In this way, a laminate having a configuration of “PET / printing / D / AL / D / PET / lacquer” was obtained.

(2) Adhesion of hydrophobic oxide fine particles 5 g of hydrophobic oxide fine particles (product name “AEROSIL R812S” manufactured by Evonik Degussa, BET specific surface area: 220 m ² / g, primary particle average diameter: 7 nm) are dispersed in 100 mL of ethanol. A coating solution was prepared. After applying this coating liquid to the surface of the thermal adhesive layer of the laminate prepared in (1) above by a gravure coating method or a bar coating method so that the weight after drying is 0.3 to 1.0 g / m ^2. The sample (packaging material) was obtained by drying at 100 ° C. for about 10 seconds to evaporate ethanol.

(3) Observation (confirmation) of porous layer made of hydrophobic oxide fine particles
In the packaging material of the example, the structure of the layer made of hydrophobic oxide fine particles was observed by FE-SEM. As a result, a porous layer having a three-dimensional network structure formed of hydrophobic oxide fine particles was observed for any packaging material. As an example, the observation result of Example 4 (A) is shown in FIG. As shown in FIG. 3, a layer in which black and white are mixed is recognized on the heat bonding layer (sealant). This white portion is a porous layer made of a hydrophobic oxide. Thus, it turns out that the porous layer which consists of hydrophobic oxide microparticles | fine-particles is formed by apply | coating and drying the said coating liquid.

Test example 1 (seal strength)
The seal strength of the samples obtained in each example and comparative example was examined.

About Examples 1-6 and Comparative Examples 1-2 A package was produced using a lid material cut out from each packaging material into a lid material shape (circular shape with a tab of 75 mm in diameter). Specifically, a flanged paper / polyethylene container (with a flange width of 3 mm, a flange outer diameter of 70 mm, a height of about 55 mm, an internal volume of about 130 cm ³ and a thickness of about 300 μm coated with 100 μm of polyethylene on the inside of the container. Each of the packaging bodies was produced by heat-sealing the lid material on the flanges of the molded product. The heat sealing conditions were a temperature of 160 ° C. and a pressure of 1 kg / cm ² for 1 second. Pull the tab of the lid on each package from the opening start point at an angle of elevation of 45 degrees at a speed of 100 mm / min. The maximum load at the time of opening is the seal strength (N), and n = 6 points for each package The average value was obtained. The results are shown in Table 1.

About Examples 7-9 and Comparative Example 3 A package was produced using a lid material cut out from each packaging material into a lid material shape (rectangular length 62 mm × width 67 mm). Specifically, the lid material is heated on the flange of a flanged polystyrene container (formed with a flange width of 4 mm, a flange outer diameter of 60 mm × 65 mm □, a height of about 48 mm, and an internal volume of about 100 cm ³ ). Each package was produced by sealing. The heat seal conditions were a ring (concave) seal with a width of 2 mm in 1 second at a temperature of 210 ° C. and a pressure of 2 kg / cm ² . Pull the tab of the lid on each package from the opening start point at an angle of elevation of 45 degrees at a speed of 100 mm / min. The maximum load at the time of opening is the seal strength (N), and n = 6 points for each package The average value was obtained. The results are shown in Table 1.

Test Example 2 (Sealing property (puncture strength))
Using the package produced in Test Example 1 as a test sample, sealing strength test according to the sealing strength test method of {Ministerial Ordinance on Milk and Dairy Product Component Standards (April 16, 1979 Ministry of Health and Welfare Ordinance No. 17)} Went. However, the internal pressure (mmHg) at the time when air continued to flow into the container and air leaked was measured. N = 3 points were measured for each package, and the average value was determined. The results are shown in Table 1.

Test Example 3 (Contact angle)
The contact angle measuring device (solid-liquid interface analyzer “Drop Master 300” manufactured by Kyowa Interface Science Co., Ltd.) was used to measure the contact angle of pure water using the thermal adhesive layer side of each packaging material as a test surface. The results are shown in Table 1.

Test example 4 (drop angle)
Use the heat adhesive layer side of each packaging material as the test surface and fix it with a clip on a horizontal flat table with this surface as the top surface. Commercial yogurt (product name “Delicious Caspian Sea” soft yogurt, 1 drop manufactured by Glico Dairies Co., Ltd .: approx. 0.4 g) was hung from the closest distance, the horizontal flat was tilted, and the angle at which the yogurt droplet fell was determined. The results are shown in Table 1. In addition, Comparative Examples 1-3 flowed down without falling even at 90 degrees.

Test example 5 (transport test)
100 g (flanged paper / polyethylene container) and 85 g (flanged polystyrene container) of commercially available yogurt (product name “Delicious Caspian Sea” soft yogurt, manufactured by Glico Dairies Co., Ltd.) in the package used in Test Example 1 Each was filled, and the lid was heat sealed in the same manner as in Test Example 1. After the package filled with yogurt was transported by a long distance truck at a distance of 1500 km, the lid was opened with fingers, and the state of the surface of each lid on the side of the thermal adhesive layer was visually observed. The results are shown in Table 1. The evaluation is “◎” when there is no yogurt adhering, and “○” when there is some ring-like adhering in the periphery (adhesive area ratio 20% or less), and the adhering is slightly noticeable (adhesive area) The ratio was more than 20% and less than 90%), and the case where adhesion was found on almost the entire surface (adhesion area ratio of 90% or more) was marked with “X”. In this case, “◎” and “◯” are evaluated as good.

  As is clear from the results in Table 1, the non-adhesive property is not exhibited at all in the conventional product (comparative example), whereas the high non-adhesive property is exhibited in the present invention (example). . In addition, it can be seen that the present invention shows good performance that is practically satisfactory in terms of seal strength and sealability (puncture value). Moreover, it turns out that the packaging material of this invention shows high non-adhesiveness also from the result of a contact angle and a fall angle. In particular, the outermost surface on the thermal adhesive layer side of the packaging material of the present invention (the surface on which hydrophobic oxide fine particles are adhered) has a contact angle of pure water of 150 degrees or more, which is superior to conventional packaging materials. It has non-adhesive contents.

Claims (6)

A packaging material used for packaging foods, beverages, pharmaceuticals, cosmetics or chemicals, which is a packaging material comprising a laminate having at least a base material layer and a thermal adhesive layer, wherein the thermal adhesive layer is a packaging material. Hydrophobic oxide fine particles having a primary particle average diameter of 3 to 100 nm are adhered to the outermost surface, which is laminated as the outermost layer on one side, and the thermal adhesive layer is not adjacent to the other layer, and the hydrophobic oxide fine particles Is a hydrophobic silica, and the hydrophobic oxide fine particles form a porous layer having a three-dimensional network structure. Embedded in the thermal adhesive layer ,
The porous layer having the three-dimensional network structure is formed by a method in which a coating film is formed on a thermal adhesive layer using a dispersion obtained by dispersing hydrophobic oxide fine particles in a solvent and then dried. , Packaging materials used as bags, molded containers, packaging sheets or tubes. The packaging material of Claim 1 whose adhesion amount of hydrophobic oxide microparticles | fine-particles is 0.01-10 g / m < ² >. The packaging material of Claim 1 or 2 whose specific surface area by BET method of hydrophobic oxide microparticles | fine-particles is 50-300 m < ² > / g. The packaging material according to claim 1, wherein the hydrophobic silica has a trimethylsilyl group on the surface thereof. The packaging material according to any one of claims 1 to 4 , wherein air is contained in a porous layer having a three-dimensional network structure. The packaging material in any one of Claims 1-5 used for the product by which the said content is packaged in a packaging material in the state which can contact the content on the outermost surface by the side of a heat bonding layer.