Heat-insulating packaging film, packaging bag, and packaging bag having opening member

DESCRIPTION

Heat insulating packaging film, packaging bag and packaging bag having opening member

Technical field

The present invention relates to a heat insulating (heat insulating) packaging film for a packaging bag containing foods such as frozen desserts that require a heat insulating property. Furthermore, the present invention relates to a packaging bag and a packaging bag having an opening member (a spout) for foods such as frozen desserts that require a heat-insulating property.

Background of the technique

Conventionally, frozen desserts, such as ice cream, are packaged in a cup or tube type container when sold. However, a tube-type receptacle in which a frozen dessert has been packaged presents the problem of cooling the consumer's hand when holding the receptacle in the hand. Furthermore, although the cup-type receptacle does not cool the hand as much as the tube-type receptacle, it has also presented the problem that both hands are needed to eat the food in the receptacle.

In recent years, a gusseted packaging bag having a heat insulating film has been used as a container for packaging frozen desserts. As a heat insulating film, a foamed resin layer has been described in Patent Document 1.

Prior art document

Patent Document

Patent Document 1 Japanese Unexamined Patent Application, First Publication No. 2001-130586.

In European Patent EP 1 291 300 reference is made to a multilayer core for vacuum insulation panel and insulated container including a vacuum insulation panel.

Compendium of the invention

Problems to be solved by the invention

However, since the packaging bag described in Patent Document 1 has a foamed resin layer with a thickness of 500 pm, compared to a general packaging film with a thickness of about 30 pm to about 200 pm, it has the problem that the thickness of the packaging bag is considerably large. In other words, it is preferable that the thickness of the foamed resin layer is reduced as much as possible, taking into account the depletion and recycling of fossil fuels.

Taking into account the above-mentioned circumstances, it is an object of the present invention to provide a heat-insulating packaging film, a packaging bag and a packaging bag having an opening member (a nozzle) that has a sufficiently high heat-insulating property and allows a decrease in their weight.

Means to solve problems

[1] A heat insulating packaging film including a base material and an open cell layer disposed on one face of the base material and made of polyolefin, wherein the mean diameter of an opening of the open cell layer is greater than the thickness of the open cell layer.

[2] In the above heat insulating packaging film, the average diameter of the aperture hole in the open cell layer can range from 150 pm to 500 pm.

[3] In the above heat insulating packaging film, a foaming rate of the open cell layer can vary from 1.2 to 3.5 times.

[4] In the above heat insulating packaging film, the film may include a non-foamed sealant layer disposed on the opposite side of the open cell layer to the base material.

[5] In the above heat insulating packaging film, the thickness of the open cell foamed layer can range from 70 pm to 250 pm.

[6] A packaging bag formed by heat sealing the thermal insulation packaging film according to any one of the above [1] to [5].

[7] A packaging bag having an opening member (a nozzle), including the packaging bag according to the above [6] and an opening member (a nozzle) attached to the packaging bag to communicate a

ES 2 744 580 T3 inner side with an outer side thereof.

Effect of the invention

The heat-insulating packaging film, the packaging bag and the packaging bag having an opening member (a nozzle) of the present invention have a sufficiently high heat-insulating property.

Brief description of the drawings

Figure 1 is a cross-sectional view illustrating an exemplary embodiment of a heat insulating packaging film of the present invention;

Figure 2 is a scanning electron microscope (SEM) photograph of an open cell layer;

Figure 3 is an SEM photograph of a closed cell layer and

Fig. 4 is a perspective view showing an exemplary embodiment of a packaging bag having an opening member (a nozzle) of the present invention.

Modes for carrying out the invention

Heat Insulating Packaging Film

Hereinafter, an exemplary embodiment of a heat insulating packaging film of the present invention will be described in detail.

Figure 1 shows a heat insulating packaging film 10 in accordance with an exemplary embodiment of the present invention. The heat insulating packaging film 10 according to the present embodiment includes a base material 11, an open cell layer 12 that is in contact with the base material 11 and a sealant layer 13 arranged on the opposite side of the open cell layer 12 to base material 11).

Base material

The base material 11 is a film that has mechanical strength and is arranged on the surface when used.

The film used for the base material 11 may include a synthetic resin film, for example, polyamide, polyethylene terephthalate, polypropylene, ethylene vinyl alcohol copolymer, polycarbonate, polyacetal or the like.

Alternatively, the film used for the base material 11 may include a laminated film prepared by stacking the synthetic resin described above in multiple layers and extruding the layers under high pressure. The above films can be an unstretched film or a mono- or biaxially stretched film. In view of printability, the mono- or biaxially stretched film is preferably used. Furthermore, among the above film-forming synthetic resins, polyethylene terephthalate is preferably used in view of the printability and the ability to resist impact.

The base material 11 may have a thickness of from 6 pm to 50 pm, more preferably from 9 pm to 25 pm. When the thickness of the base material 11 is 6 pm or more, the strength of the heat-insulating packaging film 10 can be increased. When the thickness of the base material 11 is 50 µm or less, the heat insulating packaging film 10 can have flexibility.

Open cell layer

The open cell layer 12 is made up of stacked mesh-like layers, as shown in the SEM photograph of FIG. 2 and is substantially a layer of polyolefin foam having continuous communicating or unifying bubbles within it. In other words, the open cell layer 12 includes several openings in the surface thereof, as well as an air layer therein.

The polyolefin used for the open cell layer 12 can include, for example, low density polyethylene, linear low density polyethylene, medium density polyethylene, high density polyethylene, polypropylene or the like.

Meanwhile, the open cell layer 12 can be formed using a base resin in the form of a simple substance. Alternatively, to promote continuous foaming, the base resin can be mixed with a foam promoting resin with a relatively low melt stress compared to the base resin. In this case, the melt stress of the foam promoting resin may be less than 60% of the melt stress of the base resin. Furthermore, the mixing ratios of the base resin and the foam promoter resin may range from 100: 0 to 30:70, preferably 80:20 to 40:60. The foam promoting resin can be selected from low density polyethylene, linear low density polyethylene, medium density polyethylene, high density polyethylene, polypropylene or the like. Furthermore, a combination of the base resin and the foam promoting resin is more preferably a mixture of the low density polyethylene as the base resin and the linear low density polyethylene as the foam promoting resin.

ES 2 744 580 T3

A foaming rate of the open cell layer 12 preferably ranges from 1.2 to 3.5 times, more preferably 1.5 to 3.0 times. When the foaming rate of the open cell layer 12 is 1.2 times or more, the heat insulating properties can be further increased. In addition, when the foaming rate of the open cell layer 12 is 3.5 times or less, the workability is improved. Such a foaming rate is calculated according to a ratio of the bulk density of a film before foaming to that occurring after foaming.

An average hole diameter of the open cell layer 12 preferably ranges from 150 µm to 500 µm, more preferably, from 200 µm to 350 µm. When the mean diameter of the hole of the open cell layer 12 is not less than the above lower limit, the heat insulating properties can be further increased. When the mean diameter of the hole of the open cell layer 12 is not larger than the above upper limit, fracture of the open cell layer 12 during manufacturing can be prevented. Meanwhile, the average hole diameter of an opening in the surface of the open cell layer is greater than the layer thickness of the open cell layer itself. Also, in the foam of a closed cell layer (independently foamed) including bubbles in the layer, between the layers to be described in the comparative examples below, the minimum hole diameter of each bubble in a thickness direction does not exceed of a thickness of the foam.

The mean diameter of the hole can be calculated by taking an electron micrograph of the surface of the open cell layer 12 and analyzing the image obtained. In this regard, according to the present invention, the mean hole diameter refers to an average value of aperture sizes in the surface of the open cell layer, which is a numerical average value of cells having a diameter hole of 100 pm or more.

The thickness of the open cell layer 12 preferably ranges from 70 µm to 250 µm, more preferably from 100 µm to 200 µm. When the thickness of the open cell layer 12 is 70 µm or more, the heat insulating properties can be further increased. When the thickness of the open cell layer 12 is 250 µm or less, the flexibility of the heat insulating packaging film 10 can be further improved. Meanwhile, the actual resin thickness of the foamed layer can be calculated by dividing the thickness of a foamed layer by a foaming rate.

Sealant layer

The sealant layer 13 is a non-foamed layer that can be heat sealed. The thermoplastic resin used to form the sealant layer 13 may include, for example, low-density polyethylene, linear low-density polyethylene, medium-density polyethylene, high-density polyethylene, polypropylene, or the like. Among these, linear low-density polyethylene is preferably used in view of the ability to resist cold and strength.

A thickness of the sealant layer 13 preferably ranges from 10 µm to 200 µm, and more preferably from 20 µm to 100 µm. When the thickness of the sealant layer 13 is 10 pm or more, a sufficient heat sealing property can be ensured. When the thickness of the sealant layer 13 is 200 µm or less, the flexibility of the heat-insulating packaging film 10 can be further improved.

Preparation of heat-insulating packaging film

The heat insulating packaging film 10 is prepared by laminating the base material 11, the open cell layer 12 and the sealant layer.

Although a method of laminating the base material 11 and the open cell layer 12 may include, for example, dry lamination, extrusion lamination, etc., dry lamination is preferably used, in view of excellent bond strength.

When lamination is done by dry lamination, an adhesive used herein may include, for example, a polyurethane adhesive, a polyacryl adhesive, a polyester adhesive, a polyether adhesive , an epoxy resin adhesive , a polyvinyl acetate adhesive, a cellulose adhesive or the like.

Although a method of laminating the open cell layer 12 and the sealant layer 13 may include, for example, dry lamination, extrusion lamination, coextrusion, etc., coextrusion is preferably used as it does not require a binder and can be omitted. generating an unpleasant odor.

More particularly, a method for the preparation of the heat insulating packaging film preferably includes preparing a laminated material of the open cell layer 12 and the sealing layer 13 by coextrusion and adhering the base material 11 to the open cell layer 12 of the material. laminated by means of dry lamination.

For example, the open cell layer 12 can be prepared by processing a polyolefin composition, containing polyolefin and a foaming agent, in the form of a layer, and then heating and foaming the processed layer.

The foaming agent may include, for example, an organic chemical foaming agent for generating nitrogen gas, including azo coloring compounds such as azodicarbonamide, barium azocarboxylate or azobisisobutylnitrile compounds, etc., nitroso compounds such as N, N'-dinitrosopentamethylenetetramine, compounds of hydrazine such as hydrazocarboamide, hydrazide compounds such as p-toluenesulfonylhydrazide, p, p'-oxy-bis (benzenesulfonylhydrazide), etc .; an inorganic chemical agent for generating carbonic acid gas, such as hydrochloride

ES 2 744 580 T3 of sodium, ammonium carbonate, ammonium hydrocarbonate, etc .; lower aliphatic hydrocarbon compounds such as propane, n-butane, i-butane, n-pentane, i-pentane, hexane, etc .; alicyclic hydrocarbon compounds such as cyclobutane, cyclopentane, etc .; aromatic hydrocarbon compounds such as benzene, toluene, xylene, etc .; Low-boiling halogenated hydrocarbon compounds including lower aliphatic monovalent alcohol compounds such as methanol, ethanol, etc., lower aliphatic ketone compounds such as acetone, methyl ethyl ketone, etc., chloromethyl, chloroethyl, 1-chloro-1,1 -difluoroethane or the like or a physical foaming agent that includes gases such as argon, helium, freon, carbonic acid gas (carbon dioxide gas), nitrogen gas, etc.

Meanwhile, the gas used in the present invention may include subcritical or supercritical fluids, as well as a fluid in a vapor state.

Among the above foaming agents, in view of the suitable use for food, carbon dioxide gas or nitrogen gas is preferably used, and carbon dioxide gas or nitrogen gas in the supercritical state is particularly preferably used.

An added amount of the foaming agent can vary from 0.01 part by weight to 2.0 part by weight with respect to 100 parts by weight of polyolefin. When the added amount of the foaming agent is 0.01 part by weight or more, an open cell layer can be easily formed. In addition, when the added amount is 2.0 parts by weight or less, it is easy for the mean diameter of the hole to be 500 pm or less.

During foaming, the setting temperature of an extruder can be suitably regulated depending on the types or amounts added of foaming agent and the types of polyolefin.

Functional effects

The open cell layer 12 has an opening in its surface and a layer of air present in the same layer. Accordingly, a laminated material having the open cell layer 12 includes a fine irregularity formed on its surface to form a shape of the opening in the surface of the open cell layer 12 and the air layer formed in an intermediate layer of the laminated material. Therefore, the synergistic effects of the unevenness and the air layer can allow the laminated material having the open cell layer 12 to exhibit greater thermal insulation effects compared to the closed cell layer (independently formed) described in the comparative examples below. The heat-insulating packaging film 10 having the open-cell layer 12 has low heat conductivity and sufficiently high heat-insulating properties. As a result of the investigations carried out by the present author, it was found that the film of the invention has better heat-insulating properties compared to the heat-insulating packaging film using a closed cell layer shown in the SEM photograph of fig. 3. Since the heat-insulating packaging film 10 has improved heat-insulating properties, it is possible to easily decrease the thickness and weight of the film itself.

Packaging bag

Hereinafter, a packaging bag in which the heat insulating packaging film 10 is used will be described in detail.

The packaging bag of the present exemplary embodiment can be manufactured by heat sealing the heat insulating packaging film. The heat-insulating packaging film 10 is arranged such that the base material becomes a surface of the film while the sealant layer 13 is placed within the same film.

To make a packaging bag by heat sealing the thermally insulated packaging film 10, for example, a manufacturing method that includes: overlapping two sheets of the heat-insulating packaging films 10 and 10 in a substantially rectangular shape to allow the sealing layers 13 and 13 to face each other and, in this state, it may be proposed to use a heat sealing bar to execute the sealing with heat surrounding the entire periphery on four sides.

Alternatively, another manufacturing method including: folding a single sheet of the heat-insulating packaging film 10 into two layers so that the sealing layers 13 are facing each other and, in this state, the use of a sealing bar with heat to perform heat sealing around most of the periphery of three sides, except the folded side.

Alternatively, the heat insulating packaging film 10 may be heat sealed to make a packaging bag so as to form a side-sided gusset-type bag. That is, a side-side forming film is first prepared having a sealant layer arranged on one side thereof, and then the prepared side-side forming film is folded into two layers to allow the sealing layer to become a external side. Next, two sheets 10 and 10 of the heat-insulating packaging films are superimposed in a substantially rectangular shape, so that the sealing layers 13 and 13 face each other and the side-side forming film that was folded is placed between the two sheets of the heat insulating packaging films 10 and 10 to be placed on the side side parts. Then, in this state, the heat seal is performed by surrounding the entire periphery of four sides using a heat seal bar. As a result, a reinforcement bag is obtained and the corresponding faces of the side-side forming film folded in all four

ES 2 744 580 T3 edges can be thermally bonded or adhered to each other.

Spout packaging bag

Hereinafter, a packaging bag having a nozzle formed using the heat insulating packaging film 10 will be described in detail.

Fig. 4 shows the packaging bag having a nozzle of an exemplary embodiment of the present invention. The packaging bag 1 having a nozzle according to a present exemplary embodiment includes a nozzle 3 attached to a packaging bag 2.

The packaging bag 2 in the present exemplary embodiment is manufactured by heat sealing the heat-insulating packaging film 10 and may be a backing bag having side-side portions 2a.

The nozzle 3 is a tubular body through which an internal side of the packaging bag 2 communicates with an external side thereof.

Materials used to manufacture nozzle 3 may include, for example, polyolefin, polyamide, polyester, (meth) acryl resin, polyvinyl chloride, polyvinylidene chloride, polyethersulfone, ethylene vinyl alcohol copolymer or the like. Among these, polyolefin is preferably used as it can be heat sealed to heat insulating packaging film 10.

Examples of the polyolefin can include: polyethylene resin such as high density polyethylene, medium density polyethylene, high pressure low density polyethylene, linear low density polyethylene, ethylene vinyl acetate copolymer, etc .; olefin elastomer such as ethylene-a-olefin copolymer; polypropylene resin such as polypropylene, ethylene-propylene random copolymer, α-olefin-propylene random copolymer, etc. or cyclic polyolefin resin. These resins can be mixed or partially cross-linked to improve their performance.

The nozzle 3 can be manufactured using a single material or formed in a multilayer structure including multiple layers of resin.

As the mounting method of the nozzle 3 in the packaging bag manufacturing method, a method may be proposed including: interposing one end of the nozzle 3 between the heat-insulating packaging films 10 and 10 at a peripheral edge, followed by heat sealing .

The packaging bag or the packaging bag 1 having a nozzle including the heat-insulating packaging film 10 achieves excellent heat-insulating properties. Therefore, in the case where a frozen dessert is packed in the packaging bag or the packaging bag 1 has a spout, it is possible to prevent the consumer's hands or fingers from becoming too cold when pressing the bag with the hands or fingers to remove frozen dessert from bag 1. Similarly, in the case where hot foods are packed in the packing bag or packing bag 1 having a nozzle, it is possible to prevent the consumer's hands or fingers from becoming too hot when pressing the bag with the hands or fingers to remove hot food from bag 1.

Other exemplary embodiments

The present invention is not particularly limited to the embodiments described above.

For example, the heat-insulating packaging film of the present invention may further include a functional layer to provide such features as gas protection properties, toughness, ability to resist bending, ability to resist puncture, ability to resist impact, ability to resist abrasion, ability to resist cold or the like.

For example, a base material layer, a functional layer, an open cell resin layer, and a sealant layer on the side of the base material layer may be arranged in this order.

The functional layer can include, for example, metallic foil or various plastic films, etc.

The metals used to manufacture the metallic foil can include, for example, aluminum, iron, copper, magnesium, etc.

Plastic films can include, for example, a plastic film such as polyethylene, polypropylene, polyethylene terephthalate, polyamide, polyvinyl chloride, polycarbonate, polyacrylonitrile, polyvinyl alcohol, ethylene-vinyl alcohol copolymer, etc .; a plastic film coated with a gas protection resin such as polyvinylidene chloride, etc. or a plastic film deposited with an inorganic substance such as aluminum, silicon oxide, aluminum oxide, magnesium oxide, etc. or similar.

The functional layer can be a single layer or at least two or more layers.

ES 2 744 580 T3

A thickness of the functional layer can vary from 6 pm to 30 pm. When the thickness of the functional layer is 6 pm or more, the effects of the functional layer can be sufficiently produced. When the thickness of the functional layer is 30 µm or less, the heat insulating packaging film can have sufficient flexibility.

Also, the sealant layer can be omitted from the heat-insulating packaging film. When the sealant layer is omitted, the open cell layer can function as the sealant layer.

Example

Example 1

Using an air-cooled inflation molding machine capable of forming a two-component double layer, a laminate was prepared that included a non-foamed sealant layer having a thickness of 60 pm and an open cell layer having a thickness 100 pm by coextrusion.

The sealant layer was prepared by melting a linear low-density polyethylene at a temperature of 200 ° C and discharging the molten material from a die of the inflation molding machine.

Furthermore, the open cell layer was prepared by melting a polyethylene composition, which included 60 parts by weight of low density polyethylene (melt stress: 190 mN), 40 parts by weight of polypropylene (melt stress: 100 mN) and 1 part by weight of sodium hydrochloride as a foaming agent at a temperature of 200 ° C and discharging the molten material from the die of the inflation molding machine. The foaming rate of the open cell layer was 2.4 times and the mean hole diameter thereof was 252 pm. Also, the actual thickness of the open cell layer resin was about 41.7 µm.

A biaxially stretched polyethylene terephthalate film having a thickness of 12 pm was adhered to the open cell layer of the laminate material obtained by dry lamination using a polyester adhesive as a binder, resulting in a heat insulating packaging film .

Example 2

Using an air-cooled inflation molding machine capable of forming a two-component double layer, a laminate was prepared that included a non-foamed sealant layer having a thickness of 60 pm and an open cell layer having a thickness 140 pm by coextrusion. The sealant layer was prepared by melting a linear low-density polyethylene at a temperature of 200 ° C and discharging the molten material from a die of the inflation molding machine.

In addition, the open cell layer was prepared by melting a polyethylene composition, which included 100 parts by weight of low-density polyethylene (melt stress: 174 mN), 20 parts by weight of linear low-density polypropylene (melt stress: 38 mN) and 0.4 parts by weight of nitrogen gas in the supercritical state as a foaming agent at a temperature of 200 ° C and discharging the molten material from the die of the inflation molding machine. The foaming rate of the open cell layer was 2.5 times and the mean hole diameter was 275 pm. Furthermore, the actual thickness of the open cell layer resin was approximately 56 µm.

A biaxially stretched polyethylene terephthalate film having a thickness of 12 pm was adhered to the open cell layer of the laminate material obtained by dry lamination using a polyester adhesive as a binder, resulting in a heat insulating packaging film .

Comparative Example 1

Using an air-cooled inflation molding machine capable of forming a two-component double layer, a laminated material was prepared that included a non-foamed sealant layer having a thickness of 20 pm and a closed seal layer having a thickness 140 pm by coextrusion.

The sealant layer was prepared by melting a linear low-density polyethylene at a temperature of 200 ° C and discharging the molten material from a die of the inflation molding machine.

Furthermore, the closed cell layer was prepared by melting a polyethylene composition, which included 100 parts by weight of low density polyethylene and 1 part by weight of azodicarbonamide at a temperature of 200 ° C and discharging the molten material from the die of the machine. inflation molding. A foam rate of the closed cell layer was 1.3 times. A separate foamed body cell was not spherical but had a flat shape. The cell of the independently foamed body was not circular in a surface direction, but stretched in the direction of flow to obtain an elliptical shape. The independently foamed body had an average orifice diameter in the flow direction of 350 µm, an average orifice diameter in the width direction of 65 µm, and an average orifice diameter in the thickness direction of 15 µm. The actual thickness of the closed cell layer resin was approximately 107.7 µm.

A biaxially stretched polyethylene terephthalate film having a thickness of 12 pm was adhered to the closed cell layer of the laminated material obtained by dry lamination using a polyester adhesive as

ES 2 744 580 T3 binder, resulting in a heat insulating packaging film.

Comparative Example 2

A biaxially stretched polyethylene terephthalate film having a thickness of 12 pm was adhered to a sealant layer (a linear low density polyethylene film) having a thickness of 70 pm by dry lamination using a polyester adhesive. as a binder, resulting in a packaging film.

Comparative Example 3

Using an air-cooled inflation molding machine capable of forming a two-component double layer, a laminated material was prepared including a non-foamed sealant layer having a thickness of 60 pm and a closed cell layer having a thickness 175 pm by coextrusion. The sealant layer was prepared by melting a linear low-density polyethylene at a temperature of 200 ° C and discharging the molten material from a die of the inflation molding machine.

Furthermore, the closed cell layer was prepared by melting a polyethylene composition, which included 100 parts by weight of low density polyethylene and 1 part by weight of azodicarbonamide at a temperature of 200 ° C and discharging the molten material from the die of the machine. inflation molding. A foam rate of the closed cell layer was 1.3 times. A separate foamed body cell was not spherical but had a flat shape. The cell of the independently foamed body was not circular in a surface direction, but stretched in the direction of flow to obtain an elliptical shape. The independently foamed body had an average orifice diameter in the flow direction of 300 µm, an average orifice diameter in the width direction of 70 µm, and an average orifice diameter in the thickness direction of 20 µm. The actual thickness of the closed cell layer resin was approximately 134.7 µm.

A biaxially stretched polyethylene terephthalate film having a thickness of 12 pm was adhered to the closed cell layer of the laminated material obtained by dry lamination using a polyester adhesive as a binder, resulting in a heat insulating packaging film .

Evaluation

Evaluation of the thermal insulation properties as a function of the temperature of the finger surface

After each heat insulating packaging film was cut into pieces having sizes of 80mm x 125mm and three heat seal pieces at a heat seal temperature of 180 ° C, 140 ml of tap water was filled through the face. remaining unsealed. Then the remaining face was also heat sealed to obtain a packaging bag containing tap water. The packaging bag was left in a -18 ° C freezer for 24 hours (for a full day and night).

Subsequently, the packaging bag was taken out of the freezer and held with four different fingers of the thumb, while a balance weight of 500 g was placed on the packaging bag. After this, after placing the packaging bag on the fingers, the temperature of the surface of the fingers was measured after 5 seconds, 10 seconds, 15 seconds, 20 seconds, 25 seconds and 30 seconds. The finger surface temperature was determined for the respective fingers by thermography, after separating the packaging bag from the four fingers. Table 1 shows the measured surface temperature of the fingers. The results shown in Table 1 are average values ​​of the surface temperatures of the four fingers.

Table 1

<td rowspan="2">Time (second)</td><td colspan="5">Finger surface temperature (° C)</td>

<td>Example 1</td><td>Example 2</td><td>Comparative Example 1</td><td>Comparative Example 2</td><td>Comparative Example 3</td>

<td> 5</td><td> 21,0</td><td> 22,5</td><td> 20,9</td><td> 15,2</td><td> 21,1</td>

<td> 10</td><td> 20,8</td><td> 21,8</td><td> 17,2</td><td> 12,4</td><td> 20,7</td>

<td> 15</td><td> 20,8</td><td> 21,5</td><td> 17,0</td><td> 11,2</td><td> 20,8</td>

<td> 20</td><td> 17,9</td><td> 19,5</td><td> 15,9</td><td> 11,2</td><td> 18,1</td>

<td> 25</td><td> 14,1</td><td> 16,8</td><td> 12,6</td><td> 10,8</td><td> 14,0</td>

<td> 30</td><td> 13,9</td><td> 16,5</td><td> 12,6</td><td> 10,8</td><td> 13,8</td>

The packaging bag manufactured using the heat insulating packaging film having an open cell layer in each of Examples 1 and 2 exhibited a delayed decrease in finger surface temperature and excellent heat insulation properties.

Meanwhile, the packaging bag manufactured using the heat insulating packaging film which had a layer

Closed cell ES 2 744 580 T3 as a heat insulating packaging film in Comparative Example 1 exhibited a rapid decrease in finger surface temperature.

The packaging bag manufactured using the packaging film without a heat-insulating layer in Comparative Example 2 had almost no heat-insulating properties.

The packaging bag manufactured using the packaging film in Comparative Example 3 had heat-insulating properties substantially the same as in Example 1. However, since the actual thickness of the resin in the foamed layer was 3 times or more than that of the example 1, the thermal insulation efficiency is considerably lower than that of example 1.

That is, Examples 1 and 2 exhibited superior heat insulation properties and achieved a large weight reduction compared to Comparative Examples 1 and 3.

Sensory test

Similar to the evaluation performed using finger surface temperature, a packaging bag containing tap water was manufactured and left in a -18 ° C freezer for 24 hours (for an entire day and night ). Subsequently, the packaging bag was taken out of the freezer and held by five evaluators to evaluate the heat-insulating properties. More particularly, it was rated as "1" when the rater felt cold, while it was rated as "3" if the cold was not easily felt. Consequently, the evaluation was carried out in three stages between 1 and 3. The results of the evaluation are shown in Table 2.

Table 2

<td>Evaluation</td><td>Example 1</td><td>Example 2</td><td>Comparative Example 1</td><td>Comparative Example 2</td><td>Comparative Example 3</td>

<td> 1</td><td>Zero</td><td>Zero</td><td>Zero</td><td>Five</td><td>Zero</td>

<td> 2</td><td>One</td><td>Zero</td><td>Four</td><td>Zero</td><td>Two</td>

<td> 3</td><td>Four</td><td>Five</td><td>One</td><td>Zero</td><td>Three</td>

<td>Total score</td><td> 14</td><td> 15</td><td> 11</td><td> 5</td><td> 13</td>

The packaging bag manufactured using the heat insulating packaging film having an open cell layer in each of Examples 1 and 2 exhibited excellent heat insulating properties.

Meanwhile, the packaging bag manufactured using the heat insulating packaging film having a closed cell layer as the heat insulating layer in Comparative Example 1 had insufficient heat insulating properties.

The packaging bag manufactured using the packaging film without a heat-insulating layer in Comparative Example 2 had almost no heat-insulating properties.

The packaging bag manufactured using the packaging film in Comparative Example 3 had heat-insulating properties substantially the same as in Example 1. However, since the actual thickness of the resin in the foamed layer was 3 times or more than that of the example 1, the thermal insulation efficiency was considerably lower than that of Example 1.

That is, Examples 1 and 2 exhibited superior heat insulation properties and achieved a large weight reduction compared to Comparative Examples 1 and 3.

Industrial applicability

The heat-insulating packaging film, the packaging bag and the packaging bag having a nozzle according to the present invention can achieve sufficiently high heat-insulating properties.

Description of reference numbers

1: packaging bag with opening member (nozzle)

2: packaging bag

3: opening member (mouthpiece)

10: heat insulating packaging film

11: base material

12: open cell layer

13: sealing layer