JP7029250B2 - How to use the packaging container and the packaging container - Google Patents

Description

The present invention relates to, for example, a packaging container for accommodating high-temperature food heated in a microwave oven and a method of using the packaging container, and more specifically, a packaging in which a laminated film having at least heat resistance and oil resistance is laminated. Concerning how to use containers for food and packaging.

Traditionally, for example, foods sold in supermarkets and convenience stores have been stored and sold in thermoplastic resin packaging containers. At this time, the type of packaging container has been selected according to the type of food. For example, a packaging container for storing cooked food that is heated in a microwave oven or the like has heat resistance that does not deform even at high temperatures, oil resistance that does not allow oil from heated food to penetrate, and also has a printing layer. A laminated structure with easy-to-see beauty has been adopted.

For example, it is a laminated foamed sheet in which a polypropylene-based resin printing film composed of a polypropylene-based resin layer and a printing layer is laminated on a polypropylene-based resin foamed sheet by a thermal lamination method so that the printed layer is on the inside (foamed sheet surface side). The idea of preventing the film layer from swelling during heat molding by having the peel strength between the film and the foamed sheet of 1.5 N / 25 mm or more is disclosed (see Patent Document 1).

In addition, the polybutylene terephthalate resin sheet, which is the base material of the composite sheet, has excellent heat resistance compared to polystyrene resin and the like, and the polybutylene terephthalate resin film laminated on this to form the inner surface of the container is compared with polypropylene resin. The idea of excellent heat resistance, excellent oil resistance at high temperatures, and good thermoformability is disclosed (see Patent Document 2).

Further, one of the conditions is that the polybutylene terephthalate film layer is formed from a laminated body in which a polybutylene terephthalate layer is laminated on at least one surface of the base layer, and the thickness ratio of the polybutylene terephthalate film layer to the base layer is 1: 0.03 to 0.15. , The idea of a container having excellent transparency, moldability, impact resistance, and gas barrier property is disclosed (see Patent Document 3).

Further, by one of the conditions that the tensile breaking strength in four directions is 50% or more and 150% or less, biaxially stretched polybutylene terephthalate having less anisotropy and excellent dimensional stability and impact resistance ( The idea of a PBT) film having a thickness of 5 to 50 μm when used as a general converting film, being printed and used, and being used as a base material for food packaging is disclosed. (See Patent Document 4).

Japanese Patent Application Laid-Open No. 2003-300921 Published Utility Model Hei 4-13344 Gazette Published Utility Model Hei 4-52047 Gazette Japanese Unexamined Patent Publication No. 2012-121241

However, the above-mentioned conventional technique may not be compatible with foods for heating in recent microwave ovens and the like. That is, when food is heated in a microwave oven, food-derived oil and cooking oil also reach a high temperature and flow out, so that they permeate and stay in the adhesive portion between the layers from the surface layer of the packaging container. The phenomenon that each layer is peeled off (hereinafter, also referred to as "derami phenomenon") is likely to occur. Therefore, in order to prevent the delamination phenomenon, the surface layer of the packaging container should be composed of at least a thermoplastic resin having a large difference from the solubility parameter of the oil, and even if the oil permeates the surface layer. The laminated film should be constructed with a thickness that does not penetrate until the adhesive portion between the layers is peeled off.

Further, when the laminating film having the above-mentioned characteristics includes a print layer, it is necessary that the printed content is easy to see even through the surface layer. That is, the surface layer is evenly stretched on the packaging container molded into a predetermined shape to prevent wrinkles and uneven thickness to ensure transparency, and the printed layer is made to follow the surface layer. You should avoid the risk that the printed content will be stretched.

Further, it is necessary that the laminated film having the above-mentioned characteristics does not shrink too much regardless of the temperature rise due to heating of a microwave oven or the like, and each layer does not peel off regardless of the shape of the packaging container to be molded. That is, it is necessary to avoid the possibility that the laminated film shrinks and breaks depending on the heating temperature, or that the peeling between the layers that cannot withstand the complicated shape of the packaging container causes molding defects.

Further, it is necessary that the base material on which the laminating film having the above-mentioned characteristics is laminated does not deform regardless of the temperature rise due to heating of a microwave oven or the like. That is, considering the heat shrinkage of the laminated film that realizes the moldability of the packaging container and the adhesive strength with the laminated film, the base material itself should have a structure that can withstand heating.

Therefore, an object of the present invention is to make a laminated film which is less likely to cause a delamination phenomenon due to high-temperature oil generated from food heated in a microwave oven, the printed layer is easy to see, and can be molded regardless of the shape, and the above-mentioned laminate. It is an object of the present invention to provide a packaging container made of a base material having a heat-resistant structure that promotes the characteristics of a film, and a method of using the packaging container.

The packaging container according to the present invention is a packaging container in which a heat-resistant base material is laminated on the outermost layer and a non-foamed laminate film is laminated on the innermost layer, and the heat-resistant base material has a foam layer. The non-foamed laminated film may be characterized by having at least one layer or more of a thermoplastic resin layer, the SP value of the thermoplastic resin layer is 9.0 or more, and the thickness is 10 to 30 μm.

Further, it is desirable that the thermoplastic resin layer is made of a polyester resin.

Further, it is desirable that the thermoplastic resin layer is formed of a polybutylene terephthalate resin.

Further, it is desirable that the thermoplastic resin layer is biaxially stretched.

Further, it is desirable that the tensile elongation at break of the thermoplastic resin layer is 100% or more.

Further, it is desirable that the heat shrinkage rate of the thermoplastic resin layer at 150 ° C. is 3.0% or less.

Further, it is desirable that the peel strength of the non-foamed laminated film with respect to the heat-resistant substrate is 3.0 N / 15 mm or more.

Further, it is desirable that the heat-resistant substrate has a non-foamed surface layer laminated on at least one surface of the foamed layer.

Further, it is desirable that the heat-resistant substrate has a non-foaming intermediate layer laminated on at least one surface of the foaming layer and a non-foaming surface layer laminated on the outside of the non-foaming intermediate layer.

Further, in the method of using the packaging container according to the present invention, the oily food may be placed in the packaging container having the above-mentioned characteristics and heated in a microwave oven.

The definition, meaning, specific example, reason, etc. of each requirement constituting the present invention are shown below.

The "outermost layer" may mean the outermost layer (the layer closest to the outside air) of the molded packaging container. The "innermost layer" may mean the innermost layer [the layer closest to (or in contact with) the food contained in the container] of the packaging container.

The "heat-resistant base material" is a simple material that forms the outermost layer of a packaging container and has heat resistance when heated (for example, 1900w) in a microwave oven, impact resistance from the outside, and stacking suitability with a printing layer. A thermoplastic resin sheet having a layer or a plurality of layers (for example, "foam layer", "non-foam surface layer", "non-foam intermediate layer", etc.) may be applicable.

The "foam layer" may correspond to one of the "heat-resistant base material" itself or a plurality of layers constituting the "heat-resistant base material". When the "foaming layer" is one layer of the plurality of layers, the other layer may correspond to a "non-foaming surface layer" or a "non-foaming intermediate layer" laminated on at least one surface of the "foaming layer". The "foam layer" may be composed of a plurality of foam layers having different bubble diameters. The "non-foamed surface layer" is a layer of the surface of the "heat-resistant substrate" before being laminated with the "non-foamed laminated film" (the outermost layer at the time of molding and / or a layer in contact with the "non-foamed laminated film". ), And may be laminated on one side or both sides of the "foam layer".
The "non-foaming intermediate layer" may correspond to an intermediate layer interposed between the "non-foaming surface layer" and the "foaming layer", or may be laminated on one side or both sides of the "foaming layer". ..

The thermoplastic resin constituting the "foamed layer", "non-foamed surface layer", or "non-foamed intermediate layer" laminated as the "heat-resistant base material" is, for example, a polyester resin, a polystyrene resin, or a polycarbonate resin. , A polyolefin resin is contained, preferably a polyolefin resin, more preferably a polypropylene resin, and a mixture of a polypropylene resin and a polyethylene resin may be used, or an inorganic filler (talc) may be contained.
The above-mentioned "non-foaming surface layer" and "non-foaming intermediate layer" have the advantages of suppressing foreign substances (such as eyebrows) and odors emitted by the "foaming layer" containing talc, and preventing molding defects. be.

The "non-foamed laminated film" forms the innermost layer of a packaging container, and has heat resistance and oil resistance when heated by a microwave oven (for example, 1900 W) or when in contact with high-temperature (100 to 150 ° C.) foods. A non-foamed thermoplastic resin film having a single layer or a plurality of layers (for example, a predetermined thermoplastic resin layer, a printing layer, etc.) having a stackability with a printing layer, a gas barrier property, and the like may be applicable.

The thermoplastic resin constituting the predetermined thermoplastic resin layer laminated as the "non-foamed laminate film" contains at least a polyester resin, preferably a polybutylene terephthalate resin, and two polybutylene terephthalate resins. It is still preferable that the shaft is stretched. This is because polybutylene terephthalate is excellent not only in heat resistance that is not easily deformed by temperature changes, but also in shrinkage resistance, bending resistance, impact resistance, wear resistance, etc. This is because improvement in transparency and printing pitch can be expected.

The solubility parameter (SP value) of the thermoplastic resin layer constituting the "non-foamed laminated film" is preferably 9.0 or more, and if it is less than 9.0, the thickness (10 to 30 μm) of the thermoplastic resin layer and the peel strength (3). .0N / 15mm or more) and / or due to the relationship with heat resistant temperature (100 to 150 ° C), etc., the oil generated by the food itself and the components of the oil during cooking (for cooking and seasoning) (and their temperature rise) Along with this, the oil permeates the thermoplastic resin layer and causes a chemical reaction at the bonded portion between the "heat-resistant base material" and the "non-foaming laminate film" to cause a chemical reaction between the "heat-resistant base material" and the "non-foaming laminate film". This is because there is a risk of inducing a phenomenon (derami phenomenon) in which the resin layer is inserted between the "" and / or each of the thermoplastic resin layers constituting the "non-foamed laminated film".
The "heat-resistant substrate" and the "non-foamed laminated film" may be bonded by, for example, thermocompression bonding, dry laminating, extrusion laminating, coating agent, or the like.

In terms of suppressing the delamination phenomenon described above, the thickness of the thermoplastic resin layer may be 10 to 30 μm, preferably 12 to 25 μm, more preferably 15 to 20 μm, and if it is less than 10 μm, the thickness is thin and the oil permeates. If it exceeds 30 μm, the cost of raw materials may increase and the visibility of the printed layer may decrease.

The tensile elongation at break of the thermoplastic resin layer constituting the "non-foamed laminated film" may be 100% or more, preferably 120 or more%, more preferably 150% or more, and if it is less than 100%, packaging having a complicated shape. There is a risk that the container will not stretch sufficiently and cracks or breaks will occur. Therefore, regardless of the shape of the packaging container, it is desirable to have a tensile elongation at break that can be used for drawing molding and the like.

If the thermal shrinkage of the thermoplastic resin layer constituting the "non-foaming laminated film" for food heated to 150 ° C. by heating is 3.0% or less, the deformation of the packaging container due to shrinkage can be suppressed, but 3.0. This is because if it exceeds%, even the "heat-resistant base material" of the packaging container may be deformed.

The peel strength of the "non-foamed laminated film" with respect to the "heat-resistant substrate" is preferably 3.0 N / 15 mm or more, and if it is less than 3.0 N / 15 mm, the non-foamed laminated film has poor followability during molding and the laminated film is peeled off. And may lead to molding defects.

The glossiness (gloss value) of the thermoplastic resin layer constituting the "non-foamed laminated film" may be 100% or more, preferably 110% or more, more preferably 120% or more, and is the above-mentioned thermoplastic resin layer. In relation to the SP value and the thickness, if it is less than 100%, not only the gloss and the like are insufficient and the appearance of the innermost layer is deteriorated, but also the visibility of the printed layer may be deteriorated.

The drawing ratio calculated from the relationship between the depth and the diameter of the packaging container in which the above-mentioned "heat-resistant substrate" and "non-foamed laminated film" are laminated may be 0.01 to 1.0, preferably 0. It may be 0.03 to 0.8, more preferably 0.05 to 0.6, and if it is more than 1.0, it is non-foamed after molding in relation to the thickness, peeling strength and heat shrinkage of the above-mentioned thermoplastic resin layer. The laminated film may become thin and may not exhibit sufficient performance.

In the packaging container according to the present invention, the SP value of the thermoplastic resin layer constituting the non-foamed laminate film laminated on the heat-resistant substrate is 9.0 or more, and the thickness is 10 to 30 μm, so that a microwave oven or the like can be used. Even if it is heated in, the oil generated from the food does not easily penetrate the thermoplastic resin layer, and the oil does not enter between the non-foamed laminate film and the heat-resistant base material and does not stay, so that the occurrence of the delamination phenomenon can be prevented. can. That is, due to the combination of the SP value and the thickness of the thermoplastic resin layer described above, the oil does not penetrate (or completely penetrates) the non-foamed laminate film and does not reach the bonded portion with the heat-resistant substrate (even if it reaches). Since it does not affect the quality of the packaging container, it can be expected to improve the quality.

Further, a polyester resin is adopted as the thermoplastic resin layer, the polyester resin is a polybutylene terephthalate resin, and the polybutylene terephthalate resin is biaxially stretched. When the tensile elongation at break of the thermoplastic resin layer is 100% or more, not only the above-mentioned characteristics can be expected to be provided in the non-foamed laminated film and the delamination phenomenon can be suppressed more effectively, but also the printing layer is beautiful. It is possible to improve the sex. That is, the visibility of the print layer is improved along with the improvement of transparency and print pitchability due to the biaxial stretching of the thermoplastic resin layer, and the print layer is stretched by having a desired tensile elongation at break. Since unevenness can be suppressed, the effect of expressing the contents of the laminated print layers in a desired state even after molding can be expected.

Further, the tensile elongation at break of the thermoplastic resin layer is 100% or more, the heat shrinkage at 150 ° C. is 3.0% or less, and the peel strength of the non-foamed laminate film with respect to the heat-resistant substrate is 3. When it is 0 N / 15 mm or more, not only the delamination phenomenon can be suppressed and the print beauty can be improved, but also the moldability can be improved. That is, in addition to the desired tensile elongation at break, the shrinkage rate can be suppressed with respect to the temperature of food heated in a microwave oven (about 150 ° C.), and the peel strength can withstand various moldings. , The effect of being able to mold into a desired state even with a complicated shape can be expected.

Further, by laminating the non-foaming surface layers 12 and 12 (or the non-foaming surface layers 12 and 12 on the outside of the non-foaming intermediate layers 13 and 13) on at least one surface of the heat-resistant base material 1, the rigidity and surface surface are increased. Along with smoothness, heat resistance can be improved.

It is a front view which shows an example of the packaging container of this invention. It is a partially enlarged end view of the said packaging container. It is a conceptual diagram which shows the use state of the said packaging container.

Hereinafter, the outline of the packaging container (hereinafter, also referred to as “packaging container”) according to the present embodiment will be described with reference to FIGS. 1 and 2.

As shown in FIGS. 1 and 2, the present packaging container is a packaging container P in which a heat-resistant base material 1 is laminated on the outermost layer and a non-foamed laminated film 2 is laminated on the innermost layer, and the heat-resistant container P is formed. The sex substrate has a foamed layer 11, and this non-foamed laminated film has at least one or more thermoplastic resin layers 21, the SP value of the thermoplastic resin layer is 9.0 or more, and the thickness is 10. It may be up to 30 μm.

Here, the thermoplastic resin layer 21 is made of a polyester resin, and among them, a polybutylene terephthalate resin is preferable, and it is more preferable that the polybutylene terephthalate resin is biaxially stretched.

Further, the tensile elongation at break of the thermoplastic resin layer 21 is 100% or more, the heat shrinkage at 150 ° C. is 3.0% or less, and the peel strength of the non-foamed laminated film 2 with respect to the heat-resistant substrate 1 is 3.0 N / 15 mm. The above is preferable.

Further, the heat-resistant substrate 1 is formed by a non-foaming surface layer 12 laminated on at least one surface of the foaming layer 11, or a non-foaming intermediate layer 13 and a non-foaming surface layer 12 laminated on the outside of the non-foaming intermediate layer. It may be configured.

Next, the heat-resistant base material and the non-foamed laminated film constituting the packaging container will be described in detail.
For parts that cannot be confirmed and cannot be seen on the drawings, some parts and leader lines are indicated by broken lines. For the parts that are virtually depicted on the drawing, some parts and leader lines are shown by two-dot chain lines.

The heat-resistant base material 1 shown in FIGS. 1 and 2 is made of a polypropylene-based resin, and is further mixed with a foaming agent to form a foam layer 11 and a non-foamed intermediate layer 13 laminated on both sides of the foamed layer. And the non-foaming surface layer 12 laminated on both sides of the non-foaming intermediate layer may be composed of. One of the non-foaming surface layers 12 may correspond to the outermost layer (outside air contact surface) of the packaging container, and one of the non-foaming intermediate layers 13 may correspond to the contact surface with the non-foaming laminate film 2. Each layer may contain an inorganic filler (talc). The thickness of the foamed layer 11 may be 300 to 1500 μm, the thickness of the non-foamed surface layer may be 1 to 20 μm, and the thickness of the non-foamed intermediate layer may be 50 to 300 μm.

According to this configuration, the non-foamed surface layer 12 and the non-foamed intermediate layer 13 improve the heat resistance performance as well as the rigidity and surface smoothness of the packaging container P, and the foreign matter (mayani) generated by the foamed layer 11 containing talc. Etc.), odor can be suppressed, and molding defects can be prevented.
The non-foamed intermediate layer 13 may not be provided on both sides of the foamed layer 11, and only the non-foamed surface layer 12 may be laminated. Further, the heat-resistant base material 1 is made of a heat-resistant material (heat-resistant PSP, heat-resistant foam PET, etc.) without any distinction between the foam layer 11, the non-foam surface layer 12, and the non-foam intermediate layer 13. It may be a single layer.

The non-foamed laminate film 2 shown in FIGS. 1 and 2 has a thermoplastic resin layer 21 made of a polyester resin (preferably a biaxially stretched polybutylene terephthalate resin) and a surface facing the thermoplastic resin layer. The printed layer 22 may be composed of the heat-resistant base material 1 and the dry lami adhesive layer 23 adhered when the non-foamed laminated film is bonded by the dry laminating method. The thermoplastic resin layer 21 corresponds to the innermost layer (food contact surface) of the main packaging container, and the printing layer 22 may be located between the thermoplastic resin layer 21 and the dry Lami adhesive layer 23.

The thermoplastic resin layer 21 has an SP value of 9.0 or more (for example, 10.0), a thickness of 10 to 30 μm (further, 12 to 25 μm), a tensile elongation at break of 100% or more, and heat shrinkage at 150 ° C. The rate may be 3.0% or less.
The peel strength of the non-foamed laminated film 2 with respect to the heat-resistant substrate 1 may be 3.0 N / 15 mm or more.

According to this configuration, by making the thermoplastic resin layer 21 having the above-mentioned numerical characteristics the innermost layer, it is possible to prevent the oil or the like of food from permeating into the printing layer 22 or the dry laminating adhesive layer 23 of the lower layer. can. Further, since the thermoplastic resin layer 21 is biaxially stretched and the print layer 22 is adjacent to the innermost layer, the printed contents can be easily seen through the thermoplastic resin layer. Further, the thermoplastic resin layer 21 does not easily shrink even when heated in a microwave oven or the like, and the heat-resistant base material 1 and the non-foamed laminated film 2 do not peel off even when molded into a complicated shape, and maintain a desired state. be able to.
In addition, a thermoplastic resin layer other than the thermoplastic resin layer 21 (for example, a polypropylene resin layer or the like) may be laminated. The thermoplastic resin layer 21 may be unstretched, uniaxially stretched, or biaxially stretched. The thermoplastic resin layer 21 and the printing layer 22 may be adjacent to each other via a dry laminating adhesive layer by a dry laminating method. The heat-resistant base material 1 and the non-foamed laminated film 2 may be adhered to each other with a coating agent.

Here, an outline of the present packaging container and an example of the usage state will be described with reference to FIGS. 1 to 3.

As shown in FIGS. 1 and 3, the main packaging container (hereinafter, also referred to as “packaging container P”) is not particularly limited as long as it has a shape capable of storing the oily food F, and for example, this food can be placed on it. The bottom part (not numbered) to be placed, the side wall part (not numbered) erected diagonally upward from this bottom part, and the flange part extending outward from the upper end of this side wall part (not numbered). The opening portion may be closed with a predetermined lid (a film-shaped top seal, an inner fitting type or an outer fitting type molded lid, etc.).

When the food F is heated in a microwave oven, the oil generated by the food itself and the oil during cooking (cooking and seasonings) are liquefied to increase the fluidity. It tries to penetrate the lower layer from the contact part (innermost layer) with. At this time, as shown in FIG. 2, the thermoplastic resin layer 21 of the non-foamed laminated film 2 corresponding to the innermost layer allows these oils to permeate (or completely permeate) the printing layer 22 and the dry laminating adhesive layer 23. Prevents (peeling off the dry laminate adhesive layer). Therefore, it is possible to avoid the delamination phenomenon in which the oil content of food or the like in a high temperature state enters between the heat-resistant base material 1 and the non-foaming laminated film 2.

Here, an evaluation test (hereinafter, also referred to as “this evaluation test”) for a packaging container molded under the conditions of the examples and comparative examples listed below will be described.

First, a test method for a packaging container molded according to the items of this evaluation test, Examples and Comparative Examples will be described.

The items of this evaluation test are the heat resistance of the packaging container (presence or absence of deformation of the container), the presence or absence of the delamination phenomenon, the shapeability by molding, the beauty of the printed layer, and the cost.
In this evaluation test, vacuum forming is adopted as the molding method of the packaging container, and the state of the packaging container after storing the heating curry in the molded packaging container and heating it in a microwave oven with a 1900 W output for 1 minute. Shall be visually observed.

Next, the test conditions of Examples 1 to 11 are listed below.

<< Example 1 >>
(Laminate film)
Layer structure: (from the innermost layer side) biaxially stretched polybutylene terephthalate layer (OPBT, thickness 15 μm, SP value 10.0, tensile elongation at break 100% or more, heat shrinkage rate 3.0% or less), printing layer, dry laminating Adhesive film thickness total: 15 μm
(Base material)
Layer structure: Surface layer [polypropylene (PP), thickness 10 μm], intermediate layer [polypropylene (PP + talc), thickness 150 μm], foam layer [polypropylene (PP + foaming agent), thickness 800 μm], intermediate layer (from the outermost layer side) (Same as above), Surface layer (Same as above)
(Adhesive strength between the laminated film and the base material)
3.0N / 15mm or more

<< Example 2 >>
(Laminate film)
Layer structure: (from the innermost layer side) biaxially stretched polybutylene terephthalate layer (OPBT, thickness 15 μm, SP value 10.0, tensile elongation at break 100% or more, heat shrinkage rate 3.0% or less), printing layer, dry laminating Adhesive, unstretched polypropylene layer (CPP, thickness 25 μm), coating agent Total film thickness: 40 μm
(Base material)
Same as Example 1 (adhesive strength between the laminated film and the base material)
Same as Example 1

<< Example 3 >>
(Laminate film)
Layer structure: (from the innermost layer side) biaxially stretched polybutylene terephthalate layer (OPBT, thickness 15 μm, SP value 10.0, tensile elongation at break 100% or more, heat shrinkage rate 3.0% or less), dry lami adhesive, Printing layer, unstretched polypropylene layer (CPP, thickness 25 μm), coating agent Total film thickness: 40 μm
(Base material)
Same as Example 1 (adhesive strength between the laminated film and the base material)
Same as Example 1

<< Example 4 >>
(Laminate film)
Same as Example 1 (base material)
Layer structure: (from the outermost layer side) surface layer [polypropylene layer (PP), thickness 10 μm], foam layer [polypropylene layer (PP + foaming agent), thickness 1000 μm], surface layer (same as above)
(Adhesive strength between the laminated film and the base material)
Same as Example 1

<< Example 5 >>
(Laminate film)
Layer structure: (from the innermost layer side) biaxially stretched polybutylene terephthalate layer (OPBT, thickness 15 μm, SP value 10.0, tensile elongation at break 100% or more, heat shrinkage rate 3.0% or less), printing layer, dry laminating Adhesive, polystyrene layer (CPS, thickness 20 μm)
Total film thickness: 30 μm
(Base material)
Layer structure: Surface layer [polystyrene paper (PSP), thickness 3000 μm]
(Adhesive strength between the laminated film and the base material)
Same as Example 1

<< Example 6 >>
(Laminate film)
Layer structure: (from the innermost layer side) polybutylene terephthalate layer (PBT, thickness 15 μm, SP value 10.0, tensile elongation at break 100% or more, heat shrinkage rate 3.0% or less), printing layer, dry lami adhesive, Polystyrene layer (CPS, thickness 20 μm)
Total film thickness: 15 μm
(Base material)
Same as Example 1 (adhesive strength between the laminated film and the base material)
Same as Example 1

<< Example 7 >>
(Laminate film)
Layer structure: (from the innermost layer side) biaxially stretched polybutylene terephthalate layer (OPBT, thickness 15 μm, SP value 10.0, tensile elongation at break 50%, heat shrinkage rate 3.0% or less), printing layer, dry laminating adhesion Total film thickness: 15 μm
(Base material)
Same as Example 1 (adhesive strength between the laminated film and the base material)
Same as Example 1

<< Example 8 >>
(Laminate film)
Layer structure: (from the innermost layer side) biaxially stretched polybutylene terephthalate layer (OPBT, thickness 15 μm, SP value 10.0, tensile elongation at break 50% or more, heat shrinkage 5.0%), printing layer, dry laminating adhesion Total film thickness: 15 μm
(Base material)
Same as Example 1 (adhesive strength between the laminated film and the base material)
Same as Example 1

<< Example 9 >>
(Laminate film)
Layer structure: (from the innermost layer side) biaxially stretched polybutylene terephthalate layer (OPBT, thickness 12 μm, SP value 10.0, tensile elongation at break 50% or more, heat shrinkage rate 3.0% or less), printing layer, dry laminating Adhesive film thickness total: 12 μm
(Base material)
Same as Example 1 (adhesive strength between the laminated film and the base material)
Same as Example 1

<< Example 10 >>
(Laminate film)
Layer structure: (from the innermost layer side) biaxially stretched polybutylene terephthalate layer (OPBT, thickness 25 μm, SP value 10.0, tensile elongation at break 50% or more, heat shrinkage rate 3.0% or less), printing layer, dry laminating Adhesive film thickness total: 25 μm
(Base material)
Same as Example 1 (adhesive strength between the laminated film and the base material)
Same as Example 1

<< Example 11 >>
(Laminate film)
Layer structure: (from the innermost layer side) biaxially stretched polybutylene terephthalate layer (OPBT, thickness 15 μm, SP value 10.0, tensile elongation at break 50% or more, heat shrinkage rate 3.0% or less), printing layer, dry laminating Adhesive film thickness total: 15 μm
(Base material)
Same as Example 1 (adhesive strength between the laminated film and the base material)
Less than 1.0N / 15mm

Next, the test conditions of Comparative Examples 1 to 3 are listed below.

<< Comparative Example 1 >>
(Laminate film)
Layer structure: (from the innermost layer side) biaxially stretched polybutylene terephthalate layer (OPBT, thickness 8 μm, SP value 10.0, tensile elongation at break 50% or more, heat shrinkage rate 3.0% or less), printing layer, dry laminating Adhesive film thickness total: 8 μm
(Base material)
Layer structure: Surface layer [polypropylene (PP), thickness 10 μm], intermediate layer [polypropylene (PP + talc), thickness 150 μm], foam layer [polypropylene (PP + foaming agent), thickness 800 μm], intermediate layer (from the outermost layer side) (Same as above), Surface layer (Same as above)
(Adhesive strength between the laminated film and the base material)
3.0N / 15mm or more

<< Comparative Example 2 >>
(Laminate film)
Layer structure: (from the innermost layer side) biaxially stretched polybutylene terephthalate layer (OPBT, thickness 40 μm, SP value 10.0, tensile elongation at break 50% or more, heat shrinkage rate 3.0% or less), printing layer, dry laminating Adhesive film thickness total: 40 μm
(Base material)
Same as Comparative Example 1 (Adhesive strength between laminated film and base material)
Same as Comparative Example 1

<< Comparative Example 3 >>
(Laminate film)
Layer structure: (from the innermost layer side) unstretched polypropylene layer (CPP, thickness 25 μm, SP value 7.5, tensile elongation at break 50% or more, heat shrinkage 3.0% or less), printing layer, dry lami adhesive film Total thickness: 40 μm
(Base material)
Same as Comparative Example 1 (Adhesive strength between laminated film and base material)
Same as Comparative Example 1

Next, the differences in the test conditions of the above-mentioned Examples and Comparative Examples will be described.

<< Differences in test conditions of Examples 1 to 3 >>
The difference between Examples 1 and Examples 2 and 3 is the layer structure of the non-foamed laminated film. Example 1 does not have a polypropylene layer, and Examples 2 and 3 have a polypropylene layer.
The difference between Examples 2 and 3 is the position of the printed layer, which is adjacent to the biaxially stretched polybutylene terephthalate layer in Example 2 and adjacent to the biaxially stretched polybutylene terephthalate layer in Example 3. do not have.

<< Differences in test conditions of Examples 1, 4, and 5 >>
The difference between Examples 1 and Examples 4 and 5 is the layer structure of the heat-resistant base material. In Example 1, there is an intermediate layer, but in Examples 4 and 5, there is no intermediate layer.
The difference between Examples 4 and 5 is the type of material constituting the heat-resistant base material. In Example 4, polypropylene is the main component, and in Example 5, polystyrene paper is the main component.

<< Differences in test conditions of Examples 1 and 6 to 10 >>
The difference between Examples 1 and Examples 6 to 10 is the characteristics of the non-foamed laminated film. In Example 6, polybutylene terephthalate not biaxially stretched was adopted for Example 1, and Example 7 was adopted. The tensile elongation at break was 50%, the heat shrinkage at 150 ° C. was 5.0% in Example 8, and the thickness of the biaxially stretched polybutylene terephthalate layer was 12 μm in Example 9. In No. 10, the thickness of the biaxially stretched polybutylene terephthalate layer is 25 μm.

<< Differences in test conditions of Examples 1 and 11 >>
The difference between Example 1 and Example 11 is the adhesive strength between the non-foamed laminated film and the base material, which is less than 1.0 N / 15 mm in Example 11 with respect to Example 1.

<< Differences in test conditions between Example 1 and Comparative Examples 1 to 3 >>
The difference between Example 1 and Comparative Examples 1 and 2 is the thickness of the biaxially stretched polybutylene terephthalate layer, which is 8 μm in Comparative Example 1 and 40 μm in Comparative Example 2 with respect to Example 1.
The difference between Example 1 and Comparative Example 3 is the type of thermoplastic resin constituting the innermost layer, and in Comparative Example 3, unstretched polypropylene (SP value 7.5) was adopted as opposed to Example 1. There is.

≪Test results≫
Here, Table 1 shows the test results in Examples 1 to 11 and Comparative Examples 1 to 3 in consideration of the differences from Example 1 described above. For convenience of reference, the table also lists the test conditions described above.
The "adhesive strength" may include not only between the non-foamed laminated film and the base material, but also other layers including between the predetermined thermoplastic resin layer and the printing layer.

The indicators for each evaluation item are as follows.
Heat resistance: 〇 (no deformation), △ (may be deformed), × (may be deformed)
Presence / absence of delamination: 〇 (none), △ (somewhat afraid), × (afraid)
Shape by molding: 〇 (good), △ (slightly defective), × (defective)
Print beauty: 〇 (easy to see), △ (slightly hard to see), × (hard to see)
Cost: 〇 (reasonable), △ (slightly expensive), × (expensive)
Comprehensive evaluation: ◎ (no problem), 〇 (generally no problem), × (problem)

In Example 1, no deformation of the packaging container due to heating was observed (heat resistance: 〇), food oil did not permeate the non-foamed laminate film, and did not stay between the heat-resistant substrate and between the layers (heat resistance: 〇). With or without delamination: 〇), the non-foamed laminate can be molded into the desired shape and state according to the molding die (formability by molding: 〇), and the state of the printed layer can be visually checked from the innermost layer of the packaging container. It was clearly confirmed (printing beauty: 〇), the raw material cost was reasonable (cost: 〇), and there was no problem as a packaging container (comprehensive evaluation: ◎).

In Examples 2 and 3, the raw material cost may be slightly increased due to the presence of the polypropylene layer (cost property: Δ), but the other evaluation items are good (〇), and the differences between Examples 2 and 3 (0). There was no particular problem as a packaging container without any influence due to the position of the printing layer) (Comprehensive evaluation: 〇).

In Examples 4 and 5, since there is no intermediate layer or surface layer of the heat-resistant base material, the packaging container is fragile and may be slightly deformed (heat resistance: Δ), but other evaluation items are It was good (〇), there was no influence due to the difference between Examples 4 and 5 (type of material of heat-resistant base material), and there was no particular problem as a packaging container (comprehensive evaluation: 〇).

Of Examples 6 to 10, since the polybutylene terephthalate is not biaxially stretched in Example 6, uneven expansion and contraction may occur everywhere after molding, and the state of the printed layer may look slightly unclear (printing beauty: Δ), the shape may be limited because the tensile elongation at break is small in Example 7 and cannot follow the molding die (formability due to molding: Δ), and in Example 8, the temperature is 150 ° C. Since the heat shrinkage rate is high, there is a risk that the packaging container will be slightly deformed due to shrinkage due to the heating temperature and heated oil (heat resistance: Δ), and in Example 9, biaxially stretched polybutylene terephthalate. Since the layer is thin, there is a risk that food oil will permeate and reach the heat-resistant substrate and stay a little (presence or absence of delamination: △), and the shape may be limited because it cannot follow the molding die. Yes (formability by molding: △), there is a risk that the raw material cost will increase a little because the biaxially stretched polybutylene terephthalate layer is thicker in Example 10 (cost property: △), but in each example The evaluation items other than the above points were good (〇), and there was no particular problem as a packaging container (comprehensive evaluation: 〇).

In Example 11, since the adhesive strength between the non-foamed laminated film and the base material is low, the shape may be limited because it cannot follow the molding die due to peeling (formability by molding: Δ). The other evaluation items were good (〇), and there was no particular problem as a packaging container (comprehensive evaluation: 〇).

In Comparative Example 1, since the biaxially stretched polybutylene terephthalate layer is thin, food oil may permeate and reach the heat-resistant substrate and stay there (with or without delamination: ×), and follow the molding die. It was judged that there was a problem as a packaging container (comprehensive evaluation: x) because it could not be completely broken and there was a risk of breakage (formability due to molding: x).
On the other hand, in Comparative Example 2, since the biaxially stretched polybutylene terephthalate layer is thick and the raw material cost may increase (cost: Δ), it was judged that there is a problem as a packaging container (comprehensive evaluation:). ×).
Further, in Comparative Example 3, since the innermost layer is unstretched polypropylene, it is close to the SP value of the food oil, and the oil may permeate and reach the heat-resistant substrate and stay there (presence / absence of delamination: ×). ), It was judged that there was a problem as a packaging container (comprehensive evaluation: ×).

Hereinafter, the effects of the present packaging container will be described with reference to FIGS. 1 to 3 based on the above-described embodiments and examples.

In this packaging container, the SP value of the thermoplastic resin layer 21 constituting the non-foamed laminate film 2 laminated on the heat-resistant base material 1 is 9.0 or more, and the thickness is 10 to 30 μm, so that the microwave oven is used. Even if it is heated by such as, the oil generated from the food F does not easily permeate the thermoplastic resin layer, and the oil does not enter between the non-foamed laminate film and the heat-resistant base material and does not stay, so that the delamination phenomenon occurs. Can be prevented. That is, due to the combination of the SP value and the thickness of the thermoplastic resin layer 22, the oil does not permeate (or completely permeate) the non-foamed laminate film 2 and does not reach the bonded portion with the heat-resistant base material 1. However, the quality of the packaging container P can be expected to improve.

Further, a polyester resin is adopted as the thermoplastic resin layer 21, the polyester resin is a polybutylene terephthalate resin, and the polybutylene terephthalate resin is biaxially stretched. When the tensile elongation at break of the thermoplastic resin layer is 100% or more, not only the above-mentioned characteristics can be expected to be provided in the non-foamed laminate film 2 to more effectively suppress the delamination phenomenon, but also the printing layer 2 can be expected. It is possible to improve the beauty of the plastic. That is, the visibility of the print layer 22 is improved along with the improvement of transparency and print pitchability due to the biaxial stretching of the thermoplastic resin layer 21, and the print layer has a desired tensile elongation at break. Since uneven elongation can be suppressed, the effect of expressing the contents of the laminated printed layers in a desired state even after molding can be expected.

Further, the tensile elongation at break of the thermoplastic resin layer 21 is 100% or more, the heat shrinkage rate at 150 ° C. is 3.0% or less, and the peel strength of the non-foamed laminate film 2 with respect to the heat-resistant substrate 1 is 3. When it is 0 N / 15 mm or more, not only the delamination phenomenon can be suppressed and the print beauty can be improved, but also the moldability can be improved. That is, in addition to the desired tensile elongation at break, the shrinkage rate can be suppressed with respect to the temperature of food heated in a microwave oven (about 150 ° C.), and the peel strength can withstand various moldings. , The effect of being able to mold into a desired state even with a complicated shape can be expected.

Further, by laminating the non-foaming surface layer 23 (or the non-foaming surface layer 23 on the outside of the non-foaming intermediate layer 22) on at least one surface of the heat-resistant base material 1, the heat resistance as well as the rigidity and surface smoothness are obtained. Can be improved.

The packaging container in the present embodiment may be formed by thermoforming a synthetic resin sheet by sheet molding such as vacuum forming, vacuum forming, vacuum forming, double-sided vacuum forming, and thermoforming. As deep-drawing packaging, the sheet may be molded into a container shape according to the mold.

The printing layer constituting the non-foamed laminated film in the present embodiment may be a layer containing powder, or may be, for example, a metallic luster layer having metal powder formed by printing metal ink. The metal powder is conventionally known as a metal gloss component such as aluminum powder, gold powder, silver powder, copper powder, bronze powder, zinc powder, a mixture of these powders, other metal or alloy powders, or metal vapor deposition pieces. It may be a metal powder having various forms. Further, for example, a metal powder whose color tone has been adjusted by being mixed with a colorant such as yellow or red may be used. Further, a metal film may be formed on the surface of the inorganic particles. Further, inorganic powder (for example, glass flakes, mica, sericite, talc or a mixture of two or more thereof) may be used. Further, the powder content is preferably 5 mg / m ² or more in order to sufficiently develop gloss, but if the printed layer becomes too thick, the moldability is deteriorated, so 5 to 500 mg / m ² is suitable. It is preferable, more preferably 10 to 200 mg / m ² , and even more preferably 20 to 100 mg / m ² .

The dry laminating method adopted in this embodiment is generally a method in which a predetermined adhesive is applied to the surface of a predetermined film, dried, and then pressure-bonded to another film. May be shown.

1 Heat-resistant base material 11 Foam layer 12 Surface layer 13 Intermediate layer 2 Non-foam laminate film 21 Thermoplastic resin layer 22 Printing layer P Packaging container

Claims (7)

A packaging container in which a heat-resistant base material is laminated on the outermost layer and a non-foamed laminated film is laminated on the innermost layer.
The heat-resistant substrate has a foam layer and has a foam layer.
The non-foamed laminated film has at least one thermoplastic resin layer and
The thermoplastic resin layer is biaxially stretched, has a glossiness of 100% or more, a tensile elongation at break of 100% or more, a heat shrinkage rate at 150 ° C. of 3.0% or less, and an SP value of 9.0 or more. , Thickness is 10-30 μm ,
The peel strength of the non-foamed laminated film with respect to the heat-resistant substrate is 3.0 N / 15 mm or more.
A packaging container characterized by that. The packaging container according to claim 1, wherein the thermoplastic resin layer is made of a polyester resin. The packaging container according to claim 1 or 2, wherein the thermoplastic resin layer is formed of a polybutylene terephthalate-based resin. The packaging container according to any one of claims 1 to 3 , wherein the heat-resistant base material has a non-foamed surface layer laminated on at least one surface of the foamed layer. Claims 1 to 1, wherein the heat-resistant base material has a non-foamed intermediate layer laminated on at least one surface of the foamed layer and a non-foamed surface layer laminated on the outside of the non-foamed intermediate layer. The packaging container according to any one of 4 . The packaging container according to any one of claims 1 to 5, wherein the drawing ratio of the container is 0.05 to 0.6. A method for using a packaging container according to any one of claims 1 to 6 , wherein the oily food is placed in the packaging container and heated in a microwave oven.

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