JP7110422B2 - Molded article containing gas barrier layer, packaging container containing the same, and method for producing molded article - Google Patents

Description

TECHNICAL FIELD The present invention relates to a molded article containing a gas barrier layer, a packaging container including the same, and a method for producing the molded article.

Products used as ordinary food packaging containers are divided into foaming and non-foaming types. Foam-type food packaging containers are made by extruding polystyrene mixed with foaming gas, which can keep its thickness relatively thick, so it maintains its shape, is heat-insulating, and is price-competitive. has a high advantage. On the other hand, such foaming products have the disadvantage that harmful substances are detected at high temperatures.

In the case of non-foaming food packaging containers, heat-stable polypropylene films are used. On the other hand, such a non-foaming type food packaging container has an advantage that the change rate of shape is small at high temperature and harmful substances are not detected. However, it has the disadvantages of high cost and poor insulation.

On the other hand, in modern society, as life becomes more convenient, the use of disposable items is increasing, and demand for food delivery and simple cooking products is gradually increasing due to the increase in single-person households. Along with this, the demand for food packaging containers is also increasing, and consumer needs for new container materials that are safe from harmful substances and given functions depending on the application are becoming more and more important.

In this regard, food packaging manufacturers are making great efforts to manufacture food packaging containers that are convenient, safe, environmentally friendly, and competitively priced.

As an example, technology has been proposed for environmentally friendly heat-resistant materials and packaging containers containing the same (Korea Registered Patent No. 10-1778629). Specifically, the registered patent discloses a packaging container having a two-layer heat-resistant material including an ethylene vinyl alcohol (EVOH) gas barrier layer on at least one surface of a polyethylene terephthalate (PET) foam. disclosed.

However, although ethylene vinyl alcohol has excellent barrier properties, it is difficult to mold due to a large difference in melting point from that of polyethylene terephthalate. Specifically, high-temperature heat treatment is required to improve the heat resistance of polyethylene terephthalate, but in such a case, the ethylene vinyl alcohol melts and the gas barrier layer cannot be formed over the entire area of the food packaging container. For example, there is a problem that the configuration state of the food packaging container is defective.

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a molded article that can prevent the gas barrier layer from being damaged during molding of the container, a packaging container including the molded article, and a method for manufacturing the same.

The present invention has a structure in which a first foam sheet, a gas barrier layer and a second foam sheet are laminated in order, and is a molded article satisfying the following mathematical formula 1, wherein the first foam sheet and the second foam sheet is a polyester resin foam, the average thickness of the molded product is in the range of 1 to 5 mm, and the oxygen permeability according to ASTM D 3985 is 20 cc/m ² ·day or less at 23 ° C. Provide compacts characterized by:

[Mathematical formula 1]
H/D≧0.01

In Mathematical Formula 1, forming a molded body of a container structure including a container and an opening, H represents the depth of the container and ranges from 1 to 10 cm, and D represents the diameter of the opening. .

The present invention also provides a packaging container containing the molded article.

Furthermore, the present invention provides a step of placing a sheet having a structure in which a first foam sheet, a gas barrier layer and a second foam sheet are sequentially laminated between a female mold and a male mold of a molding device; The first foam sheet and the second foam sheet are polyester resin foams.

The molding according to the present invention can minimize oxygen and moisture permeability by including first and second foam sheets on both sides of the gas barrier layer, respectively. In addition, when the molded product is used as a food packaging container, the food can be easily preserved because the food is prevented from spoiling due to oxygen and moisture.

Sectional drawing of the molded object which concerns on this invention. 3A to 3D are drawings sequentially illustrating the method for manufacturing a molded body according to the present invention;

TECHNICAL FIELD The present invention relates to a molded article containing a gas barrier layer, a packaging container including the same, and a method for producing the molded article. In particular, the molding according to the present invention can minimize oxygen and moisture permeability by including first and second foam sheets on both sides of the gas barrier layer. In addition, when the molded product is used as a food packaging container, the food can be easily preserved because the food is prevented from spoiling due to oxygen and moisture.

FIG. 1 is a cross-sectional view of a molded body according to the present invention, and FIG. 2 is a drawing sequentially illustrating a method for manufacturing a molded body according to the present invention. Hereinafter, the molded article according to the present invention will be described in detail with reference to FIGS. 1 and 2. FIG.

The present invention has a structure in which a first foam sheet 101, a gas barrier layer 102, and a second foam sheet 101' are sequentially laminated, and is a molded body 10 satisfying the following mathematical formula 1, wherein the first foam sheet 101 and the second foam sheet 101′ are polyester resin foams, the average thickness of the molded body 10 is in the range of 1 mm to 5 mm, and the oxygen permeability according to ASTM D 3985 is 20 cc/ Provide a compact characterized by m ² · day or less:

[Mathematical formula 1]
H/D≧0.01

In Mathematical Formula 1, forming a molded body of a container structure including a container and an opening, H represents the depth of the container and ranges from 1 cm to 10 cm, and D represents the diameter of the opening. .

Specifically, the molded article according to the present invention may have an oxygen permeability measured according to ASTM D3985 of 0.1 to 20 cc/m ² ·day. More specifically, when measuring the oxygen permeability of a test piece (width x length x height 40 mm x 40 mm x 3 mm) of the manufactured compact at (23 ± 1) ° C for 30 minutes, the compact ^{The oxygen permeability of} the .1-7 cc/m ² ·day, 0.1-5 cc/m ² ·day, or 0.1-3 cc/m ² ·day.

As described above, the first and second foam sheets 101 and 101' made of polyester resin are formed on the cross-sectional outer layers of the molded body 10, respectively, and a gas barrier is formed between the first and second foam sheets 101 and 101'. By forming layer 102, oxygen permeability as described above can be met. That is, the molded article 10 according to the present invention has an excellent oxygen shielding performance due to the oxygen permeability within the above range, and thus has the advantage of being able to extend the shelf life of food.

Specifically, in the molded article 10 according to the present invention, the first and second foam sheets 101 and 101' are formed on both sides of the gas barrier layer 102, respectively, and the oxygen permeability can be controlled within the above range. .

In addition, it is characterized by having a water vapor permeability of 50 g/m ² ·day or less under conditions of 37° C. and 100% relative humidity according to ASTM F 1249. For example, the water vapor permeability is 0.1 to 50 g/m ² ·day, 0.1 to 40 g/m ² ·day, 0.1 to 30 g/m ² ·day, 0.1 to 20 g/m ² ·day. , 0.1 to 10 g/m ² ·day, 0.1 to 7 g/m ² ·day, 0.1 to 5 g/m ² ·day or 0.1 to 3 g/m ² ·day. Since the molded article 10 according to the present invention has the water vapor permeability, it can be widely used for products requiring gas barrier properties. For example, when used as a food packaging container, food can be easily stored because it can prevent food from reacting with water vapor and spoiling.

The polyester resin can contain repeating units derived from acid and diol components. Specifically, the polyester resin may be one or more selected from the group consisting of aromatic and aliphatic polyester resins synthesized from dicarboxylic acid components and glycol components or hydroxycarboxylic acids.

Examples of the polyester resin include polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polylactic acid (PLA), polyglycolic acid (PGA), and polyethylene adipate. , PEA), Polyhydroxyalkanoate (PHA), Polytrimethylene terephthalate (PTT) and Polyethylene naphthalate (PEN). As an example, Polyethylene Terephthalate (PET) may be used in the present invention.

In addition, the gas barrier layer 102 may include at least one of ethylene vinyl alcohol (EVOH), polyvinylidene chloride (PVdC) and polyethylene terephthalate (PET).

Specifically, the barrier layer 102 may be formed using ethylene vinyl alcohol. In this case, the gas generated by the food inside the packaging container can be discharged to the outside, and the supply of oxygen from the outside can be cut off.

The molded body 10 according to the present invention is a multilayer structure, and the average thickness of the multilayer structure forming the molded body 10 can be in the range of 1 mm to 5 mm.

For example, the molded body 10 can be a three-layer structure, in which case the overall thickness of the three-layer structure can be an average of 1.2-4 mm, 1.5-3.5 mm, 1.8-3 mm or 2 mm. . Also, the average thickness of the gas barrier layer 102 may be 0.01-2 mm, 0.05-2 mm, 0.1-1.9 mm, 0.2-1.85 mm, 0.3-1.8 mm. , 0.5-1.6 mm, 0.7-1.4 mm, 0.9-1.2 mm, or 1 mm.

Together, the average thickness of the first foam sheet 101 and the second foam sheet 101′ can be 0.5-1.5 mm, respectively, 0.6-1.3 mm, 0.7-1.2 mm, 0.6-1.3 mm, 0.7-1.2 mm. It can be 8-1.0 mm, 0.9-0.95 mm. By comprising the foamed sheets 101 and 101' and the gas barrier layer 102 having thicknesses within the above range, the molded article 10 of the present invention can satisfy the oxygen permeability and the water vapor permeability described above, and also has a compressive strength. can be improved, and lightness and the like can be satisfied at the same time.

In one example, the melting point _Tm of the first and second foam sheets 101, 101' can be 240-260°C on average. Specifically, the average melting point of the first and second foam sheets 101, 101' can be 242°C to 257°C, 245°C to 255°C, 247°C to 253°C, or 248°C to 251°C. As an example, the melting point of the first and second foam sheets 101, 101' comprising polyethylene terephthalate resin may average between 248°C and 251°C.

In addition, the melting point _Tm of the gas barrier layer 102 may range from 150°C to 190°C on average. Specifically, the melting point of the gas barrier layer 102 can average 150°C to 190°C, 155°C to 185°C, 160°C to 180°C, 165°C to 175°C, or 169°C to 171°C. As an example, the melting point of the gas barrier layer made of ethylene vinyl alcohol can be 170±0.5° C. on average.

On the other hand, since polyethylene terephthalate and ethylene vinyl alcohol have a large melting point difference, ethylene vinyl alcohol is peeled off or melted during molding of a two-layer structure (foamed sheet/gas barrier layer) molding, and the barrier layer covers the entire area of the molding. However, by laminating the foamed sheets 101 and 101′ on both sides of the gas barrier layer 102, the gas barrier layer 102 is melted away and the foamed sheet 101, Problems such as separation from 101' can be solved.

As an example, the molded body 10 according to the present invention includes a bottom portion 11 and a wall portion 12 with an open upper end along the circumference of the bottom portion 11, and the H/D value in Equation 1 is 0.01. ~1.3, 0.05-1.2, 0.1-1.1, 0.3-1.0, 0.4-0.9, 0.5-0.8, 0.55-0 .7 or 0.6 to 0.65. In addition, the H value in Equation 1 may range from 1 to 10 cm. As an example, the diameter of the opening of the molded body 10 may be 10 cm, and the depth of the receiving portion may be 3 cm. Together, the molded body 10 according to the present invention may be in the shape of a container, and may be in the shape of a cylindrical or square container.

On the other hand, the molded body 10 according to the present invention provides the molded body 10 that satisfies Equation 2 below by forming the first and second foam sheets 101 and 101' on both sides of the gas barrier layer 102, respectively. be able to:

[Mathematical formula 2]
|T ₂ −T ₁ |≧10° C.

In the above formula ₂ , T1 is the outer surface temperature of the molded body measured after one minute has elapsed after the molded body is filled with water of 100°C under the conditions of 20°C and ₁ atm, and T2 is 20°C. It is the temperature of the water inside the molded body measured when water of 100° C. is poured into the molded body under 1 atm condition and one minute has passed.

The molding 10 according to the present invention exhibits excellent heat insulation properties by including the first and second foam sheets 101, 101'. Specifically, at room temperature (20 ° C.) and 1 atmospheric pressure, 70% (v / v) of water at 100 ° C. was added to the inside of the compact, and after 1 minute, the water inside the compact The temperature difference between the temperature of and the surface of the outside of the molded body can be 10° C. or more. This indicates that the molded article 10 according to the present invention has excellent heat shielding properties. This is the temperature difference between the temperature of the water contained inside the molded body 10 and the temperature of the outer surface of the molded body 10 after one minute has passed.

As an example, when 70% (v/v) of water at 100°C is added to the molded body 10 according to the present invention, and the external temperature of the molded body is 40°C after one minute has passed, molding The temperature of the water contained inside body 10 may be 95°C. The molded article 10 according to the present invention exhibits excellent heat shielding properties by maintaining a relatively high temperature difference between the temperature of the water contained inside the molded article 10 and the outer surface of the molded article 10 under the above conditions. It can be seen that this can effectively improve the heat retention of the food.

Meanwhile, the first and second foam sheets 101, 101' of the present invention may each contain 0.5-9% by weight of calcium carbonate (CaCO ₃ ).

Specifically, the calcium carbonate (CaCO ₃ ) is inorganic particles, and by including the inorganic particles, the surfaces of the first and second foam sheets 101 and 101′ of the present invention are uniform. It has excellent thermoformability.

The thermal conductivity of the calcium carbonate may range from 1.0 kcal/mh°C to 3.0 kcal/mh°C. Specifically, the thermal conductivity of calcium carbonate is 1.2 kcal/mh°C to 2.5 kcal/mh°C, 1.5 kcal/mh°C to 2.2 kcal/mh°C, or 1.8 kcal/mh°C to 2.0 kcal. /mh°C. More specifically, the thermal conductivity of calcium carbonate can be from 1.5 kcal/mh°C to 2.5 kcal/mh°C or from 1.8 kcal/mh°C to 2.3 kcal/mh°C. As described above, the first and second foamed sheets 101 and 101' containing calcium carbonate exhibit excellent thermal conductivity, have a uniform surface, and exhibit excellent thermoformability.

For example, the calcium carbonate content may be 0.5-9% by weight. Specifically, the content of calcium carbonate is 0.5-8 wt%, 0.6-7 wt%, 0.7-6 wt%, 0.8-5 wt%, 0.9-4 wt%, It can be 1.0-3.0% by weight, 2%-3.5% by weight. As an example, it can be 1.0 wt% or 3 wt%.

In one example, the density (KS M ISO 845) of the foam sheets 101, 101' can average ^300-700 kg/m3. Specifically, the density of the foam sheets 101, 101′ is 325-650 kg/m ³ , 350-600 kg/m ³ , 375-550 kg/m ³ , 400-500 kg/m ³ or 425-450 kg/m ³ on average. can be

In another example, the foam sheets 101, 101' according to the present invention may have a high temperature elongation of 325-375% at 200° C. for 10 seconds. Specifically, the foam sheets 101 and 101' may have a high temperature elongation of 330-360%, 345-370%, or 335-360% at 200° C. for 10 seconds. More specifically, the foam sheets 101 and 101' may have a high temperature elongation of 345 to 355% at 200° C. for 10 seconds.

By including polyester and calcium carbonate as described above, the foam sheets 101 and 101' according to the present invention can exhibit excellent workability.

The first and second foam sheets 101 and 101' of the molded article 10 according to the present invention are polyester resin foams, and the polyester resin of the first and second foam sheets 101 and 101' is polyethylene terephthalate. , PET) resin. By using the PET resin, it is environmentally friendly and easy to reuse.

Based on the standards of the Ministry of Food and Drug Safety for equipment, containers and packaging and their raw materials, the total amount of discharge is less than 30ppm when measuring discharge standards, and antimony, germanium, terephthalic acid, isophthalic acid, and acetaldehyde substances are not detected. It is characterized by the fact that no volatile substances are detected when the residual specification is measured.

Specifically, the molding 10 according to the present invention uses polyester resin, which is an environment-friendly material, as described above, so that the full text of the standards and standard notices for utensils and containers and packaging issued by the Ministry of Food and Drug Safety of the Republic of Korea is satisfied. Substances of concern listed in Notification No. 2015-7 can be adjusted within acceptable limits.

By manufacturing the food packaging container 10 using the molding 10 using such materials, it is possible to provide an environment-friendly food container.

As an example, the molded body 10 according to the present invention may have a barrier function, a hydrophilic function, or a waterproof function. one or more functional additives selected from the group consisting of extenders, infrared attenuators, plasticizers, fire retardant chemicals, pigments, elastomeric polymers, extrusion aids, antioxidants, anti-slip agents and UV absorbers. can further include: Specifically, the resin foam sheet of the present invention can contain thickeners, heat stabilizers and foaming agents.

Although the thickener is not particularly limited, pyromellitic dianhydride (PMDA) may be used in the present invention.

The thermal stabilizer can be an organic or inorganic phosphorus compound. Said organic or inorganic phosphorus compounds can be, for example, phosphoric acid and its organic esters, phosphorous acid and its organic esters. For example, the thermal stabilizer is a commercially available substance and can be phosphoric acid, alkyl phosphate or aryl phosphate. Specifically, the thermal stabilizer in the present invention may be triphenyl phosphate, but it is not limited to this. It can be used without restrictions within the range of

Examples of the blowing agent include physical blowing agents such as N ₂ , CO ₂ , freon, butane, pentane, neopentane, hexane, isohexane, heptane, isoheptane, methyl chloride, or azodicarbonamide-based compounds, P, P'-oxybis (benzenesulfonyl hydrazide) [P, P'-oxy bis (benzene sulfonyl hydrazide)] type compounds, N, N'-dinitrosopentamethylene tetramine (N, N'-dinitroso pentamethylene tetramine) type compounds, etc. There are chemical blowing agents, specifically _CO2 can be used in the present invention.

The present invention also provides a method for producing a molded article.

2A to 2C are drawings sequentially illustrating the method for manufacturing a molded body according to the present invention. Referring to FIG. 2, the present invention provides a sheet 1 having a structure in which a first foam sheet, a gas barrier layer and a second foam sheet are laminated in order, between a female mold 21 and a male mold 22 of a molding device. and pressing the male mold 22 to form the molded article 10, wherein the first foam sheet and the second foam sheet are polyester resin foams. A manufacturing method is provided.

On the other hand, the manufacturing method for the first and second foam sheets is not specifically limited, but for example, the first and second foam sheets can be manufactured by extruding and foaming a polyester resin. Specifically, foaming methods are broadly classified into bead foaming and extrusion foaming. Generally, the beads are foamed by heating the resin beads for primary foaming, aging them for an appropriate time, filling them in a plate-like or cylindrical mold, heating them further, and performing secondary foaming. It is a method of making products by fusing and molding. On the other hand, in extrusion foaming, the resin is heated and melted, and the resin melt is continuously extruded and foamed, which simplifies the process steps and enables mass production. Cracks and granulation phenomena between beads can be prevented.

Next, in the step of processing, the sheet 1 having a structure in which the first foam sheet, the gas barrier layer and the second foam sheet are laminated in this order is placed between the female mold 21 and the male mold 22 of the molded body molding device 20. and pressing the male mold 22 to form the compact 10 .

Specifically, the sheet 1 placed between the female mold 21 and the male mold 22 can be formed into the compact 10 by being thermoformed. The thermoforming includes vacuum forming, pressure forming, or vacuum pressure forming combining vacuum forming and pressure forming, using a male mold (plug), or after using a male mold 22, vacuum and/or There is thermoforming such as pressure forming.

Referring to FIG. 2, FIG. 2(a) shows the placing step of placing the sheet 1 between the female mold 21 and the male mold 22 of the forming apparatus before molding the sheet 1. As shown in FIG. FIG. 2(b) is a drawing showing the stretching process and the heating process. As shown in FIG. It is formed into the shape of the cavity of the female mold 21 by vacuum suction and heat is applied. FIG. 2(c) shows that the molded sheet 1 is shaped into the shape of the male mold 22 by the pressurization of the male mold 22 and the compressed air from the female mold 21, resulting in the final molded product. A certain molding 10 is shown to be molded. The molded compact 10 can then be removed by raising the male mold 22 after cooling.

In addition, in the molding step, heat is applied so that the surface temperature of the sheet is 140 to 160°C, and the surface temperatures of the female mold 21 and the male mold 22 are set to 60°C to 200°C. The molded body 10 can be molded by pressing.

Meanwhile, the surface temperatures of the male mold 22 and the cavity of the female mold 21 may differ from each other during the molding process. Preferably, the surface temperature of the male mold 22 can be 250-280°C, 255-275°C, 260-270°C or 265°C, respectively, and the surface temperature of the cavity of the female mold 21 is 200-250°C, It can be 210-240°C, 215-235°C, 220-230°C or 225±3°C.

In one example, the surface temperature of the male mold 22 can be 265±1° C., the surface temperature of the female mold 21 can be 225° C., and the male mold 22 can be heated for 0.5 to 15 seconds. It is preferable to contact the female mold 21 during In addition, the female mold 21 may have a structure in which a decompression hole 23 for decompressing a cavity, which is an internal space, is formed on one side.

As a result, a container-shaped molded body in which the first polyester resin foam sheet, the gas barrier layer, and the second polyester resin foam sheet are laminated in order by the above-described molded body manufacturing method, or a packaging container including the molded body can be manufactured.

Hereinafter, the present invention will be described in more detail with reference to Examples and Experimental Examples.

However, the following examples and experimental examples are only for illustrating the present invention, and the content of the present invention is not limited to the following examples and experimental examples.

Production example 1.
100 parts by weight of PET resin was dried at 130° C. to remove moisture, and 100 parts by weight of PET resin from which moisture was removed by a first extruder, 1 part by weight of PMDA (pyromellitic dianhydride), and calcium carbonate (CaCO ₃ ). 1 part by weight and 0.1 part by weight of Irganox (IRG 1010) were mixed and heated to 280° C. to prepare a resin melt. After that, butane gas was mixed as a foaming agent in the first extruder, and the resin melt was sent to the second extruder and cooled to 220°C. The cooled resin melt was passed through a die to form a foam sheet.

At this time, the manufactured polyester resin foam sheet had a density of 380 kg/m ³ and a thickness of 1 mm.

Example 1
A 0.05 mm EVOH film was laminated as a barrier layer on one surface of the foamed sheet produced in Production Example 1, and the foamed sheet produced in Production Example 1 was laminated thereon. Then, the laminated three-layer structure sheet was molded into a container shape to produce a molded body with H/D=0.3 (H: depth of container portion D: diameter of opening portion). The diameter of the opening of the molding was 10 cm. On the other hand, the surface temperature of the male mold was 60°C and the surface temperature of the female mold was 120°C during molding of the compact.

Example 2.
A molded body was manufactured in the same manner as in Example 1, except that the barrier layer consisted of 2 layers of 0.02 mm EVOH and 0.03 mm PET film.

Example 3.
A compact was produced in the same manner as in Example 1, except that the H/D value was 0.5.

Comparative example 1
A 0.05 mm thick EVOH film was laminated as a barrier layer on one surface of the foamed sheet manufactured in the same manner as in Preparation Example 1 except that the thickness was 2 mm, thereby manufacturing a two-layer sheet. Then, the laminated two-layered sheet was molded into a container shape to produce a molded body with H/D=0.3 (H: depth of container portion D: diameter of opening portion). The diameter of the opening of the molding was 10 cm. On the other hand, the surface temperature of the male mold was 60°C and the surface temperature of the female mold was 120°C.

Comparative example 2
A PP multilayer sheet (PP/EVOH/PP) was used to mold a container having the same structure as Example 1 with H/D of 0.3, and the temperature of the mold was maintained at 20°C during molding.

In Examples and Comparative Examples, molded bodies were produced by changing the type of sheet and molding conditions as shown in Table 1 below.

Experimental example 1. Measurement of Oxygen Permeability The molded articles produced in Examples and Comparative Examples were measured for oxygen permeability under conditions of a temperature of 23° C. and a relative humidity of 50%. On the other hand, in order to confirm whether the gas barrier layer was evenly distributed in the molded article, a test piece of the molded article was randomly cut and measured. The results are shown in Table 2 below.

<Oxygen permeability test>
- Test method: ASTM D 3985
- Test equipment: OX-TRAN 702 (MOCON, USA)
- Test temperature: 23°C
-Test time: 30 minutes -Measurement range: 0.1 to 2000 cc/m ² day
- Specimen size: width x length x height 40mm x 40mm x 3mm

Referring to Table 2, it can be seen that the molded article according to the present invention has a low oxygen permeability, and accordingly, it can be seen that oxygen permeation can be substantially prevented. This means that the gas barrier layer is uniformly distributed over the entire area of the compact. On the other hand, it was confirmed that the molded article of Comparative Example 1 had a high oxygen permeability. It is considered that this is because the gas barrier layer was damaged during molding of the molded article. In addition, in the case of Comparative Example 2, which is a non-foamed product, although the oxygen permeability is low, it can be confirmed that the heat barrier property is not excellent in the heat barrier property test described below.

On the other hand, it was confirmed that the molded article of Comparative Example 1 had a high oxygen permeability. It is considered that this is because the gas barrier layer was damaged during molding of the molded article. In addition, although Comparative Example 2, which is a non-foamed product, has low oxygen permeability, it can be confirmed that the heat barrier property is not excellent in the heat barrier property test described below.

Experimental example 2. Measurement of Water Vapor Permeability The molded bodies produced in Examples and Comparative Examples were measured for water vapor permeability under conditions of a temperature of 37° C. and a relative humidity of 100% based on ASTM F 1249. The results are shown in Table 3 below.

Referring to Table 3, the compacts according to Examples 1-3 showed low results of 8.5 g/m ² day, 17 g/m ² day and 18 g/m ² day, respectively. This means that the gas barrier layer is uniformly distributed over the entire area of the compact. In addition, in the case of Comparative Example 1, it was 19 g/m ² day, which was higher than that of the Examples. It is considered that this is because the gas barrier layer was damaged during molding of the molded article of Comparative Example 1. In addition, although Comparative Example 2, which is a non-foamed product, has low oxygen permeability, it can be confirmed that the heat barrier property is not excellent in the heat barrier property test described below.

Experimental example 3. Measurement of Thermal Insulation Properties In order to evaluate the thermal insulation properties of the molded articles of Examples and Comparative Examples, 70% (v/v) water at 100° C. was added to the interior of the molded articles, and after 2 minutes, , the temperature was measured at an arbitrary point inside the compact and at an arbitrary point outside the container. And the results are shown in Tables 4 and 5:

[Mathematical formula 2]
|T ₂ −T ₁ |≧10° C.

In the above formula ₂ , T1 is the outer surface temperature of the molded body measured after one minute has elapsed after the molded body is filled with water of 100°C under the conditions of 20°C and ₁ atm, and T2 is 20°C. It is the temperature of the water inside the molded body measured when water of 100° C. is poured into the molded body under 1 atm condition and one minute has passed.

Referring to Table 4, the molded articles according to the examples showed a temperature difference of 10° C. or more between the temperature of the water contained inside the molded article and the temperature of the surface of the molded article, indicating excellent heat shielding properties. I understand. On the other hand, the molded articles according to Comparative Examples 1 and 2 had |T ₂ -T ₁ | Therefore, it has been confirmed that the molded article according to the present invention has excellent heat insulation properties by including the PET foam sheet, thereby realizing excellent heat retention properties and safe handling.

In particular, it can be confirmed that the gas barrier layer has excellent heat shielding properties by including the first and second foam sheets on both sides thereof.

Through this, it can be seen that the molded article according to the present invention has low water vapor permeability and low oxygen permeability, and excellent heat shielding properties.

The molded article according to the present invention can minimize oxygen and moisture permeability by including the first and second foam sheets on both sides of the gas barrier layer, respectively. In addition, it is possible to prevent food from spoiling due to moisture, and it is easy to store food.

1: Sheet 10: Molded body 101: First foam sheet 101': Second foam sheet 102: Gas barrier layer 11: Bottom part 12: Wall part 13: Flange 20: Mold 21: Female mold 22: Male mold Type 23: decompression hole

Claims (14)

A structure in which a first foam sheet, a gas barrier layer and a second foam sheet are laminated in order,
The first foam sheet and the second foam sheet are polyester resin foams,
A molded article, wherein the average thickness of the first foam sheet and the second foam sheet is 0.5 to 1.5 mm. The compact according to claim 1, characterized in that it satisfies the following mathematical formula 1:
[Mathematical formula 1]
H/D≧0.01
In formula 1,
Although forming a molded body of a container structure including a container and an opening,
H indicates the depth of the housing portion and is 1 cm to 10 cm,
D indicates the diameter of the opening. Water vapor transmission rate according to ASTM F 1249 is 50 g/m ² ·day or less under conditions of 37 ° C. and 100% relative humidity,
3. The molded article according to claim 1, wherein the oxygen permeability according to ASTM D 3985 is 20 cc/m< ² > .day or less at 23[deg.]C. The molded article according to any one of claims 1 to 3, wherein the gas barrier layer has an average thickness of 0.01 to 2 mm, and the molded article has an average thickness of 1 mm to 5 mm. The molded article according to any one of claims 1 to 4, wherein the gas barrier layer contains one or more of ethylene vinyl alcohol, polyvinylidene chloride and polyethylene terephthalate. The melting point (T _m ) of the gas barrier layer is 150° C. to 190° C. on average,
The molded article according to any one of claims 1 to 5, wherein the melting point (T _m ) of the first and second foam sheets is 240°C to 260°C on average. The molded article according to any one of claims 1 to 6, wherein the polyester resin is a polyethylene terephthalate resin. The molding according to any one of claims 1 to 7, characterized in that the first and second foam sheets each contain 0.5 to 9.0% by weight of calcium carbonate. The molded article according to any one of claims 1 to 8, characterized in that it satisfies the following mathematical formula 2:
[Mathematical formula 2]
|T ₂ −T ₁ |≧10° C.
In the mathematical formula 2,
T ₁ is the outer surface temperature of the molded body measured after 1 minute has passed after the molded body is filled with water of 100 ° C. under the conditions of 20 ° C. and 1 atm,
T2 is the temperature of the water inside the compact measured after one minute has passed after the compact was filled with water of 100°C under the conditions of ₂₀ °C and 1 atm. A packaging container comprising the molded article according to any one of claims 1 to 9. 11. The packaging container according to claim 10, wherein the packaging container is a food packaging container. disposing a sheet having a structure in which a first foam sheet, a gas barrier layer and a second foam sheet are laminated in order between a female mold and a male mold of a molding device; and pressurizing the male mold. forming the compact with;
The first foam sheet and the second foam sheet are polyester resin foams,
A method for producing a molded article, wherein the first foam sheet and the second foam sheet each have an average thickness of 0.5 to 1.5 mm. In the molding step, heat is applied so that the surface temperature of the sheet is 140 to 160° C., and the surface temperature of the female mold and the male mold is set to 60 to 200° C. to mold the molded body. 13. The method for producing a molded article according to claim 12, characterized by: 14. The method of claim 12 or 13, wherein the female mold has a structure in which a decompression hole for decompressing the internal space is formed on one side.

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