CN110612209A - Composite sheet for food container having excellent heat resistance and processability, and method for producing same - Google Patents
Composite sheet for food container having excellent heat resistance and processability, and method for producing same Download PDFInfo
- Publication number
- CN110612209A CN110612209A CN201880029022.7A CN201880029022A CN110612209A CN 110612209 A CN110612209 A CN 110612209A CN 201880029022 A CN201880029022 A CN 201880029022A CN 110612209 A CN110612209 A CN 110612209A
- Authority
- CN
- China
- Prior art keywords
- food
- composite sheet
- foamed sheet
- resin layer
- sheet
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C44/00—Shaping by internal pressure generated in the material, e.g. swelling or foaming ; Producing porous or cellular expanded plastics articles
- B29C44/34—Auxiliary operations
- B29C44/56—After-treatment of articles, e.g. for altering the shape
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B27/00—Layered products comprising a layer of synthetic resin
- B32B27/06—Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B27/00—Layered products comprising a layer of synthetic resin
- B32B27/18—Layered products comprising a layer of synthetic resin characterised by the use of special additives
- B32B27/20—Layered products comprising a layer of synthetic resin characterised by the use of special additives using fillers, pigments, thixotroping agents
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B27/00—Layered products comprising a layer of synthetic resin
- B32B27/36—Layered products comprising a layer of synthetic resin comprising polyesters
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
- B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
- B65D81/00—Containers, packaging elements, or packages, for contents presenting particular transport or storage problems, or adapted to be used for non-packaging purposes after removal of contents
- B65D81/18—Containers, packaging elements, or packages, for contents presenting particular transport or storage problems, or adapted to be used for non-packaging purposes after removal of contents providing specific environment for contents, e.g. temperature above or below ambient
- B65D81/20—Containers, packaging elements, or packages, for contents presenting particular transport or storage problems, or adapted to be used for non-packaging purposes after removal of contents providing specific environment for contents, e.g. temperature above or below ambient under vacuum or superatmospheric pressure, or in a special atmosphere, e.g. of inert gas
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Laminated Bodies (AREA)
- Manufacture Of Porous Articles, And Recovery And Treatment Of Waste Products (AREA)
- Wrappers (AREA)
- Packages (AREA)
Abstract
The present invention relates to a composite sheet for food containers comprising a polyester resin foamed sheet and a polyester resin layer, and a method for preparing the same, and a food container formed from the composite sheet can satisfy both high heat resistance and excellent processability by controlling crystallinity.
Description
Technical Field
The present invention relates to a composite sheet for food containers excellent in heat resistance and processability, a food container formed from the composite sheet, and a method for producing the composite sheet.
Background
Products used as general food containers are classified into foamed type and non-foamed type. A foamed product is obtained by mixing and extruding polystyrene and a foaming gas, and has advantages such as shape maintenance, heat insulation, and price advantage because the product can maintain a thick thickness. In contrast, such foamed products have the disadvantage that harmful substances are detected at high temperatures. A product prepared by using polypropylene, which is stable to heat, in a film-forming form is used as a non-foamed container, which has advantages of low change rate of form at high temperature and no detection of harmful substances, but has disadvantages of high price and poor heat insulation effect (korean laid-open patent No. 10-2012-0058347).
A typical product most commonly used as a disposable heat-resistant container is a bowl-noodle container, and a polystyrene foam container has been used, but a harmful substance is detected at a high temperature, and a paper container is used instead, but the disposable heat-resistant container has a disadvantage of being expensive.
With the increasingly convenient life of modern society, the use amount of disposable articles increases, and with the increase based on one person one house type, the demand for take-out food and simple cooking products also gradually increases. Accordingly, the demand for food packaging containers has increased, and further, the consumer demand for new container materials that are safe without harmful substances and have functions based on different uses has also increased day by day.
Further, the inside of the container requires a space for storing food, and thus a high level of processability is required. Further, low temperature characteristics are required for freezing or cold storage, and high temperature characteristics are required at a high level for use in an oven or a microwave oven.
Therefore, there is a need for a new packaging container having processability, low temperature characteristics, and high temperature characteristics while not emitting hazardous substances.
Disclosure of Invention
Technical problem
The present invention relates to a composite sheet for food containers excellent in heat resistance and processability, a food container formed from the composite sheet, and a method for producing the composite sheet.
Means for solving the problems
In one embodiment, the composite sheet for food containers of the present invention,
the method comprises the following steps:
a foamed sheet of polyester resin; and
a polyester resin layer formed on one or both surfaces of the foamed sheet,
one or more layers of the foamed sheet and the resin layer contain inorganic particles contained in the layer,
the content of the inorganic particles is in the range of 0.01 to 10 parts by weight based on 100 parts by weight of one or more layers of the foamed sheet and the resin layer,
the average size of the inorganic particles is 10 μm or less.
In another embodiment, the present invention provides a food container comprising the above composite sheet and having a crystallinity of 20% or more.
In another embodiment, the method for preparing a composite sheet for a food container according to the present invention,
the method comprises the following steps:
a step of preparing a foamed sheet by extrusion foaming of a polyester resin obtained by polymerizing an acid component and a diol component;
forming a polyester resin layer on one or both surfaces of the foamed sheet; and
heating and pressing the foamed sheet having the resin layer formed thereon to form a recessed shape having an upper opening,
the acid component contains one or more of terephthalic acid and terephthalic acid derivatives, and one or more of isophthalic acid, isophthalic acid derivatives, and phthalic anhydride,
the layer containing inorganic particles contained in the layer is one or more of the foamed sheet and the resin layer.
ADVANTAGEOUS EFFECTS OF INVENTION
The composite sheet for food containers of the present invention can satisfy both high heat resistance and excellent processability by controlling the crystallinity of a foamed sheet of a polyester resin and the crystallinity of a resin layer formed on the foamed sheet.
Detailed Description
The invention provides a composite sheet for a food container.
The composite sheet comprises a foamed sheet of polyester resin; and a polyester resin layer formed on one or both surfaces of the foamed sheet, wherein one or more layers of the foamed sheet and the resin layer contain inorganic particles contained in the layer, the content of the inorganic particles is in the range of 0.01 to 10 parts by weight based on 100 parts by weight of the one or more layers of the foamed sheet and the resin layer, and the average size of the inorganic particles is 10 μm.
For example, the inorganic particles may be contained in an amount of 0.01 to 8 parts by weight, 0.01 to 5 parts by weight, 0.01 to 3 parts by weight, 0.01 to 1 part by weight, 1 to 10 parts by weight, or 5 to 10 parts by weight, based on 100 parts by weight of one or more layers of the foamed sheet and the resin layer.
Also, for example, the average size of the above inorganic particles may be 1 μm to 10 μm, 1 μm to 8 μm or less, 1 μm to 6 μm or less, 1 μm to 4 μm or less, or 1 μm to 2 μm or less.
The inorganic particles may contain talc, CaCO3、TiO2And one or more of SiO,
in the present invention, both the foamed sheet and the resin layer may include inorganic particles. The polyester resin layer may be formed as a coating layer or laminated with a resin film. According to one embodiment, the foamed sheet and the resin layer are each formed of a polyethylene terephthalate resin.
The foamed sheet of polyester resin comprises repeating units derived from an acid component and a diol component, wherein the acid component is one or more selected from the group consisting of terephthalic acid derivatives, isophthalic acid derivatives and phthalic acid derivatives,
the diol component is one or more selected from ethylene glycol, 2-methyl-1, 3-propanediol (2-methyl-1, 3-propanediol, MP), neopentyl glycol (neopentylglycol), 1,2-propanediol (1,2-propanediol), diethylene glycol (diethylene glycol) and isosorbide,
the repeating units derived from the terephthalic acid derivative and the ethylene glycol derivative account for 80 to 99 mol% with respect to the total repeating units.
Specifically, the foamed sheet of the present invention may be a foamed sheet of a polyester resin including a repeating unit derived from an acid component and a diol component. For example, the acid component may necessarily contain a terephthalic acid derivative, and may further contain one or more selected from an isophthalic acid derivative and a phthalic acid derivative as the case may be. The diol component may contain an ethylene glycol derivative, and may further contain one or more selected from 2-methyl-1, 3-propanediol (MP), neopentyl glycol (neopentylglycol), 1,2-propanediol (1,2-propanediol), diethylene glycol (diethylene glycol), and isosorbide (isosorbide) according to circumstances.
According to one embodiment, the repeating units derived from the terephthalic acid derivative and the ethylene glycol derivative may account for 80 to 99 mol% with respect to the total repeating units. Specifically, the repeating units derived from the terephthalic acid derivative and the ethylene glycol derivative may account for 80 to 99 mol%, 85 to 99 mol%, or 90 to 99 mol% relative to the total repeating units. More specifically, the repeating units derived from the terephthalic acid derivative and the ethylene glycol derivative may account for 92 to 99 mol%, or 96 to 98 mol%, relative to 100 mol% of the total repeating units. When the repeating units derived from the terephthalic acid derivative and the ethylene glycol derivative are contained in the above-mentioned content, the crystallinity of the foamed sheet can be adjusted to an appropriate range.
For example, in the above acid component, the repeating unit derived from one or more selected from isophthalic acid derivatives and phthalic acid derivatives may account for 1 to 10 mol% relative to the total repeating units. Specifically, the repeating unit derived from an isophthalic acid derivative or a phthalic acid derivative may account for 1 to 8 mol%, or 2 to 4 mol%, relative to the total repeating units.
In the diol component, the repeating units derived from one or more selected from the group consisting of 2-methyl-1, 3-propanediol (MP), neopentyl glycol (neopentylglycol), 1,2-propanediol (1,2-propanediol), diethylene glycol (diethylene glycol), and isosorbide (isoside) may account for 1 to 10 mol% of the total repeating units. Specifically, the repeating units derived from 2-methyl-1, 3-propanediol (2-methyl-1, 3-propanediol, MP), neopentyl glycol (neopentylglycol), 1,2-propanediol (1,2-propanediol), diethylene glycol (diethylene glycol), or isosorbide (isosorbide) may account for 1 to 8 mol%, or 2 to 4 mol%, relative to the total repeating units.
The polyester resin copolymer containing the acid component or the glycol component as described above has an increased degree of freedom, so that the melting point of the foamed sheet is lowered, and the crystallinity of the foamed sheet is lowered, whereby the food container is prevented from being hardened, the elongation is improved, and the strength against a stacking load or an external impact is improved. Further, since the polyester resin has excellent heat resistance and cold resistance, a food container including the polyester resin is easy to store in a frozen state.
In the present invention, the foamed sheet and the polyester resin layer of the polyester resin are formed separately in the same composition and content but different from each other in whether or not foamed.
For example, the foamed sheet and/or the polyester resin layer of the polyester resin of the present invention may have an average crystallinity of 5% to 40%. Specifically, the above average crystallinity may be 5% to 30%, 5% to 20%, 15% to 40%, or 20% to 35%. When the foamed sheet and the resin layer having the crystallinity in the above ranges are applied, the composite sheet has excellent impact strength and can prevent deformation due to a stacking load and/or an external impact. Therefore, when used as a food container, the product contained therein can be prevented from deteriorating.
Also, the foamed sheet of the present invention may have an average thickness of 0.5mm to 5 mm. Specifically, the thickness of the above foamed sheet may be 0.8mm to 4.0mm, 1.0mm to 3.5mm, more specifically, the thickness of the foamed sheet may be 1.0mm to 4.0mm or 1.3mm to 3.0 mm. The resin layer formed on one or both surfaces of the foamed sheet is controlled to be 1.8mm or less.
The composite sheet of the present invention may satisfy the following mathematical formula 1.
Mathematical formula 1: v is more than or equal to 50%1-V0|/V0×100≤300％；
In the above-mentioned mathematical formula 1,
V0represents the volume (mm) of the composite sheet before exposure to a temperature of 200 ℃ for 30 seconds3) And V1 represents the volume (mm) of the composite sheet after exposure to a temperature of 200 ℃ for 30 seconds3)。
Specifically, the dimensional change rate before and after exposure to a temperature of 200 ℃ for 30 seconds was measured for a sample of a food container. This is an evaluation considering the case where the above-described food container is used in an oven. For example, the volume may be the product of the length, width and thickness of the foamed sheet. For example, the dimensional change rate according to the above mathematical formula 1 may range from 50% to 300%, 50% to 250%, 50% to 200%, 50% to 150%, 50% to 100%, 50% to 80%, 80% to 300%, 100% to 300%, 150% to 300%, 200% to 300%, 250% to 300%, 80% to 250%, or 100% to 200%. The value satisfying the above-described numerical expression 1 indicates that the foamed sheet of the present invention hardly undergoes a morphological change even when used in a high-temperature environment. As a result, the foamed sheet of the present invention was found to have excellent heat resistance.
As an example of this, the following is given,the food container of the present invention has an impact strength of 5KJ/m at-10 ℃ according to ASTM D2562Or more. Specifically, the impact strength of the food container may be 5KJ/m2To 50KJ/m2、8KJ/m2To 45KJ/m2Or 10KJ/m2To 40KJ/m2. The food container of the present invention has an impact strength in the above range, and the food container can protect a product from external impact, and stably store food particularly at low temperatures.
The foamed sheet may have an average cell size of 10 to 690 μm, and the composite sheet may satisfy the following equation 2.
Mathematical formula 2: i Vb-Va|/Va×100≤10％；
In the above-mentioned mathematical formula 2,
Vathe volume (cm) of the food container before the 500g ball was allowed to freely fall from the height of 30cm to the composite sheet3)，VbThe volume (cm) of the food container after a 500g ball was allowed to freely fall from a height of 30cm to the composite sheet3)。
Specifically, the rate of change in volume from a height of 30cm to the front and rear of the prepared composite sheet test piece with a 500g ball was measured. This is a measure corresponding to the environment in which the food container is subjected to impact as described above. For example, the volume may be a product of lengths of the length, width and thickness of the food container, and the volume change rate according to the above equation 2 may range from 0.01% to 10%, from 0.05% to 8%, from 0.1% to 5%, or from 1% to 3%. Satisfying the value of equation 2 in the above range, the food container thus prepared hardly undergoes morphological changes even when subjected to strong impact
The foamed sheet described above may have an average cell size of 10 to 690 μm, 10 to 650 μm, 10 to 600 μm, 10 to 550 μm, 10 to 500 μm, 10 to 450 μm, 10 to 400 μm, 10 to 350 μm, 10 to 300 μm, 10 to 250 μm, 10 to 200 μm, 10 to 150 μm, 10 to 100 μm, 10 to 50 μm, 50 to 690 μm, 100 to 690 μm, 200 to 690 μm, 400 to 690 μm, 500 to 690 μm, 100 to 600 μm, 200 to 500 μm, or 300 to 400 μm.
According to one embodiment, the foamed sheet and/or the resin layer suitable for the composite sheet of the present invention may be added with inorganic particles at the resin polymerization step.
For example, when preparing a foam, a master batch (master batch) is simultaneously charged with a resin solution and a nucleating agent to cause foaming. However, the nucleating agent to be charged is poor in dispersibility in the resin solution. Due to the low dispersibility of the nucleating agent, the size of cells is not uniform in the foaming process, and the content is not uniform due to process errors according to the situation. In order to improve the above phenomenon, in the present invention, inorganic particles (inorganic substance) may be added in advance in a polymerization step as a polyester resin production step to improve the dispersibility of the inorganic particles.
The foamed sheet may further include inorganic particles contained in the foamed sheet, and the content of the inorganic particles may range from 0.01 parts by weight to 5 parts by weight, based on 100 parts by weight of the foamed sheet. Specifically, the content of the above inorganic particles may range from 0.05 to 5 parts by weight, from 0.08 to 4 parts by weight, or from 0.10 to 3 parts by weight.
The inorganic particles may be one or more selected from talc, mica, silica, diatomaceous earth, alumina, titanium oxide, zinc oxide, magnesium hydroxide, aluminum hydroxide, calcium hydroxide, potassium carbonate, calcium carbonate, magnesium carbonate, potassium sulfate, barium sulfate, sodium bicarbonate, and glass beads. Specifically, the inorganic particles may be selected from titanium oxide (TiO)2) One or more of Talc (Talc), Silica (Silica), and zirconia (ZrO 2). The inclusion of the inorganic particles as described above can reduce the cell size of the foamed sheet and increase the density.
For example, the composite sheet may have Barrier (Barrier) performance, hydrophilization function or water-repellent function, and the additive may include one or more functional additives selected from a thickener, a surfactant, a hydrophilization agent, a heat stabilizer, a water repellent, a pore size enlarging agent, an infrared ray attenuating agent, a plasticizer, a fire-retardant chemical, a pigment, an elastic polymer, an extrusion aid, an antioxidant, a nucleating agent, an air discharge preventing agent and an ultraviolet absorber. Specifically, the resin foam of the present invention may contain a thickener, a nucleating agent, a heat stabilizer, and a foaming agent.
The above thickener is not particularly limited, but pyromellitic dianhydride (PMDA) can be used in the present invention.
Examples of the nucleating agent include inorganic compounds such as talc, mica, silica, diatomaceous earth, alumina, titanium oxide, zinc oxide, magnesium hydroxide, aluminum hydroxide, calcium hydroxide, potassium carbonate, calcium carbonate, magnesium carbonate, potassium sulfate, barium sulfate, sodium hydrogen carbonate, and glass beads. Such a nucleating agent can impart functionality to the resin foam and play a role in reducing the price and the like. Specifically, Talc (Talc) may be used in the present invention. The nucleating agent described above may be mixed in the resin for extrusion foaming or added in the resin polymerization as described above.
The heat stabilizer may be an organic phosphorus compound or an inorganic phosphorus compound. For example, the above-mentioned organic or inorganic phosphorus compound may be phosphoric acid and organic esters thereof, phosphorous acid and organic esters thereof. For example, the heat stabilizer may be a commercially available one, and the heat stabilizer may be phosphoric acid, alkyl phosphate ester, or aryl phosphate ester. Specifically, the heat stabilizer in the present invention may be triphenyl phosphate, but is not limited thereto and may be used without limitation in a conventional range as long as the heat stability of the above resin foam can be improved.
Examples of the blowing agent include N2、CO2Physical blowing agents such as freon, butane, pentane, neopentane, hexane, isohexane, n-heptane, isoheptane and chloromethane, azodicarbonamide (azodicarbonamide), and P, P '-oxo (benzenesulfonylhydrazide) [ P, P' -oxy bis (phenyl sulfonyl hydrazide) ]]Chemical foaming agents such as N, N '-dinitrosopentamethylene tetramine (N, N' -dinitroso pentamethylene tetramine) compounds, and more specifically, CO can be used in the present invention2。
Also, the present invention provides a food container comprising the composite sheet as described above and having a crystallinity of 20% or more. Specifically, the food container has a structure including a receiving portion formed of the composite sheet.
According to one embodiment, the above food container may satisfy the following mathematical formula 3.
Mathematical formula 3: i T2-T1|≥10℃，
In the above-mentioned mathematical formula 3,
T1represents the outside surface temperature, T, of a food container measured when the food container is filled with water at 100 ℃ under a condition of a temperature of 20 ℃ and 1atm for one minute2The temperature of water in the food container measured when 100 ℃ water was filled in the food container at 20 ℃ and 1atm for one minute
As shown in the above equation 3, the food container of the present invention has a difference of 10 ℃ or more between the outside surface temperature and the inside water temperature of the food container measured after one minute of filling water at 100 ℃, has excellent heat insulation, and is easy to move because the outside surface temperature is low even if hot water is filled. The reason for this is that the air layer caused by the foaming in the composite sheet blocks heat.
According to one embodiment, the food container of the present invention comprises:
a food storage section having a recessed shape with an upper opening, the food storage section including a foamed sheet and a resin layer formed on one or both surfaces of the foamed sheet; and a lid portion having a shape corresponding to the upper opening portion of the food storage portion, the lid portion including a polyester or polypropylene resin layer and a resin layer formed on one or both surfaces of the polyester or polypropylene resin layer, wherein an upper surface of an edge portion of the food storage portion forming the upper opening portion and a lower surface of the lid portion are coated with the same resin or laminated (laminated) with a film layer.
As an example, the oxygen permeability of the food container of the present invention may be 50cc/m at a temperature of 23 ℃ and a relative humidity of 50%2And/24 h or less. Specifically, the oxygen permeability of the food container may be 0.1cc/m224h to 50cc/m2/24h、0.1cc/m224h to 30cc/m224h or 0.1cc/m224h to 5cc/m2And/24 h. The food container of the present invention has an oxygen permeability within the above range, and can prevent the food in the food container from being decomposed by reaction with oxygen, thereby facilitating storage of the food.
According to one embodiment, the food container includes a foamed sheet made of polyester resin; a vinyl alcohol coating layer; and a structure in which polyethylene resin layers are sequentially laminated, the cover portion including a polyester or nylon resin layer; a vinyl alcohol coating layer; and a structure in which polyethylene resin layers are sequentially laminated, wherein the polyethylene resin layer of the food storage section and the polyethylene resin layer of the lid section may be laminated to each other.
Specifically, in a state where the storage object is stored in the food storage unit, the lid portion is bonded to the food storage unit, and an internal space formed by bonding the food storage unit and the lid portion may be filled with nitrogen gas.
The food container is formed by passing the foamed sheet of the present invention through a heater so that the surface temperature of the sheet is 80 to 200 ℃, and then setting the temperature of a mold for container form formation to 140 to 200 ℃.
The present invention also provides a method for producing the composite sheet for food containers.
According to one embodiment, the preparation method of the present invention comprises: a step of preparing a foamed sheet by extrusion foaming of a polyester resin obtained by polymerizing an acid component and a diol component; forming a polyester resin layer on one or both surfaces of the foamed sheet; and a step of heating and pressing the foamed sheet on which the resin layer is formed to form a recessed shape having an upper opening.
The acid component contains one or more of terephthalic acid and terephthalic acid derivatives, and one or more of isophthalic acid, isophthalic acid derivatives, and phthalic anhydride,
the layer of one or more of the foamed sheet and the resin layer contains inorganic particles contained in the layer. For example, the foamed sheet and the resin layer may contain inorganic particles.
Specifically, in the step of preparing the polyester resin by polymerizing the acid component and the diol component, the acid component may necessarily contain a terephthalic acid derivative, and may further contain one or more selected from an isophthalic acid derivative and a phthalic acid derivative as the case may be. The diol component may contain an ethylene glycol derivative, and may contain one or more selected from 2-methyl-1, 3-propanediol (MP), neopentyl glycol (neopentylglycol), 1,2-propanediol (1,2-propanediol), diethylene glycol (diethylene glycol), and isosorbide (isosorbide) as the case may be
According to one embodiment, the prepared polyester resin may include 80 to 99 mol% of the repeating units derived from the terephthalic acid derivative and the ethylene glycol derivative, with respect to the total repeating units. Specifically, the repeating units derived from the terephthalic acid derivative and the ethylene glycol derivative may account for 80 to 99 mol%, 85 to 99 mol%, or 90 to 99 mol% relative to the total repeating units. More specifically, the repeating units derived from the terephthalic acid derivative and the ethylene glycol derivative may account for 92 to 99 mol%, or 96 to 98 mol%, relative to 100 mol% of the total repeating units. When the repeating units derived from the terephthalic acid derivative and the ethylene glycol derivative are contained in the above-mentioned amounts, the crystallinity of the foamed sheet can be adjusted to an appropriate range.
For example, in the above acid component, the repeating unit derived from one or more selected from isophthalic acid derivatives and phthalic acid derivatives may account for 1 to 10 mol% relative to the total repeating units. Specifically, the repeating unit derived from an isophthalic acid derivative or a phthalic acid derivative may account for 1 to 8 mol% or 2 to 4 mol% relative to the total repeating units.
In the diol component, the repeating units derived from one or more selected from the group consisting of 2-methyl-1, 3-propanediol (MP), neopentyl glycol (neopentylglycol), 1,2-propanediol (1,2-propanediol), diethylene glycol (diethylene glycol), and isosorbide (isoside) may account for 1 to 10 mol% of the total repeating units. Specifically, the repeating units derived from 2-methyl-1, 3-propanediol (2-methyl-1, 3-propanediol, MP), neopentyl glycol (neopentylglycol), 1,2-propanediol (1,2-propanediol), diethylene glycol (diethylene glycol), or isosorbide (isosorbide) may account for 1 to 8 mol%, or 2 to 4 mol%, relative to the total repeating units.
In the case where the acid component or the glycol component as described above is contained, the degree of freedom of the resin increases, so that the melting point of the foamed sheet is lowered, resulting in a decrease in the crystallinity of the foamed sheet, thereby preventing the food container from being hardened during thermoforming.
According to one embodiment, in the step of preparing the polyester resin, an isophthalic acid derivative or a phthalic acid derivative as an acid component may be mixed in an amount of 1 to 10 mol% with respect to the total of the acid component and the diol component. Specifically, an isophthalic acid derivative or a phthalic acid derivative as an acid component may be mixed in an amount of 1 to 8 mol%, or 2 to 4 mol% with respect to the total of the acid component and the diol component.
Further, in the step of preparing the polyester resin, 1 to 10 mol% of 2-methyl-1, 3-propanediol (2-methyl-1, 3-propanediol, MP), neopentyl glycol (neopentylglycol), 1,2-propanediol (1,2-pr opaneediol), diethylene glycol (diethylene glycol) or isosorbide (isosorbide) may be mixed as the diol component with respect to the entire acid component and diol component. Specifically, 1 to 8 mol%, or 2 to 4 mol% of 2-methyl-1, 3-propanediol (2-methyl-1, 3-propanediol, MP), neopentyl glycol (neopentyl glycol), 1,2-propanediol (1,2-propanediol), diethylene glycol (diethylene glycol), or isosorbide (isoside) may be mixed as the diol component with respect to the entire acid component and diol component.
According to one embodiment, the step of preparing the foamed sheet may include a foaming process of foaming the polyester resin to prepare a foam. The foaming step can be performed by various types of extruders. The foaming process is generally performed by bead foaming or extrusion foaming, preferably extrusion foaming is used. In the extrusion foaming, the resin melt is continuously extruded and foamed, so that the process steps can be simplified, mass production can be realized, cracks, particle damage and the like can be prevented from being generated between the microbeads during the microbead foaming, and excellent buckling strength and compression strength can be realized.
For example, in the step of preparing the foamed sheet, the foamed sheet may have a thickness of 0.5mm to 5 mm. Specifically, the thickness of the above foamed sheet may be 0.8mm to 4.0mm, 1.0mm to 3.5mm, more specifically, the thickness of the foamed sheet may be 1.0mm to 4.0mm or 1.3mm to 3.0 mm.
For example, in the step of preparing the foamed sheet of the present invention, additives in various forms may be added. The additives may be added in the fluid line or during the foaming process, as desired. Examples of the additive may have Barrier (Barrier) properties, hydrophilization functions, or water-repellent functions, and may include one or more functional additives selected from thickeners, surfactants, hydrophilizing agents, heat stabilizers, water-repellent agents, pore size enlarging agents, infrared attenuating agents, plasticizers, fire-retardant chemicals, pigments, elastic polymers, extrusion aids, antioxidants, nucleating agents, air discharge preventing agents, and ultraviolet absorbers. Specifically, in the method for producing a foam of the present invention, one or more of a thickener, a nucleating agent, a heat stabilizer, and a foaming agent may be added, and one or more of the above-listed functional additives may be further included.
For example, in the step of preparing the foamed sheet of the present invention, one or more functional additives selected from the group consisting of a thickener, a hydrophilizing agent, a heat stabilizer, a water repellent, a pore size enlarging agent, an infrared ray attenuating agent, a plasticizer, a fire-retardant chemical, a pigment, an elastic polymer, an extrusion aid, an antioxidant, a nucleating agent, an air discharge preventing agent, and an ultraviolet absorber may be added to the fluid connection line. Among additives required for preparing the foam, additives not introduced into the fluid connection line may be introduced into the extrusion process.
The thickener is not particularly limited, but pyromellitic dianhydride (PMDA), for example, can be used in the present invention.
Examples of the nucleating agent include inorganic compounds such as talc, mica, silica, diatomaceous earth, alumina, titanium oxide, zinc oxide, magnesium hydroxide, aluminum hydroxide, calcium hydroxide, potassium carbonate, calcium carbonate, magnesium carbonate, potassium sulfate, barium sulfate, sodium hydrogen carbonate, and glass beads. Such a nucleating agent can impart functionality to the resin foam and play a role in reducing the price and the like. Specifically, Talc (Talc) may be used in the present invention.
In preparing the foam, a master batch (master batch) is simultaneously charged with a resin solution and a nucleating agent to cause foaming. However, the nucleating agent to be charged is poor in dispersibility in the resin solution. Due to the low dispersibility of the nucleating agent, the size of cells is not uniform in the foaming process, and the content is not uniform due to process errors according to the situation. In order to improve the above phenomenon, in the present invention, inorganic particles (inorganic substance) may be added in advance in a polymerization step as a polyester resin production step to improve the dispersibility of the inorganic particles. The content of the inorganic particles ranges from 0.01 to 5 parts by weight with respect to 100 parts by weight of the foamed sheet. Specifically, the content of the above inorganic particles may range from 0.05 to 5 parts by weight, from 0.08 to 4 parts by weight, or from 0.10 to 3 parts by weight.
The heat stabilizer may be an organic phosphorus compound or an inorganic phosphorus compound. For example, the above-mentioned organic or inorganic phosphorus compound may be phosphoric acid and organic esters thereof, phosphorous acid and organic esters thereof. For example, the heat stabilizer may be a commercially available one, and the heat stabilizer may be phosphoric acid, alkyl phosphate ester, or aryl phosphate ester. Specifically, the heat stabilizer in the present invention may be triphenyl phosphate, but is not limited thereto and may be used without limitation in the conventional range as long as the heat stability of the above resin foamed sheet can be improved.
As an example of the above blowing agent, there is N2、CO2Physical blowing agents such as freon, butane, pentane, neopentane, hexane, isohexane, n-heptane, isoheptane and chloromethane, azodicarbonamide (azodicarbonamide), and P, P' -oxo (bisbenzenesulfonylhydrazide)[P,P'-oxy bis(benzene sulfonyl hydrazide)]Chemical foaming agents such as N, N '-dinitrosopentamethylene tetramine (N, N' -dinitroso pentamethylene tetramine) compounds, and more specifically, CO can be used in the present invention2。
The water repellent is not particularly limited, and examples thereof include silicones, epoxies, cyanoacrylates, polyvinyl acrylates, vinyl acetates, acrylates, chlorobutadiene, mixtures of polyurethane resins and polyester resins, mixtures of polyols and polyurethane resins, mixtures of acrylic polymers and polyurethane resins, and mixtures of polyimides and mixtures of cyanoacrylates and urethanes.
Further, the composite sheet prepared in the present invention is processed to prepare a food container. Specifically, after applying heat of 140 ℃ to 190 ℃ to the foamed sheet and the resin layer, the foamed sheet and the resin layer are molded by mechanical energy of a mold at a temperature of 80 ℃ to 200 ℃. The composite sheet of the present invention may be subjected to a deep drawing (deep drawing) of 7cm or more.
The present invention will be described in more detail below with reference to examples and experimental examples.
However, the following examples and experimental examples are only for illustrating the present invention, and the contents of the present invention are not limited to the following examples and experimental examples.
[ example 1 ]
Based on 100 parts by weight of the polyester resin, 0.5 part by weight of pyromellitic dianhydride, 0.5 part by weight of talc and 0.1 part by weight of Irganox (IRG 1010) were mixed, and the mixture was heated at 280 ℃. Thereafter, butane was added as a foaming agent to the first extruder, 3 parts by weight of butane was added based on 100 parts by weight of polyethylene terephthalate (PET) resin, and extrusion foaming was performed, thereby preparing a foamed sheet of polyester resin having a thickness of 2 mm.
Then, a resin coating layer was formed on the foamed sheet by extrusion coating with a molten polyethylene terephthalate resin using T-Die. Thereafter, the foamed sheet was heated and pressed at an average temperature ranging from 300 ℃ to 400 ℃ at a pressing speed of 4mm/min to prepare a composite sheet.
[ example 2 ]
0.5 parts by weight of pyromellitic dianhydride, 3 parts by weight of calcium carbonate having an average particle size of 2 μm, and 2 parts by weight of TiO were mixed based on 100 parts by weight of the polyester resin2And 0.1 part by weight of Irganox (IRG 1010) and heated at a temperature of 280 ℃ to prepare a resin melt. Thereafter, butane was added as a blowing agent to the first extruder, 3 parts by weight of butane based on 100 parts by weight of polyethylene terephthalate (PET) resin was added and extrusion foaming was performed, thereby preparing a density of 350kg/m3And a foamed layer having a thickness of 1.5 mm.
Then, 2 parts by weight of calcium carbonate having an average particle size of 0.5 μm and 2 parts by weight of TiO were mixed with 100 parts by weight of polyethylene terephthalate as a base material to the foamed sheet2The resin melt was prepared by heating at 280 ℃ and extrusion-coated with T-Die to form a resin coating layer.
[ COMPARATIVE EXAMPLE 1 ]
A composite sheet was produced in the same manner as in example 1, except that the resin coating layer on the above-described foamed sheet did not contain inorganic particles.
[ COMPARATIVE EXAMPLE 2 ]
A composite sheet was prepared in the same manner as in example 1, except that the crystallinity of the foamed sheet was controlled to 65%.
[ Experimental example 1: high temperature characteristics
The high temperature characteristics were measured using the composite sheets prepared in example 1, comparative example 1 and comparative example 2. The measurement conditions are as follows, and the measurement results are shown in Table 1.
When measuring the high temperature characteristics, each sample was put into an oven at a temperature of 150 ℃ and stored for 10 minutes. The volume of the sample before the sample was placed in the oven and the volume of the sample after 3 hours had passed in the oven were measured, and the amount of change was calculated.
[ TABLE 1 ]
| Volume change rate (%) | |
| Example 1 | 1.3 |
| Comparative example 1 | 6.2 |
| Comparative example 2 | 5.3 |
As can be seen from table 1, in example 1, the volume change rate at high temperature is significantly reduced as compared with comparative examples 1 and 2. From this, it was found that the composite sheet of the present invention is excellent in high-temperature stability.
[ Experimental example 2: heat insulation
The heat insulation properties were measured using the composite sheets prepared in example 1, comparative example 1, and comparative example 2.
In the measurement of the heat insulation property, 100 ℃ water was charged into a container, and after 5 minutes, the surface temperature outside the container and the water temperature inside the container were measured by an infrared thermometer, and the temperature difference was measured.
[ Experimental example 3: compressive Strength
When the compressive strength was measured, the maximum load was measured by a tensile strength tester at a predetermined speed (100 mm/min).
As can be seen from table 1, in example 1, the volume change rate at high temperature is significantly reduced as compared with comparative examples 1 and 2. From this, it was found that the composite sheet of the present invention is excellent in high-temperature stability.
[ Experimental example 4: processing characteristics
The processing characteristics were measured using the composite sheets prepared in example 1, comparative example 1 and comparative example 2. Specifically, each sample was cut into pieces of 20cm × 20 cm. And each cut sample was processed to a depth of 7 cm. After the processing, the appearance was observed to confirm the presence or absence of defects.
It was confirmed that no appearance fracture or cracking was observed in example 1, but appearance fracture was observed in comparative example 1 and partial fracture occurred in comparative example 2. From this, it is understood that the composite sheet of the present invention is excellent in processability.
Industrial applicability
The composite sheet for food containers of the present invention can satisfy both high heat resistance and excellent processability by controlling the crystallinity of a foamed sheet of a polyester resin and the crystallinity of a resin layer formed on the foamed sheet.
Claims (15)
1. A composite sheet for a food container, comprising:
a foamed sheet of polyester resin; and
a polyester resin layer formed on one or both surfaces of the foamed sheet,
one or more layers of the foamed sheet and the resin layer contain inorganic particles contained in the layer,
the content of the inorganic particles is in the range of 0.01 to 10 parts by weight based on 100 parts by weight of one or more layers of the foamed sheet and the resin layer,
the average size of the inorganic particles is 10 μm or less.
2. The composite sheet for food containers as claimed in claim 1, wherein the inorganic particles comprise talc or CaCO3、TiO2And SiO or more.
3. The composite sheet for food containers as claimed in claim 1, wherein the crystallinity of the polyester resin foamed sheet and the crystallinity of the polyester resin layer are 5% to 40%.
4. The composite sheet for food containers as claimed in claim 1, wherein the foamed sheet of polyester resin and the polyester resin layer are formed of polyethylene terephthalate resin.
5. The composite sheet for food containers as set forth in claim 1,
the above composite sheet satisfies the following mathematical formula 1:
mathematical formula 1: v is more than or equal to 50%1-V0|/V0×100≤300％；
In the above-mentioned mathematical formula 1,
V0represents the volume (mm) of the composite sheet before exposure to a temperature of 200 ℃ for 30 seconds3)，
V1Represents the volume of the composite sheet after 30 seconds of exposure at a temperature of 200 ℃ in units of (mm)3)。
6. The composite sheet for food containers as claimed in claim 1, wherein the impact strength at-10 ℃ according to ASTM D256 of the composite sheet is 20KJ/m2Or more.
7. The composite sheet for food containers as set forth in claim 1,
the foamed sheet has an average cell size of 10 to 690 μm,
and the composite sheet for food containers satisfies the following numerical formula 2,
mathematical formula 2: i Vb-Va|/Va×100≤10％；
In the above-mentioned mathematical formula 2,
Vathe volume (cm) of the food container before the 500g ball was allowed to freely fall from the height of 30cm to the composite sheet3)，
VbThe volume (cm) of the food container after the 500g ball was freely dropped from a height of 30cm to the composite sheet3)。
8. A food container, characterized in that,
comprising the composite sheet of any one of claims 1 to 7,
the crystallinity is 20% or more.
9. Food product container according to claim 8,
the following mathematical formula 3 is satisfied,
mathematical formula 3: i T2-T1|≥10℃，
In the above-mentioned mathematical formula 3,
T1represents the outside surface temperature of the food container measured when water of 100 ℃ is filled in the food container at a temperature of 20 ℃ and 1atm for one minute,
T2the temperature of water in the food container measured when 100 ℃ water was filled in the food container at a temperature of 20 ℃ and 1atm and one minute passed is shown.
10. Food product container according to claim 8,
the food container includes:
a food storage section having a recessed shape with an upper opening, the food storage section including a foamed sheet and a resin layer formed on one or both surfaces of the foamed sheet; and
a lid part having a shape corresponding to the upper opening of the food storage part and including a polyester or polypropylene resin layer and a resin layer formed on one or both surfaces of the polyester or polypropylene resin layer,
the upper surface of the edge portion of the food storage section forming the upper opening and the lower surface of the lid section are coated with the same resin.
11. Food product container according to claim 10,
the lid portion is bonded to the food storage portion in a state where the food storage portion stores the storage object therein, and an inner space formed by bonding the food storage portion to the lid portion is filled with nitrogen gas.
12. A method for preparing a composite sheet for a food container,
the method comprises the following steps:
a step of preparing a foamed sheet by extrusion foaming of a polyester resin obtained by polymerizing an acid component and a diol component;
forming a polyester resin layer on one or both surfaces of the foamed sheet; and
heating and pressing the foamed sheet having the resin layer formed thereon to form a recessed shape having an upper opening,
the acid component contains one or more of terephthalic acid and terephthalic acid derivatives, and one or more of isophthalic acid, isophthalic acid derivatives, and phthalic anhydride,
the layer containing inorganic particles contained in the layer is one or more of the foamed sheet and the resin layer.
13. The method for producing a composite sheet for a food container according to claim 12, wherein the content of one or more of isophthalic acid, an isophthalic acid derivative, and phthalic anhydride is 1 to 10 mol% based on the total amount of the acid component and the glycol component.
14. The method for producing a composite sheet for a food container according to claim 12, wherein the diol component contains one or more of ethylene glycol, 2-methyl-1, 3-propanediol, neopentyl glycol, 1,2-propanediol, diethylene glycol, and isosorbide.
15. The method of producing a composite sheet for a food container according to claim 12, wherein the polyester resin forming the one or more layers of the foamed sheet and the resin layer contains 0.01 to 5 parts by weight of the inorganic particles based on 100 parts by weight of the resin.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| KR10-2017-0174316 | 2017-12-18 | ||
| KR20170174316 | 2017-12-18 | ||
| PCT/KR2018/016161 WO2019124948A1 (en) | 2017-12-18 | 2018-12-18 | Composite sheet having excellent heat resistance and processability for food container and manufacturing method therefor |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN110612209A true CN110612209A (en) | 2019-12-24 |
| CN110612209B CN110612209B (en) | 2021-12-31 |
Family
ID=66994135
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201880029022.7A Active CN110612209B (en) | 2017-12-18 | 2018-12-18 | Composite sheet for food container having excellent heat resistance and processability, and method for producing same |
Country Status (4)
| Country | Link |
|---|---|
| JP (2) | JP2020505247A (en) |
| KR (1) | KR102319817B1 (en) |
| CN (1) | CN110612209B (en) |
| WO (1) | WO2019124948A1 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR102175971B1 (en) * | 2019-06-28 | 2020-11-10 | 주식회사 휴비스 | A molded foam article having different cell sizes depending on the part, package container containing the same, and preparation method of the molded foam article |
| KR102285935B1 (en) * | 2019-11-25 | 2021-08-05 | 주식회사 에스폴리텍 | Thermoplastic foam sheet |
| KR102443537B1 (en) * | 2020-04-21 | 2022-09-16 | 주식회사 휴비스 | Polyester foam sheet controlled equivalent of carboxyl end group |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2002284868A (en) * | 2001-03-27 | 2002-10-03 | Toray Ind Inc | Process for preparation of poly(butylene terephthalate) |
| US20050043419A1 (en) * | 2003-08-18 | 2005-02-24 | Saehn Industries Incorporation | Method for producing foamed products based on aromatic polyester resin with low melting point |
| KR100589081B1 (en) * | 1998-09-25 | 2006-06-13 | 신코 리세르체 에스.피.에이. | Polyester resin foamed sheets |
| WO2008043646A1 (en) * | 2006-10-13 | 2008-04-17 | Cryovac, Inc. | Heat-resistant molded foam articles and process for their manufacture |
Family Cites Families (15)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS58193236A (en) * | 1982-04-28 | 1983-11-10 | 大日本印刷株式会社 | Germless packing method for acidic food and its device |
| JPS58193235A (en) * | 1982-04-28 | 1983-11-10 | 大日本印刷株式会社 | Germless packing method for acidic food and its device |
| JPH0698982B2 (en) * | 1989-09-25 | 1994-12-07 | 積水化成品工業株式会社 | Food container |
| JP3179591B2 (en) * | 1992-09-24 | 2001-06-25 | 出光石油化学株式会社 | Food packaging method |
| ITMI991139A1 (en) * | 1999-05-24 | 2000-11-24 | Sinco Ricerche Spa | BI-ORIENTED EXPANDED FILM IN POLYESTER RESIN |
| JP4518353B2 (en) | 1999-11-30 | 2010-08-04 | 株式会社ジェイエスピー | Laminated foam for thermoforming |
| JP4714362B2 (en) * | 2001-03-26 | 2011-06-29 | 大阪瓦斯株式会社 | Low temperature molding material |
| EP1486431A4 (en) * | 2002-02-21 | 2009-05-06 | Nissei Kk | Tightly covered container |
| US7252866B2 (en) | 2002-12-20 | 2007-08-07 | Nova Chemicals Inc. | Thermoplastic film for a disposable container made of expandable thermoplastic particles |
| JP4733452B2 (en) * | 2005-07-15 | 2011-07-27 | 出光ユニテック株式会社 | Package |
| KR20090091279A (en) * | 2006-12-22 | 2009-08-27 | 유니띠까 가부시키가이샤 | Biodegradable polyester resin composition, and molded body, foamed body and molded container obtained from the biodegradable polyester resin composition |
| JP5533515B2 (en) | 2010-09-30 | 2014-06-25 | 東洋製罐株式会社 | Polyester expanded foam container |
| KR20120058347A (en) | 2010-11-29 | 2012-06-07 | 현대자동차주식회사 | Thermo plastic complex for stiffener and Preparing method thereof |
| DE102015008554A1 (en) * | 2015-07-07 | 2017-01-12 | Klöckner Pentaplast Gmbh | Multilayer polymer film and multipack produced therefrom |
| US10696012B2 (en) * | 2015-08-13 | 2020-06-30 | Huvis Corporation | Composite of multilayer structure comprising polyester foam and polyester resin layer, and use thereof |
-
2018
- 2018-12-18 WO PCT/KR2018/016161 patent/WO2019124948A1/en active Application Filing
- 2018-12-18 JP JP2019517000A patent/JP2020505247A/en active Pending
- 2018-12-18 CN CN201880029022.7A patent/CN110612209B/en active Active
- 2018-12-18 KR KR1020180164412A patent/KR102319817B1/en active IP Right Grant
-
2020
- 2020-12-24 JP JP2020215439A patent/JP2021062622A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100589081B1 (en) * | 1998-09-25 | 2006-06-13 | 신코 리세르체 에스.피.에이. | Polyester resin foamed sheets |
| JP2002284868A (en) * | 2001-03-27 | 2002-10-03 | Toray Ind Inc | Process for preparation of poly(butylene terephthalate) |
| US20050043419A1 (en) * | 2003-08-18 | 2005-02-24 | Saehn Industries Incorporation | Method for producing foamed products based on aromatic polyester resin with low melting point |
| WO2008043646A1 (en) * | 2006-10-13 | 2008-04-17 | Cryovac, Inc. | Heat-resistant molded foam articles and process for their manufacture |
Also Published As
| Publication number | Publication date |
|---|---|
| CN110612209B (en) | 2021-12-31 |
| JP2020505247A (en) | 2020-02-20 |
| WO2019124948A1 (en) | 2019-06-27 |
| KR20190073306A (en) | 2019-06-26 |
| JP2021062622A (en) | 2021-04-22 |
| KR102319817B1 (en) | 2021-11-02 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN110612209B (en) | Composite sheet for food container having excellent heat resistance and processability, and method for producing same | |
| KR102005292B1 (en) | Foam sheet containing skin layer, preparation method thereof, and Food container comprising the same | |
| KR102027428B1 (en) | Foam sheet with excellent thrmoforming, and preparation method thereof | |
| JP6838145B2 (en) | A molded product containing a gas barrier layer, a packaging container containing the molded product, and a method for manufacturing the molded product. | |
| KR102160456B1 (en) | Excellent moldability foam sheet, preparation method thereof, and food container using the same | |
| KR101997619B1 (en) | Foam sheet containing inorganic particle, and preparation method thereof | |
| KR101778629B1 (en) | Eco-friendly heat resisting material having excellent dimension stability, manufacturing method of the same and packaging container comprising the same | |
| KR102160454B1 (en) | Excellent heat resistance foam sheet, preparation method thereof, and food container comprising the same | |
| JP6901553B2 (en) | Effervescent sheet containing calcium carbonate, its manufacturing method and food container containing it | |
| JP4583160B2 (en) | Biodegradable laminated foam sheet and molded body thereof | |
| CN111587270B (en) | Foamed sheet having excellent thermoformability and method for producing same | |
| CN111886185A (en) | Packaging container comprising a lidding film and method for the production thereof | |
| KR102190657B1 (en) | Foam sheet comprising calcium carbonate, preparing method for the same, and food container containing the same | |
| JP7213817B2 (en) | Food packaging container and manufacturing method thereof | |
| CN111629895A (en) | Foamed sheet including surface layer, method of preparing the same, and food container including the same | |
| KR102160455B1 (en) | Foam sheet having an excellent workability, preparation method thereof, and food container comprising the same | |
| KR101985365B1 (en) | Food packaging container with excellent elongation, and preparation method thereof | |
| KR101967808B1 (en) | Foam sheet containing inorganic particle, and preparation method thereof | |
| KR101976434B1 (en) | Foam sheet containing inorganic particle and carbon black, and preparation method thereof | |
| KR20230078138A (en) | Foam sheet having improved contraction percentage | |
| KR20230078139A (en) | Foam sheet having improved surface roughness | |
| KR20210128696A (en) | Polyester resin chip, polyester foam sheet and manufacturing method of the same |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |