JP2007217024A - Heat insulating paper container, and method of producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a new heat insulating paper container which has foam larger than that of a low-melting thermoplastic synthetic resin film, and exerts sufficient heat insulation effect, and to provide a method of producing the same. <P>SOLUTION: The heat insulating paper container is formed of a container body member 1 and a bottom plate member 2. In production of the heat insulating paper container, a high-melting thermoplastic synthetic resin film 4 is laminated on an inner wall surface of base paper 3 of the container body member 1 and the bottom plate member 2, and the low-melting thermoplastic resin film 5 is laminated on an outer wall surface of the base paper 3 of the container body member 1, followed by subjecting the low-melting thermoplastic resin film 5 to heat treatment and foaming. Herein the low-melting thermoplastic synthetic resin film 5 is obtained by mixing a low-density polyethylene and a copolymer of ethylene-α olefine. The method of producing the heat insulating paper container is also provided. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a heat-insulating paper container in which a low-melting thermoplastic synthetic resin film is laminated on the surface of a base paper of a container body member, and the low-melting thermoplastic synthetic resin film is foamed, and a method for producing the same.

A heat insulating paper container for laminating a low density polyethylene film on the surface of the base paper of the container body member and heating and foaming the low density polyethylene film and its manufacturing method are known (for example, Patent Document 1).
Japanese Patent No. 3408156

In the prior example of the above-mentioned Patent Document 1, a synchronized ink that forms a smooth printing surface in synchronization with foaming is applied to the surface of a thermoplastic synthetic resin film having a low melting point on the surface of the thermoplastic synthetic resin film after foaming. Therefore, a good heat-insulating paper container without foaming is obtained, which foams substantially equally over the entire surface of the container body member.
However, in this known prior art, there is a problem that a sufficient thermoplastic synthetic resin film cannot be foamed and a sufficient heat insulating effect cannot be obtained.
In view of the above problems, the present invention provides a novel heat-insulating paper container and a method for producing the same, in which larger foaming of a low-melting-point thermoplastic synthetic resin film is obtained and a more sufficient heat-insulating effect is obtained. .

Therefore, in the present invention, a container body member and a bottom plate member are formed, and a high melting point thermoplastic synthetic resin film is laminated on the inner wall surface of the base material of the container body member and the bottom plate member, and the outer wall surface of the base paper of the container body member A low-melting thermoplastic synthetic resin film is laminated to a heat-insulating paper container which is foamed by heat-treating the low-melting thermoplastic synthetic resin film, the low-melting thermoplastic synthetic resin Provided is a heat insulating paper container characterized in that the film is formed by mixing low density polyethylene and a copolymer of ethylene-α-olefin.
The mixing ratio of the low-density polyethylene and the ethylene-α-olefin copolymer is 70:30 to 90:10, preferably 80:20.
A printing surface is formed on the surface of the low-melting-point thermoplastic synthetic resin film.
The printing surface is composed of a printing surface coated with white ink as a base and a printing surface printed on the upper surface thereof.
The printed surface is formed by applying a synchronized ink that forms a smooth printed surface in synchronization with foaming on the surface of a low-melting thermoplastic synthetic resin film after foaming.
A printing surface is provided between the base paper and the low-melting-point thermoplastic synthetic resin film.
The density of the low-density polyethylene constituting the low-melting thermoplastic synthetic resin film is 0.910 to 0.924 Kg / m ³ , preferably 0.910 to 0.920 Kg / m ³ , and MFR (melt mass flow) (Rate) is 2 to 15 g / 10 min, preferably 3 to 10 g / 10 min, and the density of the ethylene-α-olefin copolymer is 0.885 to 0.924 Kg / m ³ , preferably 0.885. 0.990 Kg / m ³ , MFR 2-15 g / 10 min, preferably 3-10 g / 10 min, and film thickness 60 μm-80 μm, preferably 65 μm-70 μm.
The water content of the base paper is 7.2% to 8.8%, preferably 7.5% to 8.5%.

Next, in the present invention, a container body member and a bottom plate member are formed, and a thermoplastic synthetic resin film having a high melting point is laminated on the inner wall surface of the base material of the container body member and the bottom plate member, and the outer wall surface of the base material of the container body member A low-melting point thermoplastic synthetic resin film is laminated, and the low-melting point thermoplastic synthetic resin film is heat-treated so as to foam the low-melting point thermoplastic synthetic resin film. Provided is a method for producing a heat insulating paper container, wherein the resin film is formed by mixing low density polyethylene and a copolymer of ethylene-α-olefin.
The mixing ratio of the low-density polyethylene and the ethylene-α-olefin copolymer is in the range of 70:30 to 90:10, and preferably the mixing ratio is 80:20.
A printed surface is formed on the surface of the low-melting thermoplastic synthetic resin film, and the low-melting thermoplastic synthetic resin film having the printed surface is heat-treated to foam.
The printing surface includes a printing surface coated with white ink as a base and a printing surface coated on the upper surface thereof.
The printed surface is formed by applying a synchronized ink that forms a smooth printed surface in synchronization with foaming on the surface of a low-melting thermoplastic synthetic resin film after foaming.
A printing surface is provided between the base paper and the low-melting-point thermoplastic synthetic resin film.
The density of the low-density polyethylene constituting the low-melting thermoplastic synthetic resin film is 0.910 to 0.924 Kg / m ³ , preferably 0.910 to 0.920 Kg / m ³ , and MFR (melt mass flow) (Rate) is 2 to 15 g / 10 min, preferably 3 to 10 g / 10 min, and the density of the ethylene-α-olefin copolymer is 0.885 to 0.924 Kg / m ³ , preferably 0.885. 0.990 Kg / m ³ , MFR 2-15 g / 10 min, preferably 3-10 g / 10 min, and film thickness 60 μm-80 μm, preferably 65 μm-70 μm.
The water content of the base paper is 7.2 to 8.8%, preferably 7.5% to 8.5%.
The heat treatment is performed at a high temperature of 115 ° C. to 130 ° C. for 3 minutes to 8 minutes, preferably 5 to 6 minutes at a high temperature of 120 ° C. to 125 ° C.
The heat insulating paper container is transferred and heated while rotating on a conveyor.

  According to the heat insulating paper container of the present invention and the method for manufacturing the same, the container body member and the bottom plate member are laminated, and the high-melting point thermoplastic synthetic resin film is laminated on the inner wall surface of the base material of the container body member and the bottom plate member. A low-melting point thermoplastic synthetic resin film is laminated on the outer wall surface of the base paper of the container body member, and this low-melting point thermoplastic synthetic resin film is a heat-insulating paper container that is foamed by heat treatment, Since the low-melting thermoplastic synthetic resin film is composed of a mixture of low-density polyethylene and ethylene-α-olefin copolymer, larger foaming of the low-melting thermoplastic synthetic resin film is obtained, There is an effect that a heat insulating paper container having a more sufficient heat insulating effect can be obtained.

  Further, according to the heat insulating paper container of the present invention and the method for manufacturing the same, since the printing surface is provided on the surface of the thermoplastic synthetic resin film, even if the container is highly foamed and more thermally insulating, a high cosmetic There is an effect that a heat-insulating paper container having a good property can be obtained. Furthermore, since the printing surface is coated with a synchronous ink that forms a smooth printing surface in synchronization with foaming, the container surface is a smooth printing surface and a heat-insulating paper container excellent in cosmetics. Is effective.

Details of the present invention will be described below with reference to embodiments shown in the drawings.
FIG. 1 shows a cross-sectional view of a basic embodiment without a printing surface on the surface of a low-melting thermoplastic synthetic resin film, and FIG. 2 shows a cross-sectional view of an embodiment with a printing surface. FIG. 6 to FIG. 6 show enlarged sectional views of essential parts of the respective embodiments.
The heat insulating paper container of the present invention comprises a container body member 1 and a bottom plate member 2, and the container body member 1 and the bottom plate member 2 have a coupling structure similar to that of a known paper cup-shaped container.

In the container body member 1, a high-melting point thermoplastic synthetic resin film 4 is laminated on the inner wall surface of the base paper 3, and a low-melting point thermoplastic synthetic resin film 5 is laminated on the outer wall surface of the base paper 3.
The base paper 3 has a basis weight of 200 g to 400 g / m ² and a moisture content of 7.2 to 8.8%, preferably 7.5 to 8.5%. When the moisture content is 7.1% or less, when heat-treated, the low-melting thermoplastic synthetic resin film described later cannot be sufficiently foamed when the moisture content is low, and the moisture content is 8.9% or more. The amount of moisture in the thermoplastic synthetic resin film with a low melting point is too large, and the container surface is poorly decorated. When the container is molded, the joint between the body member and the bottom member buckles during the curling process. Wrinkles are likely to be defective.
The thermoplastic synthetic resin film having a high melting point on the inner wall surface is not different from the thermoplastic synthetic resin film used in a known heat insulating paper container.

In the present invention, the low melting point thermoplastic synthetic resin film laminated on the outer wall surface of the base paper 3 is composed of a mixture of a low melting point polyethylene and an ethylene-α-olefin copolymer. .
In order to make the resin soft and easy to stretch, the ethylene-α olefin copolymer is mixed with low melting point polyethylene, but the melt tension of the resin itself is not straight due to the molecular structure. Since there is no long chain branching in the side chain on the chain, there is no entanglement between molecules and it is easy to break, but low-melting polyethylene has long chain branching in the molecular structure and many entanglements between molecules, resulting in a high melt tension. Even if foamed, the cell is hard to break. Therefore, by mixing an ethylene-α-olefin copolymer with a low melting point polyethylene, a heat-treated resin can be obtained by heat treatment. The low melting point polyethylene is required to have a mixing ratio of 70:30 to 90:10 with the ethylene-α-olefin copolymer, and preferably 80:20 is the appearance and foaming of the container surface. It turns out that it is the most excellent in the degree.

The polymerization catalyst for the ethylene-α-olefin copolymer may be a Ziegler-Natta catalyst (multi-site catalyst) or a metallocene catalyst (single-site catalyst), but is preferably polymerized using a metallocene catalyst. (The polymerization catalyst of the copolymer of ethylene-α-olefin in the examples described later uses a metallocene catalyst and the α-olefin has 6 to 1 carbon atoms.) The Ziegler-Natta catalyst product has a low molecular weight. However, there are many α-olefins and there is a part with a high density, and the melting point is higher than that of the metallocene catalyst product. However, the metallocene catalyst product has a uniform distribution of α-olefin in the chain, and the crystals are earlier because there are few crystals. Melts and has a lower melting point than Ziegler-Natta catalyst products, so it easily foams.
Then, the density of the low density polyethylene constituting the low melting thermoplastic synthetic resin film is 0.910~0.924Kg / ^{m 3,} preferably 0.910~0.920Kg / ^{m 3,} MFR ( Melt mass flow rate) is 2 to 15 g / 10 min, preferably 3 to 10 g / 10 min, and the density of the ethylene-α-olefin copolymer is 0.885 to 0.924 Kg / m ³ , preferably 0 0.85 to 0.910 Kg / m ³ , MFR 2 to 15 g / 10 min, preferably 3 to 10 g / 10 min, and film thickness 60 μm to 80 μm, preferably 65 μm to 70 μm.

  2, 4 and 5 show examples in which printing surfaces 6 and 7 are provided on the surface of a low-melting thermoplastic synthetic resin film. The printing surfaces 6 and 7 are provided by applying a tuning ink that forms a smooth printing surface in synchronism with the foaming of the low-melting thermoplastic synthetic resin film. Synchronizing with foaming means that when a thermoplastic resin film with a low melting point is foamed, it foams in the diameter direction of the container and simultaneously expands in the surface area direction. It is to be.

The embodiment shown in FIGS. 2 and 4 shows a case where the outer surface of the container is provided with a printing surface 6 on which the design of the container surface is printed. In the embodiment shown in FIG. A printed surface on which white ink as a base is applied is shown, and a printed surface 7 on which the design of the container surface is printed is provided on the printed surface. Next, in FIG. 6, a printing surface 8 is provided between the base paper 3 and the low-melting-point thermoplastic synthetic resin film 5, and this printing surface 8 does not have to be a synchronous ink.
FIG. 3 to FIG. 6 show the high-foamed thermoplastic synthetic resin film having a low melting point by heat treatment from the original form of each example.

The tuned ink is composed of a colorant, a resin, a solvent and an auxiliary agent, and the white ink has the above-mentioned ratio of the colorant 20 to 35%, the resin 15 to 30%, the solvent 25 to 50%, and the auxiliary agent 1 to 5%. The colored ink is also composed of a colorant, a resin, a solvent and an auxiliary agent, and the above ratio is 5 to 20% for the colorant, 5 to 30% for the resin, 50 to 85% for the solvent, and 1 to 5% for the auxiliary agent. .
The colorant of the white ink is an inorganic pigment (titanium oxide), and the resin content is a vinyl chloride system (copolymer of vinyl chloride and vinyl acetate) and a urethane system (polymerization of polyester or polyether and diisocyanate). Product), urethane (polyester or polyether and diisocyanate polymer), nitrocellulose (nitrified cotton: nitrated ester of cellulose) and polyamide (condensate of dimer acid and polyamine), polyamide (Condensate of dimer acid and polyamine), solvent is ester (ethyl acetate, propyl acetate, butyl acetate), alcohol (isopropyl alcohol, butanol), ketone (methyl ethyl ketone, methyl isobutyl ketone), aliphatic Hydrocarbon (n-hexane, n-heptane), aroma Hydrocarbon (toluene, xylene) is one or two or more combinations of. The auxiliary agents are polyethylene wax, stabilizers, lubricants, antistatic agents, and antioxidants.

  Next, the colorant of the colored ink is mainly an organic pigment (azo, phthalocyanine, dioxazine, but black (carbon black) and gold-silver (aluminum powder) are inorganic pigments), and the resin content is vinyl acetate ( A mixture of vinyl chloride and vinyl acetate) and urethane (polyester or polyether and diisocyanate polymer), nitrocellulose (nitrified cotton: cellulose nitrate ester) and polyamide (dimer acid and polyamine) Condensate), solvent is ester (ethyl acetate, propyl acetate, butyl acetate), alcohol ((isopropyl alcohol, butanol), ketone (methyl ethyl ketone, methyl isobutyl ketone), aliphatic hydrocarbon (N-hexane, n-heptane), aromatic hydrocarbons (toluene, xylene) One or a combination of two or more hydrocarbons (toluene, xylene), and auxiliary agents are polyethylene wax, stabilizers, lubricants, antistatic agents, antioxidants It is.

  The method for producing a heat insulating paper container according to the present invention comprises heat-treating the raw material of the heat insulating paper container having the above-described structure to produce a low-melting-point thermoplastic synthetic resin film (a copolymer of low-density polyethylene and ethylene-α-olefin). The heating method is infrared (wavelength 0.74 μm to 1000 μm) (more specifically near infrared 0.74 μm to 3 μm, far infrared 3 μm to 1000 μm), halogen lamp, hot air blow (high wind pressure) , By one or a combination of two or more of gas heating. This heat treatment is performed at a high temperature of 115 ° C. to 130 ° C. for 3 minutes to 8 minutes, preferably 5 minutes 30 seconds to 6 minutes. Preferably, the heat insulating paper container is transferred and heated while rotating on a conveyor.

Sample materials to be described later were constructed using the following three types of resins a to c as thermoplastic synthetic resin films having a low melting point, and the sample materials were foamed by overheating, and the results were compared. Here, the low-density polyethylene is called LDPE, the high-density polyethylene is called HDPE, and the ethylene-α olefin copolymer (metallocene catalyst) is called m-LLDPE.
a. LDPE (MFR 8g / 10min, density 0.918Kg / m ³ )
b. m-LLDPE (MFR 10 g / 10 min, density 0.902 Kg / m ³ )
c. Current LDPE (MFR14g / 10min, density 0.918Kg / m ³ )
The following 6 items A to F without a printing surface were prepared as sample materials.
A. Resin a / Base paper 300 g / m ² / HDPE (MFR 6.5 g / 10 min, density 0.940 Kg / m ³ ) 40 μm
B. Resin b / Base paper 300 g / m ² / HDPE (MFR 6.5 g / 10 min, density 0.940 Kg / m ³ ) 40 μm
C. Resin a: b = 20: 80 / Base paper 300 g / m ² / HDPE (MFR 6.5 g / 10 min, density 0.940 Kg / m ³ ) 40 μm
D. Resin a: b = 50: 50 / Base paper 300 g / m ² / HDPE (MFR 6.5 g / 10 min, density 0.940 Kg / m ³ ) 40 μm
E. Resin a: b = 80: 20 / Base paper 300 g / m ² / HDPE (MFR 6.5 g / 10 min, density 0.940 Kg / m ³ ) 40 μm
F. Resin c / Base paper 300 g / m ² / HDPE (MFR 6.5 g / 10 min, density 0.940 Kg / m ³ ) 40 μm
These sample materials were allowed to stand in an oven at 120 ° C. for 3 minutes and 40 seconds as foaming conditions, then taken out and cooled to room temperature in air. Two types of resin film thicknesses of 65 μm and 90 μm were prepared and tested as sample materials. As the evaluation method, the surface appearance after foaming was visually observed, and there was almost no large unevenness and Δ partially uneven, and the results shown in the following table were obtained. As can be seen from this result, the resin a: b = 80: 20 was the best result.

  5 each of the current Patent No. 3408156 product (the sample F is cup-molded with a resin thickness of 65 μm) and the heat insulating paper container of the present invention (the sample E is cup-molded with a resin thickness of 65 μm). Table 2 shows the average values of the results of molding and test superheating foaming (125 ° C., 3 minutes 20 seconds).

ここで体感温度とは、カップに熱湯を投入し、１分後手で持っていられる時間（秒）。
表面温度とは、カップに熱湯を投入し、１分後の温度を表面温度計で測定した温度（℃）。
この表から理解できる通り、発泡樹脂厚み、断熱性、美粧性の比較をしたが、現行製品に比し、本発明品が発泡樹脂厚み、断熱性に優位さが認められた。

Here, the perceived temperature is the time (seconds) that hot water is poured into the cup and held for 1 minute later.
The surface temperature is a temperature (° C.) obtained by putting hot water into a cup and measuring the temperature after 1 minute with a surface thermometer.
As can be understood from this table, the thickness of the foamed resin, the heat insulating properties, and the cosmetics were compared, but the products of the present invention were found superior in the thickness of the foamed resin and the heat insulating properties as compared with the current products.

Next, a test cup A in which a resin film of LDPE: m-LLDPE = 80: 20 is laminated on a base paper 300 g / m ² and printed in white, and a resin film of LDPE: m-LLDPE = 80: 20 are also used in base paper 320 g / m. ² laminated white printed a test cup B and five by one molding, respectively, an ambient temperature 125 ° C., foaming resin thickness of a cup foamed over 6 min foaming time, thermal insulation, the beautification of measure. The average value is as shown in Table 3 below.

ここで体感温度とは、カップに熱湯を投入し、１分後手で持っていられる時間（秒）。
表面温度とは、カップに熱湯を投入し、１分後の温度を表面温度計で測定した温度（℃）。
この表から理解できる通り、本発明断熱性紙製容器は、大きな発泡と高い断熱性を有する製品となった。

Here, the perceived temperature is the time (seconds) that hot water is poured into the cup and held for 1 minute later.
The surface temperature is a temperature (° C.) obtained by putting hot water into a cup and measuring the temperature after 1 minute with a surface thermometer.
As can be understood from this table, the heat-insulating paper container of the present invention became a product having large foaming and high heat insulating properties.

It is sectional drawing which shows the fundamental Example without the printing surface of the heat-insulating paper container of this invention. It is sectional drawing of the Example which has a printing surface on the surface of the heat insulating paper container of this invention. It is an expanded sectional view of the principal part of the Example shown in FIG. It is an expanded sectional view of the principal part of the Example shown in FIG. It is an expanded sectional view of the Example which has a printing surface on the base printing surface of a white background. It is sectional drawing of the Example which provided the printing surface between the base paper and the low-melting-point thermoplastic synthetic resin film.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Container body member 2 Bottom plate member 3 Base paper 4 High-melting point thermoplastic synthetic resin film 5 Low-melting point thermoplastic synthetic resin film 6, 7, 8 Printing surface

Claims (18)

  It consists of a container body member and a bottom plate member. A thermoplastic synthetic resin film having a high melting point is laminated on the inner wall surface of the base material of the container body member and the bottom plate member, and a low melting point thermoplastic synthesis is performed on the outer wall surface of the base paper of the container body member. A heat-insulating paper container in which a resin film is laminated and this low-melting thermoplastic synthetic resin film is foamed by heat treatment, wherein the low-melting thermoplastic synthetic resin film comprises low-density polyethylene and ethylene -A heat insulating paper container characterized by being mixed with an α-olefin copolymer.   The heat-insulating paper container according to claim 1, wherein the mixing ratio of the low-density polyethylene and the ethylene-α-olefin copolymer is in the range of 70:30 to 90:10.   The heat-insulating paper container according to claim 1 or 2, wherein a printed surface is formed on the surface of the low-melting thermoplastic synthetic resin film.   The heat-insulating paper container according to claim 3, wherein the printed surface comprises a printed surface coated with white ink as a base and a printed surface printed on the upper surface.   5. The heat insulating paper product according to claim 3, wherein the printed surface is coated with a synchronized ink that forms a smooth printed surface in synchronization with foaming on the surface of the low-melting thermoplastic synthetic resin film after foaming. container.   The heat-insulating paper container according to claim 1 or 2, wherein a printing surface is provided between the base paper and a low-melting thermoplastic synthetic resin film. The low-density polyethylene constituting the low-melting-point thermoplastic synthetic resin film has a density of 0.910 to 0.924 Kg / m ³ , an MFR (melt mass flow rate) of 2 to 15 g / 10 min, and an ethylene-α-olefin. The density of the copolymer is 0.885 to 0.924 Kg / m ³ , the MFR is 2 to 15 g / 10 min, and the thickness of the film is 60 μm to 80 μm. Insulating paper container.   The heat-insulating paper container according to any one of claims 1 to 7, wherein the moisture content of the base paper is 7.2% to 8.8%.   It consists of a container body member and a bottom plate member. A thermoplastic synthetic resin film having a high melting point is laminated on the inner wall surface of the base material of the container body member and the bottom plate member, and a low melting point thermoplastic synthesis is performed on the outer wall surface of the base paper of the container body member. A method for producing a heat-insulating paper container, wherein a resin film is laminated and heat-treated so as to foam the low-melting thermoplastic synthetic resin film, wherein the low-melting thermoplastic synthetic resin film is made of low-density polyethylene and A method for producing a heat-insulating paper container, comprising a mixture of an ethylene-α-olefin copolymer.   The method for producing a heat insulating paper container according to claim 9, wherein a mixing ratio of the low density polyethylene and the copolymer of ethylene-α-olefin is in a range of 70:30 to 90:10.   The heat insulation according to claim 9 or 10, wherein a printed surface is formed on the surface of the low-melting thermoplastic synthetic resin film, and the low-melting thermoplastic synthetic resin film having the printed surface is heat-treated so as to foam. A method for producing a paper-made container.   The method for producing a heat-insulating paper container according to claim 11, wherein the printed surface includes a printed surface coated with white ink as a base and a printed surface coated on the upper surface thereof.   The heat-insulating paper according to claim 11 or 12, wherein the printed surface is coated with a synchronization ink that forms a smooth printed surface in synchronization with foaming on the surface of a low-melting thermoplastic synthetic resin film after foaming. A method for manufacturing a container.   The method for producing a heat-insulating paper container according to claim 9 or 10, wherein a printing surface is provided between the base paper and a low-melting-point thermoplastic synthetic resin film. The low-density polyethylene constituting the low-melting-point thermoplastic synthetic resin film has a density of 0.910 to 0.924 Kg / m ³ , an MFR (melt mass flow rate) of 2 to 15 g / 10 min, and an ethylene-α-olefin. The density of the copolymer is 0.885 to 0.924 Kg / m ³ , the MFR is 2 to 15 g / 10 min, and the thickness of the film is 60 μm to 80 μm. Manufacturing method for heat-insulating paper containers.   The method for producing a heat insulating paper container according to any one of claims 9 to 15, wherein the moisture content of the base paper is 7.2 to 8.8%.   The method for producing a heat insulating paper container according to any one of claims 9 to 16, wherein the heat treatment is heated at a high temperature of 115C to 130C for 3 minutes to 8 minutes. The method for producing a heat-insulating paper container according to claim 17, wherein the heat-insulating paper container is transferred and heated while being rotated on a conveyor.

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