JP2003321020A - Paper for heat insulating container and paper cup using the paper for its body - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a paper container which has heat-insulating properties, maintains container strength, is easy to form a cup, is easy to disposable and is less in environmental load and to provide paper for the paper container. <P>SOLUTION: The paper for the heat-insulating container has a first projection in at least part of the surface thereof which corresponds to the external surface of the container. Further, the first projection has a second projection. The paper is used for the body of the container. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat insulating container used for a paper cup for instant noodles, a paper cup for hot beverages, and the like, and a paper used therefor.

[0002]

2. Description of the Related Art Containers for food, such as cup noodles, tea, coffee, soup, stew, miso soup, etc., which can be drunk mainly by pouring boiling water, or containers used for hot beverages at fast food stores, etc. The expanded polystyrene container has excellent heat insulation and heat retention, and has good molding and processability.
It is also popular because it is cheaper. However, with the recent increasing interest in resource conservation and environmental issues, paper that can be crushed into small pieces when it is discarded as household waste, is easy to incinerate, and can be biodegraded by microorganisms in the soil is used. There is an increasing demand for food containers that are the main constituents.

As a container of this type, which is mainly composed of a paper base material, one in which a thermoplastic resin such as polyethylene is laminated on at least one surface of the paper base material is used.
There is a problem that heat insulation is low and heat is transferred directly to the hand holding the container and it is hard to hold, or that the container softens and the strength of the container decreases. In the present specification, the fact that it is hard to feel the heat in the hands and fingers when holding the container is referred to as "practical heat insulation".

[0004] As a means for improving "perceived heat insulation",
A method of providing an insulating air layer between the cup body and the outer wall has been proposed. For example, Japanese Patent Application Laid-Open No. 4-201840 proposes a paper container in which a step is provided on the upper peripheral wall of the body portion and a paperboard is wound around the cup body portion from the outside to form a gap.

Further, Japanese Utility Model Laid-Open No. 4-45212 proposes a method of providing a heat insulating air layer on the bottom of a cup body by using an inwardly curled peripheral paper. Furthermore, JP-A-7
Japanese Patent No. 223683 proposes a method in which a band-shaped projection is provided on the circumference of the outer wall surface of the body of the cup body and a heat insulating air layer is provided between the band projection and the outer wall surface.

However, in any of the above-mentioned methods for providing the air insulating layer, there is a problem that these voids are crushed when the cup is held because the air insulating layer is provided by increasing the voids. Therefore, the basis weight of the base paper has to be increased to cope with it, but in that case, there is a problem that the purpose of resource saving cannot be achieved.

Therefore, a method of adhering a paper having an embossed pattern on the outer circumference of the cup has been proposed in Japanese Utility Model Publication No. 6-39717. Further, Japanese Utility Model Laid-Open No. 6-65211 describes a method of winding embossed paper on the outside of a cup. In any case, since the cup having a double structure is manufactured, the cup forming machine becomes complicated, and both the inner cup and the outer cup require a certain amount of strength and rigidity. Will be used a lot.

[0008]

DISCLOSURE OF THE INVENTION According to the present invention, not only has a sensible heat-insulating property, but also maintains the strength of the container, is simple in cup molding, and is easy to dispose of at the time of disposal and has little environmental load. An object of the present invention is to provide a paper container and a paper for a paper container characterized by the above.

[0009]

In order to solve the above problems, the present invention adopts the following configurations. That is, the first aspect of the present invention is that at least a part of the surface corresponding to the outer surface of the container has a first convex portion, and the first convex portion further has a second convex portion. It is a characteristic paper for heat insulation containers.

A second aspect of the present invention is the same as the first aspect of the present invention.
The second convex portion is a paper for a heat insulating container, which is characterized by countless fine irregularities.

A third aspect of the present invention is the same as the first aspect of the present invention.
The second convex portion is a paper for a heat insulating container, characterized in that it is one to several protrusions having a width smaller than that of the first convex portion.

A fourth aspect of the present invention is characterized in that, in the first to third aspects, the first convex portion and / or the second convex portion is formed by embossing. A fifth aspect of the present invention is characterized in that, in the first to third aspects, the first convex portion and / or the second convex portion is formed by molding a biodegradable resin.

A sixth aspect of the present invention is a paper cup comprising a bottom portion and a body portion, wherein the paper described in any one of the first to fifth inventions is used for the body portion.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The heat-insulating container referred to in the present invention does not use a heat-insulating member having a so-called heat-retaining effect, and the heat can be tolerated even when a high temperature liquid or food is contained therein. What you can hold the container by hand,
That is, it means a container having "sensible heat insulating property".

<Regarding the Paper Used for the Container> The paper used for the container of the present invention is not particularly limited, but from the relationship between cup moldability and strength, 100-500 g / m 2 of paper base paper About m ² can be used, and preferably 200 to 400 g / m ² .

The paper used for the container has natural pulp fibers as a main component, and as the natural pulp, wood fibers (chemical pulp, mechanical pulp), non-wood fibers, waste paper pulp, etc. may be used as required. Used arbitrarily. Among the wood fibers, examples of the chemical pulp include kraft pulp that uses caustic soda and sodium sulfide during wood chip cooking, and sulfite pulp that uses sulfurous acid and bisulfite. These pulps may be unbleached or bleached. As mechanical pulp, groundwood pulp (GP) obtained by grinding logs with a grinder, refiner groundwood pulp (RGP) obtained by grinding (refining) waste wood from a sawmill, and wood. Thermo-mechanical pulp (TMP) obtained by heating and refining chips
And so on.

These pulp fibers may be used alone or in combination with 2
It is possible to use more than one kind in combination. If necessary, biodegradable resin fibers can be mixed within the range that does not impair the effects of the present invention. Examples of biodegradable resins that can be used include aliphatic polyester, biodegradable cellulose acetate, polylactic acid, and polycaprolactone.

When the paper used in the present invention is made into paper, a filler, a paper-making chemical and the like may be added if necessary. As paper-making chemicals, sizing agents used in ordinary papermaking,
Examples include paper strength agents and yield improvers. Examples of the sizing agent include alkyl ketene dimer, styrene acrylic resin, rosin and the like. Paper strength agents and yield improvers include polyacrylamide resins, polyamide epichlorohydrin resins, polyethyleneimine and its derivatives, polyethylene oxide, polyamines, polyamides, polyamide polyamines and their derivatives, cationic and amphoteric starch, oxidized starch, carboxymethylated. Organic compounds such as starch, vegetable gum, polyvinyl alcohol, etc., and inorganic compounds such as sulfuric acid band, alumina sol, colloidal silica, bentonite, etc. are used in appropriate combination.

As the filler, talc, kaolin,
Calcined kaolin, clay, diatomaceous earth, heavy calcium carbonate, magnesium carbonate, aluminum hydroxide, titanium dioxide, magnesium sulfate, silica, aluminosilicate, bentonite and other mineral fillers, polystyrene particles, urea formalin resin particles, etc. Fillers and the like can be appropriately selected and used in combination. Further, a papermaking additive such as a dye, a pH adjusting agent, a slime control agent, an antifoaming agent, and a sticky agent can be appropriately used depending on the application.

A slurry of raw materials and chemicals made of the above materials is made by a conventional method. The papermaking machine may be any of ordinary fourdrinier paper machine, cylinder paper machine, shortnet paper machine, inclined paper machine, various combination paper machines, etc., and is not particularly limited. The drying may be any of the conventional multi-cylinder dryer, Yankee dryer, through dryer, etc., and is not particularly limited. Further, in the present invention, the paper support obtained from the paper making step may be not only a single layer but also a laminated paper having two or more layers.

The ordinary paper as described above may be used, but in terms of the relationship with the embossing described later, low density paper is preferable because it can be formed following the shape of the embossing die. As the low-density paper, a paper sheet containing a curd fiber, a paper sheet in which expandable particles are foamed, mechanical pulp and / or pulp freeness is 550 to 800 ml · C.
An example is a paper sheet containing SF bleached kraft pulp. In addition, even if only ordinary bleached kraft pulp is used, it is relatively low in density due to the use of a large amount of surfactants such as bulking agents and neutral sizing agents such as alkyl ketene dimers, and it is easy to emboss paper. Is obtained. The density of paper is preferably about 0.5 to 0.8 g / cm ³ .

It is also possible to apply starch, polyvinyl alcohol, various surface sizing agents, pigments, etc. to the surface of the sheet by a coating method such as a size press or a gate roll.

The paper used in the present invention may be a laminate of two sheets of paper. Especially the total weight of paper is 200-500g / m ²
If it is, the weight of the paper (12) inside the container is 120-32
0 g / m ^2, can be the basis weight of the outer sheet (11) in the range of 80~180g / m ^2, preferably in that no wrinkling occurs during the cup mold. The bonding may be performed with a water-based or solvent-based adhesive, or may be extrusion lamination. However, in order to improve the moisture-proof property and because the embossing process described later is easy, it is preferable to bond the hot-melt adhesive. In this case, both sheets may be low density paper, the paper on the outer surface side of the container may be low density paper, or the paper on the inner surface side of the container may be low density paper. As will be described later, when only the paper on the outside of the container is embossed, the density of the paper on the outside is preferably 0.5 to 0.8 g / cm ³ . In any case, it is preferable that the density of the entire paper is about 0.5 to 0.8 g / cm ³ from the viewpoint of embossability and heat insulation.

<Regarding Lamination> In order to allow food containing a large amount of water to be placed in the molded container, it is necessary to provide a synthetic resin layer on the surface corresponding to the inner surface of the container. As the synthetic resin, wax, polyethylene, polypropylene, polyamide, polyester or the like can be used, and a method of extruding and laminating these resins on the paper surface is preferable.

<Regarding Biodegradable Resin of Inner Surface Resin Layer> As described in the problem to be solved by the present invention,
In consideration of environmental compatibility, the resin forming the inner surface resin layer is preferably a biodegradable resin. As the biodegradable resin used for the inner surface resin layer, polycaprolactone resin, biodegradable cellulose ester resin, polyalkylalkanoate resin, polylactic acid resin, aliphatic polyester resin, starch resin, polyvinyl alcohol resin And so on. In addition, 3-hydroxybutyric acid, 4-
Examples thereof include polymers or copolymers of hydroxybutyric acid, 3-hydroxyvaleric acid, and the like.

The above-mentioned inner surface resin layer is required to have heat sealability in addition to water resistance. The body heat seal in cup molding is generally 250 ° C. to 300 ° C. in the seal part.
It is carried out by a method of blowing hot air of ℃ to melt the resin to be heat-sealed and immediately pressing. Therefore, the melting point or flow starting temperature of the inner surface resin is preferably 250 ° C. or lower. In addition, the sealing strength after sealing is 100 ° C as well as bonding at room temperature.
It is necessary to maintain sufficient strength even when hot water is added. Therefore, the melting point or flow starting temperature of the biodegradable resin used for the inner surface resin layer is preferably 120 ° C. or higher.
The melting point or the flow starting temperature is 140 to 250 ° C, more preferably 140 to 230 ° C. The thickness of the inner surface resin layer is 1 in view of the necessity of liquid leakage prevention and heat seal strength.
It is about 0 to 100 μm, preferably about 15 to 50 μm.

The melting point referred to in the present invention means a differential scanning calorimeter (DSC-50 manufactured by Shimadzu Corporation or DS manufactured by Perkin Elmer Co., Ltd.).
It is the peak temperature in the case of showing a clear melting peak when measured at a heating rate of 10 ° C./min in the measurement by C-2 type). In addition, when there is no clear peak or when there is no melting point, the flow starting temperature is adopted instead of the melting point. Flow start temperature is flow tester (Shimadzu CL
T-500 type or CST-500 type), nozzle diameter 1 mm, nozzle length 10 mm, load 30 kg, preheating 6
The temperature is the temperature at which the polymer begins to flow out from the die when measured under the conditions of a temperature rise starting temperature of 50 ° C. and a heating rate of 3 ° C./min.

<Hot Melt Adhesive Layer> As described above, the paper of the present invention is preferably one obtained by laminating two sheets of paper with a hot melt adhesive, but because of the same environmental compatibility as above, The hot melt adhesive is also preferably biodegradable. The biodegradable resin composition used for the hot-melt adhesive layer is basically composed of a base polymer and a tackifier, as in the case of a normal hot-melt adhesive, and may have a viscosity such as wax when necessary. It contains a reducing agent. The base polymer is a polymer compound necessary for maintaining the strength as an adhesive and having an appropriate cohesive force. However, in order to enable hot melt coating, the base polymer itself also needs to be easily softened by heat, and also because the moisture-proof layer is not cracked by the molding process and the moisture-proof property is not lowered, A low softening point is required.

Examples of such a biodegradable base polymer include polylactic acid or a copolymer of lactic acid and hydroxycarboxylic acid described in JP-A-5-339557. In addition, natural rubber described in JP-A-7-278510 can be mentioned. Furthermore, JP-A-10
Aliphatic polyesters having a side chain described in JP-A-251612 can be mentioned.

As the aliphatic polyester having a side chain, an aliphatic dicarboxylic acid (anhydride or ester), an aliphatic dicarboxylic acid having an alkyl group or an alkenyl group (anhydride or ester), and an aliphatic glycol are reacted. Aliphatic polyesters may be mentioned. In the above, examples of the aliphatic dicarboxylic acid and the like include succinic acid or its anhydride or its diester, and as the aliphatic dicarboxylic acid having an alkyl group or an alkenyl group, alkylsuccinic acid or alkenylsuccinic acid, or their anhydrides. Or a diester. Examples of the aliphatic glycol include 1,2-ethylene glycol, 1,4-butanediol and 1,6-hexanediol. A specific example is a polyester having an average molecular weight of about 50,000 obtained by polycondensing 60 mol of succinic acid, 40 mol of octenylsuccinic acid and 1,4-butanediol.

The polylactic acid or the copolymer of lactic acid and hydroxycarboxylic acid is preferably a polymer having a molecular weight of 20,000 to 500,000. As the hydroxycarboxylic acid, glycolic acid, 3-hydroxybutyric acid, 4-hydroxybutyric acid, 4-hydroxyvaleric acid or the like can be used.

Natural rubber is present as rubber particles in a latex obtained from a rubber tree and has a rubber content of 30 to 40.
It is said that the weight% and the particle size are large and are 0.1 to 0.5 μm. The main component of the rubber particles in the latex is cis-1,4-polyisoprene, and the average degree of polymerization is about 5,000, but it is said that the surface of the rubber particles is covered with a phospholipid and protein layer. There is. The natural rubber used as the base polymer of the present invention is obtained by concentrating the latex to a rubber content of about 60% by weight and adding ammonia or the like as a preservative, or separating the rubber particles in the natural rubber latex by coagulating. It is possible to use dried, so-called raw rubber.

The tackifier will be described. The tackifier is also called a tackifier, and it is preferable to use it to enhance hot tackiness during hot melt coating,
At the same time, it also dissolves with the base polymer and acts to reduce the melt viscosity of the entire mixture. In the present invention, when used, it is necessary to use a biodegradable tackifier.
As an example, in the specification of Japanese Patent Application No. 2001-288295, the applicant has proposed rosin, terpene, rosin ester, shellac, polyalkylene alkanoate polyol, low molecular weight polycaprolactone diol proposed as a plasticizer for natural rubber biodegradable resin. , Low molecular weight polycaprolactone triol, etc. can be used. Anything else,
Terpene-phenol resin, low molecular weight polylactic acid, etc. can also be used.

The viscosity reducing agent may be added, if necessary, in order to improve the fluidity of the biodegradable resin composition during hot melt coating. As the viscosity reducing agent, a so-called wax can be used, but in the present invention, it is necessary that it is biodegradable, and various plant-based or mineral-based natural waxes can be used. For example, carnauba wax, castor wax, rice wax, paraffin wax, montan wax, microcrystalline wax and the like can be used. In addition, low molecular weight aliphatic polyester, fats and oils such as soybean oil, and low molecular weight polyether can be used.

<Formation of convex portion> The feature of the present invention is that by forming a two-step convex portion on the surface corresponding to the outer surface of the container, the area where the belly surface of the finger truly contacts the surface of the container is greatly reduced. And thereby exhibiting "sensible heat insulation". That is, even if the container itself does not have a high heat insulating property, the temperature actually felt by the finger is lowered by reducing the true contact area between the finger and the container (see FIG. 1).

The height of the first convex portion 1 (height difference from the lower portion) is preferably about 0.5 to 5 mm. Second
The height of the convex portion 2 (height difference from the lower portion) is 0.2 to 2
It is preferably about mm. The width of the convex portion 1 (the diameter of the convex portion when the convex portion is circular) is about 2 to 10 mm, preferably about 3 to 8 mm. The width of the convex portion 2 (the diameter of the convex portion when the convex portion is circular) varies depending on the number thereof and cannot be generally stated. For example, when one to several convex portions 2 are provided on one convex portion 1, the width thereof is about 1 to 5 mm, which is 1/5 to 1/2 of the width of the convex portion 1. preferable. FIG. 2 exemplifies a sectional pattern of the convex portion. 2 is an example in which the second convex portion 2 is provided by further subjecting the first convex portion 1 to the concavo-convex process. Is an example in which the second convex portion 2 is formed by subjecting the concave portion to the second convex portion 2 and an example in which the concave portion 3 is also subjected to the mountain-shaped concave portion.

The convex portion 1 and the convex portion 2 provided on the base paper are
Most typically, both can be formed by embossing. As a method other than embossing, corrugated cardboard-like corrugation is performed on the base paper microscopically,
Further, it may be crushed into a line shape in a direction orthogonal to the step. It can also be obtained by forming a synthetic resin layer on the surface of paper or during formation, and then cooling the molten resin by imprinting it with a cooling metal or the like (see FIG. 5).
This resin may be the same biodegradable resin as the resin used for the inner surface of the container. The convex portion 1 and the convex portion 2 may be formed at the same time, the convex portion 2 may be formed after the convex portion 1 is formed, or the convex portion 2 may be formed after the convex portion 2 is formed. 1 may be formed.

The embossing, which is the most typical embossing method, will be described in detail below. Embossing is
It can be carried out as shown in FIG. 3 by means of a mold making machine, a device called an embossing calendar or the like which is commonly used in the field of paper / paperboard. For example, a method is possible in which paper is passed while applying pressure between two rolls, at least one of which is an engraving roll. As a combination of rolls, two rolls are a combination of engraved steel rolls, one roll is an engraved roll and the other is an elastic roll, one is an engraved steel roll, the other is a flat steel roll, etc. There is. The embossing depth can be the deepest in the above combination, but since the cutting may occur depending on the weight of the base paper, the material and the density, it is necessary to select the embossing depth in consideration of the processing limit. In the case of paper containers, the above combinations are often used, and a continuous pattern engraved on a metal roll by a combination of a metal roll and a rubber roll is roll-pressed and then stamped on the base paper surface. If the paper thickness is thick or the density is low, the above method is also effective. In this case, the recesses are formed by compression and the remaining portions become the projections. FIG. 3 illustrates the molding methods 1 to 3 above.

The embossing process or the other concavo-convex process may be performed on the paper before it is made into a container, that is, the paper on which the operations such as printing, synthetic resin laminating, and pasting of the paper have been completed. Easy and good. However, when two sheets of paper are stuck together, the concavo-convex process may be performed on one sheet of paper (one outside the container) before sticking. The embossing on a thin paper has a narrower width and allows formation of deep irregularities. Hereinafter, the procedure in that case will be specifically described.

In this case, since the paper is thin, as shown in FIG. 4, at least the first convex portion 1 is shaped so that the entire paper 11 is extended and projected from the inner surface of the container by a convex engraving roll. Is good. The processing method is most preferably one of the embossing methods described above. Furthermore, in this case, it is possible to form two-step convex portions by one embossing process, which is preferable. When the paper 11 on the outside of the container in which the unevenness is formed is bonded to the other paper 12 with the hot melt adhesive, it is necessary to bond so that the formed unevenness is not crushed. As the method, when pressure is applied from the side corresponding to the outside of the container, a soft rubber or sponge-like sheet is wound around a roll to be pressed, pressed with a flexible bag having a fluid inside, and with air pressure. A method such as pressing paper is used.

[0041]

EXAMPLES Examples will be described below. Numerical values indicating the concentration, blending amount, coating amount, etc. are based on the solid component weight or the active ingredient weight.

Evaluation Test Method 1. <Experience thermal insulation test> After leaving the cup in an environment of 20 ° C and 65% RH for 24 hours, put warm water of 95 ° C in the cup and hold it for 3 minutes, then feel hot and change the finger position from the container. Is measured as the adiabatic time. The following five-stage evaluation is made within these time ranges. In order to reduce the measurement error by the tester, the average data is measured by three or more people. The touch was evaluated by evaluating the time during which the cup could be held by hand 3 minutes after pouring hot water. Rank 1: Over 60 seconds Rank 2: 45-60 seconds Rank 3: 30-45 seconds Rank 4: 15-30 seconds Rank 5: Less than 15 seconds

2. <Manufacture of container paper><Manufacture example 1 of laminated paper> Cup base paper (density 0.75 g / cm ³ ,
Natural rubber-based biodegradable resin 7 on the surface of tsubo 140g / m ² )
7% (mass%: same below), rosin-based tackifier (Haritac manufactured by Harima Kasei Co., Ltd.) 3%, microcrystalline wax 10%, natural paraffin wax 10% (viscosity of 5 Pa. S, flow starting temperature 110 ° C) was melted to 160 ° C, and a coating amount of 40 g / m ^{2 was} applied using a gear pump die coater [manufactured by Yuri Roll Machinery Co., Ltd.], and then another cup base paper (Density 0.75 g / cm ³ , rice tsubo 140 g / m ² ) is pressure-bonded to the resin layer and laminated to form a paper layer (11) / hot melt adhesive / paper layer (1
A processed base paper obtained by sequentially laminating 2) was obtained. On one surface of the processing sheet, further polylactic acid type resin (manufactured by Mitsui Chemicals, Inc. LACEA, mp 160 ° C.) 30 g / m ² melt extrusion lamination, the inner surface resin layer / paper layer (12) / hot melt A laminated processed paper in which the adhesive / paper layer (11) was sequentially laminated was obtained. The density of the laminated processed paper was 0.83 g / cm ³ .

<Example 1> From the surface corresponding to the inside of the container, the laminated processed paper was pressed with a "convex" engraving metal roll, and the opposite side was received with a rubber roll (Fig. 3). Part 2 was embossed. The temperature of the paper and convex roll was 80 ° C. The height of one peak of the convex portion 2 is 0.5
mm, the width was 1 mm, and the mountain was molded with almost no gap. Then, from the surface corresponding to the inside of the container, the convex engraved metal roll was pressed, and the opposite side was received by the corresponding engraved metal roll (FIG. 3) to apply pressure to emboss the convex portion 1. The temperature of the paper and convex roll was 80 ° C.
The height of one peak of the convex portion 1 is 2 mm, the width is 5 mm,
The mountain was molded with almost no gap. At this time, the engraved concave portion of the receiver was made deeper than the corresponding convex portion so that the tip of the convex portion 1 was not crushed.

A side blank of the container was punched out of this laminated processed paper, and a bottom blank was punched out of the laminated processed paper which was not embossed, and the paper layer (12) was placed inside by a molding machine manufactured by Herraf GmbH (Germany). The paper cup 10 as shown in FIG. Molding conditions are side seal part,
Both bottom seal parts have a heating temperature of 300 ° C (hot air outlet)
The surface temperature of the blank was about 200 ° C. There were no molding problems, and the cup could be molded. As a result of the above-described bodily sensation heat insulation test, the evaluation was 3.
The results are summarized in Table 1.

Example 2 Cup base paper (density 0.75 g /
cm ³ and 140 g / m ^{2 of} tsubo are embossed in the shape shown in FIG. The height of one peak of the convex portion 2 is 0.8
mm, the width is 1 mm, and the height of one peak of the convex portion 1 is 2
mm, the width was 4 mm, and the peaks of the convex portion 1 were molded with almost no gap. A laminated processed paper was manufactured in the same manner as in the laminated paper manufacturing example 1 except that this embossed paper was used as the paper (paper layer 11) on the outside of the container. However, at the time of hot-melt bonding, a sponge roll was used for pressure bonding so that the molded convex portion was not crushed. This laminated processed paper had the voids shown in FIG. 4 inside the convex portion 1. As a result of performing a bodily heat insulation test, the evaluation was 2.

<Comparative Example 1> Cup molding was carried out in the same manner as in Example 1 except that non-embossed paper was also used for the side blanks. As a result of the above-described bodily adiabatic test, the evaluation was 5. The results are summarized in Table 1.

Comparative Example 2 Cup molding was performed in the same manner as in Example 1 except that the convex portion 2 was not formed. The evaluation result was 4 as a result of the above-described bodily adiabatic test. The results are summarized in Table 1.

[0049]

[Table 1]

[0050]

INDUSTRIAL APPLICABILITY The cup of the present invention is a paper cup which not only has a bodily sensation of heat insulation, but also is easy to dispose of when discarded and has a low environmental load without impairing commercial properties such as printability and appearance.

[Brief description of drawings]

FIG. 1 is an explanatory view schematically showing the contact relationship between the abdominal surface of a finger and the two-step convex portion formed on the outer surface of the container when the heat insulating container of the present invention is grasped by hand.

FIGS. 2A to 2C are explanatory views showing a cross-sectional pattern of a concave-convex shape of a convex portion.

3A to 3D are explanatory diagrams showing a method of embossing calendering of a base paper.

FIG. 4 is an explanatory view schematically showing a cross section of a two-step convex portion on the outer surface of a heat insulating container formed by using laminated paper.

FIG. 5 is an explanatory view schematically showing a cross section of a two-step convex portion formed of a biodegradable resin on the surface of the raw paper forming the outside of the heat insulating container.

FIG. 6 is a perspective view showing a general example when a paper cup is held by a hand.

[Explanation of symbols]

1 First convex part 2 Second convex part 3 recess

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[Procedure amendment]

[Submission date] May 2, 2002 (2002.5.2)

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Correction target item name] All drawings

[Correction method] Change

[Correction content]

[Figure 1]

[Fig. 2]

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Claims (6)

[Claims] 1. A first convex portion is provided on at least a part of a surface corresponding to an outer surface of the container, and the first convex portion further includes a second convex portion.
A paper for a heat-insulating container, which has a convex portion. 2. The paper for a heat insulating container according to claim 1, wherein the second convex portion is an infinite number of minute irregularities formed. 3. The first convex portion is one to several protrusions having a width smaller than that of the first convex portion.
The paper for the heat-insulating container according to. 4. The paper for a heat insulating container according to claim 1, wherein the first convex portion and / or the second convex portion is formed by embossing. . 5. The first convex portion and / or the second convex portion is formed by molding a biodegradable resin, according to any one of claims 1 to 3. Paper for heat insulation containers. 6. A paper cup comprising a bottom part and a body part, wherein the paper according to any one of claims 1 to 5 is used for the body part.