JPS6382936A - Closed-end seamless molded vessel made of paper and manufacture thereof - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention (Industrial Applications! [17) The present invention relates to a bottomed seamless paper molded container and a method for manufacturing the same. This invention relates to a heat-resistant container that can heat and cook the contents.

(Prior art) Tray-shaped paper containers are widely used as containers that can be easily filled with food and other contents, but in recent years, with the spread of ovens, microwave ovens, toaster ovens, etc. In other words, it is desired to develop a container that can be filled with uncooked foods in a tray-like container to collect light, and that can be heated or cooked by placing the entire container in the aforementioned heater for single-serve water. .

As a response to such requests, the special public
No. 890 discloses that after preparing paper stock at near neutrality, a base paper is made by permeating an aqueous dispersion containing an inorganic filler, and then a heat-resistant coating is attached or laminated on both sides of the base paper. A method of manufacturing paper for food containers is described, which comprises applying a heat-resistant resin to the surface that will become the inside of the container. In addition to aluminum foil, resins such as nitrocellulose lacquer, epoxy, urethane, and fluorine are used as the heat-resistant coating. It is also described that #thermal resin such as silicone type is applied.

(Problem to be solved by the invention) This container is filled with raw materials such as Uiro, Castella, etc.
Although it can be used for applications that require heat treatment at temperatures of about 0 to 250°C, when heating or baking in a toaster oven, etc., the temperature of the container reaches a high temperature of 300°C or more, and such For high-temperature applications, the heat resistance has not yet been sufficiently satisfactory.

Paper cellulose fibers begin to carbonize and become colored at a temperature of about 260°C and are completely carbonized at a temperature of about 300°C.

Thus, when paper containers are used in applications where they are heated to temperatures of 300°C or higher, the appearance of the container itself becomes colored black to the extent that it cannot withstand use, and the strength of the container itself is also significantly lost. It is.

In order to hide the coloring of paper containers, it is natural to consider providing a coating layer consisting of a hiding pigment and a resin binder on the surface of the paper substrate, but such coated paper generally has a high elongation required for molding. The drawback is that there is difficulty in press forming into the tray.
In addition to this molding problem, when the press mold is heated to improve its moldability, the coating layer adheres to the mold, making molding impossible.In addition to this molding problem, conventional tray containers made of coated paper When heated in an oven, it tends to generate a bad odor and also has the disadvantage of impairing the flavor of foods.

Therefore, the present invention provides a heat-resistant paper laminate that is composed of a paper laminate with excellent formability and has excellent extrusion properties, container strength, and flavor retention even when the container wall is heated to a temperature of 300°C or higher. The purpose of the present invention is to provide a flexible paper container and a method for manufacturing the same.

(Means for Solving the Problems) The present inventors used a thermosetting resin as the resin when coating a paper substrate with a coating layer containing a resin and a hiding pigment. When applied in aqueous dispersion or water-soluble form, the seepage into the paper substrate that occurs when applying organic solution-based paints is prevented, and as a result the processability of paper laminates is significantly improved and the laminate It was also found that the body's heat resistance was significantly improved.

That is, the present invention provides a bottomed seamless molded container comprising a paper substrate and a resin coat layer provided on at least one surface of the paper substrate, wherein the resin coat layer contains a thermosetting resin and a hiding pigment. The resin coat layer has the same thickness as the laminate, and the paper 2! The present invention relates to a seamless molded container with a bottom, characterized in that the container is configured to satisfy g/L<0.1, where I is the depth of penetration into the interior of the container.

The present invention further includes a concealing pigment as a dispersoid and an average particle size of 0.0.
An aqueous dispersion containing 5 to 1.0 pm of thermosetting resin is applied to at least one surface of the paper substrate, the coated layer is dried, and the thermosetting resin is cured.

The present invention relates to a method for manufacturing a seamless molded paper container with a bottom, which comprises press-molding the obtained laminate into the shape of a seamless container with a bottom.

The present invention further provides paper 2! a water-based paint containing a hiding pigment as a dispersoid and a water-soluble thermosetting epoxy-acrylic resin as a resin component. The thermosetting resin is applied to at least one surface of the resin, the applied layer is dried, and the thermosetting resin is cured.
The present invention also relates to a method for producing a seamless molded paper container with a bottom, which comprises press-molding the obtained laminate into the shape of a seamless container with a bottom.

(Function) In FIG. 1 showing a perspective view of the heat-resistant paper container of the present invention,
This tray-shaped paper container includes a rectangular and flat bottom wall portion 1;
It consists of side walls 2a, 2b, 2c, and 2d that are connected to the bottom wall 1, and there are folds 3 between the adjacent side walls.
, and a flange portion or curl portion 4 is provided at the upper end edge of the side wall portion.

In FIG. 2, which shows an enlarged cross-sectional structure of the wall of this paper container, the wall 10 is made up of a paper substrate 11 and heat-resistant coating layers 12a and 12b applied to both surfaces of the paper substrate.

In the present invention, these heat-resistant coating layers 12a, 12b
is formed from a concealing face mask 4 and a thermosetting resin. First, the hiding pigment thermally isolates the paper substrate 11 from the heated high-temperature atmosphere, thereby maintaining the paper substrate's tendency to decrease in strength under heating to a small level, and also acts on the coating itself. The concealing pigment contained in the paint has the effect of imparting heat resistance and maintaining a good appearance by concealing the TA fiber carbonized substances generated on the paper substrate.Furthermore, the concealing pigment contained in the paint prevents the formation of resin stickiness on the surface of the mold. It also serves the auxiliary action of somewhat reducing build-up and improving moldability.

The hiding pigment is retained on the paper substrate surface via a resin binder, which must be a thermosetting resin. First, when using a thermoplastic resin as the coatings 12a, 12b, When press-molding into a container, this coating tends to cause molding problems such as sticking to the mold,
In addition, when heated in an oven, etc., bad smells, strange tastes, and strange odors are generated, which impairs the flavor of foods, and there is a marked tendency for the strength of the container itself to decrease. By doing so, the above-mentioned disadvantages can be eliminated or alleviated.

When forming the coating layers 12a and 12b, an aqueous dispersion containing a hiding pigment and a thermosetting resin with an average particle size of 0.05 to 1.0 lm is used as a dispersoid, or an aqueous dispersion containing a hiding pigment as a dispersoid is used. The second feature is that a water-based paint containing a water-soluble thermosetting epoxy-acrylic resin as a resin component is used. Traditionally, paints containing pigments and thermosetting resins are mostly used as solutions in organic solvents. However, as already pointed out, when an organic solution type paint is applied to a paper substrate, it is unavoidable that the thermosetting resin penetrates deeply into the paper substrate. By applying the pigment and thermosetting resin in the form of an aqueous dispersion, or by applying the thermosetting resin in water-soluble form, the degree of penetration of the thermosetting resin into the paper substrate can be significantly reduced. .

That is, the thickness of the vessel wall (laminate) 10 is L, the resin coating layer 1
When the penetration depth from the surface of 2a (12b) is 2,
According to the invention, I! , /L can be suppressed to less than 0.1, preferably within the range of 0.015 to 0.08.

However, the penetration depth l may differ between the maximum depth and the minimum depth depending on the condition of the paper quality, but in this case, the average penetration depth should be l.

The following are possible reasons why the penetration depth of L and the resin coat layers 12a and 12b can be suppressed to a small value by using a water-based dispersion type or water-soluble type resin. That is, the paper substrate in the present invention uses a neutral sizing agent such as an alkyl ketene dimer or alkenyl succinic anhydride, or a rosin-based sizing agent with a weakly acidic formulation that has a reduced amount of sulfuric acid bands. Sizing treatment is performed to make paper water resistant, that is, to prevent water from seeping into the paper even if the surface of the paper gets wet. Therefore,
When a water-based paint containing water as a medium is applied to a paper substrate as in the present invention, the degree of seepage of the resin into the paper substrate is significantly suppressed due to the effect of the sizing agent. Additionally, since paper generally absorbs water and organic solvents through the gaps between the fibers through mechanical action, if the resin is an aqueous dispersion larger than the gaps between the fibers, seepage of the resin into the paper base can be further suppressed. become.

On the other hand, when a solvent-based paint is used, the paint permeates deep into the paper substrate because the sizing agent does not have the effect of suppressing seepage of the organic solvent.

Moreover, in the present invention, the resin coat layer 12a.

The reason why the moldability of the laminate is improved and the thermal properties are also improved by suppressing the penetration depth of 12b to a small value is considered to be as follows. In other words, it is recognized that the press formability of paper laminates is due to the paper fibers being moderately intertwined or crossing each other in the paper substrate, and maintaining a moderate elongation. If the curable resin permeates deeply into the interior, the intertwined or intersecting parts become fixed and the elongation of the paper substrate is lost, resulting in a loss of press formability. On the other hand, in the laminate according to the present invention, the penetration depth of the thermosetting resin is extremely shallow, and the original elongation of the paper substrate is maintained, and as a result, it is thought that good press formability is maintained. . In addition, the permeation of the thermosetting resin into the paper substrate is suppressed, and the formation of a dense heat-blocking film on the surface of the paper substrate increases the heat resistance of the laminate. It is recognized that this improves sexual performance.

(Operations and Effects of the Invention) According to the present invention, a coating layer containing a hiding pigment and a thermosetting resin is provided on the surface of a paper substrate while suppressing permeation into the paper substrate. Excellent formability is obtained,
It is possible to significantly improve the appearance characteristics, container strength, and flavor retention of the container even when the container wall is heated to a temperature of 300°C or higher, and can be used in both microwave ovens and toaster ovens. We were able to provide dual ovenable containers to get the job done.

(Detailed Description of the Invention) In the present invention, any thermosetting resin, phenol,
Formaldehyde resin, furan-formaldehyde resin, xylene-formaldehyde resin, ketone-formaldehyde resin, urea-formaldehyde resin, melamine-
Formaldehyde resins, alkyd resins, unsaturated polyester resins, epoxy resins, bismaleimide resins, triallyl cyanurate resins, thermosetting acrylic resins, silicone resins, and the like may be used alone or in combination of two or more.

Among these, in the present invention, a combination of an epoxy resin and a reactive acrylic resin and/or vinyl resin having a functional group such as a carboxyl group, a hydroxyl group, or an amino group, such as a group reactive with the epoxy resin, is preferred. It is. These epoxy/acrylic or epoxy/vinyl coatings are particularly suitable for the purposes of the present invention in that they have excellent processability under crosslinked conditions and less stickiness formation on mold surfaces. .

As the epoxy resin component, an aromatic epoxy resin obtained by condensing bisphenol A and shrimp halohydrin is particularly suitable, and its epoxy equivalent is generally 1.
For the acrylic resin, the monomer component providing the functional group may be an unsaturated carboxylic acid such as methacrylic acid, acrylic acid, or maleic anhydride, or an anhydride thereof; ( Doroxy group-containing monomers such as meth)acrylic acid-2-hydroxyethyl ester and (meth)acrylic acid-2-hydroxypropyl ester; (meth)acrylic acid-2-aminoethyl ester and (meth)acrylic acid = 2-N,N-diethylaminoethyl ester, (meth)acrylic acid-N-aminoethyl-aminoethyl ester, etc., at least one type of heptamine group-containing substance, and (meth)acrylic acid alkyl ester (for example, methyl methacrylate, Examples include copolymers containing at least one type of ethyl acrylate, etc.) and, if desired, styrene. In addition, as a vinyl resin,
Vinyl chloride-maleic anhydride copolymer, vinyl chloride-acrylic acid-acrylic acid ester copolymer, vinyl chloride-
Examples include vinyl resins containing carboxyl groups and/or hydroxyl groups, such as partially saponified vinyl acetate copolymers, vinyl chloride-styrene maleic anhydride copolymers, and saponified vinyl chloride-methacrylic acid-vinyl acetate copolymers.

These resins may be in the form of an aqueous dispersion in which resin particles have a diameter of 0.05 to 1.0 mm, particularly in the form of an aqueous emulsion emulsified with a surfactant or self-emulsified. It is used in water-soluble forms as well as in combinations thereof.

Among these, for the purpose of the present invention, it is preferable to use epoxy-acrylic resins, particularly self-emulsifying epoxy-acrylic resins. Suitable examples of such epoxy-acrylic resins include acrylic acid or methacrylic acid 1.
2 to 3 Oi amount%, and styrene, methylstyrene,
A number-average molecule containing 70 to 88% by weight of one or more of vinyltoluene or an alkyl ester having 1 to 8 carbon atoms of acrylic acid or methacrylic acid, neutralized with an alkali of 310,000 to 100,000. type acrylic resin (A), and an average of 1 per molecule
．． Epoxy resin with an excess of carboxyl groups and acrylic having residual oxirane rings reacted with an aromatic epoxy resin (B) having a number average molecular weight of 1,400 or more and having 1 to 2.0 epoxy groups; acrylic; v8 resin partial reaction Dispersed in an aqueous medium in the presence of an amount of ammonia or amine such that the pH of the final coating composition is between 5 and 11.

Also, the ratio of acrylic resin and epoxy resin may be set to 8, for example.
Increase the ratio of acrylic resin such as 2:2 or 9:1,
Examples include those made water-soluble by adding a small amount of alcoholic solvent.

Furthermore, a combination of a water-soluble resin and an aqueous emulsion resin can also be used.

Hiding Pigments Hiding pigments include non-toxic or low toxicity pigments with a high hiding power, especially those with a hiding power (JISK 5101) of 40.
The following pigments are used: Examples of suitable pigments are:

These pigments may be used alone or in combination of two or more types, but the preferred pigment is one mainly composed of rutile type or anatase type titanium white (titanium dioxide). Of course, instead of using titanium white alone, for example, a small amount of yellow iron oxide, red iron oxide, or ultramarine may be blended to create a colored coating layer of cream color, pale pink, pale blue, etc. On the other hand, aluminum hydroxide, magnesium hydroxide, talc, clay,
Fillers or extenders such as magnesium silicate and calcium silicate may be used in combination.

Paper 71 (quality paper includes natural pulp such as softwood pulp and hardwood pulp, inorganic fibers such as glass fiber, rock wool, slag wool, asbestos, and ceramic fiber; polyolefin,
Examples include natural or synthetic paper obtained by paper-making one or more synthetic resin pulps such as polyester, polyamide, and polyimide. These papers can be blended with a fuel-resistant filler 1, such as aluminum hydroxide, magnesium hydroxide, calcium aluminate, dawsonite, and the like. In addition, silica, talc, clay, calcium carbonate, etc. can be added to improve the texture, stiffness, etc. of 1 paper, which further improves papermaking properties and improves 1i! In order to bond or fix AM to each other, an organic resin binder can be used. In the present invention, even when ordinary paper obtained from wood pulp is used,
wJ has an advantage of having excellent heat resistance.0
The basis weight of the paper substrate is between 100 and 600 g/m2, especially 15
It is desirable that it be within the range of 0 to 400 germ2.

In terms of heat resistance, slightly acidic paper or neutral paper, particularly neutral paper using an alkyl ketene dimer, alkenyl succinic anhydride, etc. as a sizing agent, is particularly preferred.

Manufacture of laminated material The laminated material used in the present invention is produced by preparing an aqueous coating solution containing the above-mentioned thermosetting resin and concealing pigment, and applying this coating solution to both sides of paper and S material. Obtained by curing.

Although the ratio of the thermosetting resin and the hiding pigment can be varied, the resin of the coating layer has the following formula % formula % (1) In the formula, ○^ is the oil absorbing material of the hiding pigment (If/1oog) L, dR represents the density of the resin (g/mf), k is a number from 0.005 to 0.2, and ff satisfies the following.
It is preferable to exist at a ratio of 1ffi (Rp).

In the specification, the formula (1) has the following meaning.

OA on the right side of equation (1) is the oil absorption amount of the hiding pigment (ml
/ 100 g) L, and the product of this and the density dR of the resin is the amount of binder per 100 g of pigment, to the extent that a homogeneous composition can be formed in which the resin is a continuous phase and the pigment is a dispersed phase. It means the number of grams. Therefore, when this composition is applied to a smooth, impermeable substrate surface such as a glass plate, the formula (
When the value of k on the right side of 1) is 0.01 or more, the pigment particles are not exposed on the outer surface, and a coating layer is formed inside without voids or irregularities near the surface. In this case, the pigment particles are exposed on the outer surface, or a coating layer with voids or unevenness is formed inside the pigment particles near the surface.

At a pigment-to-resin weight ratio (Rp) where the value of k in formula (1) is 0.2 or less, the pigment particles are exposed on the outer surface, or a coating layer with voids or unevenness is formed inside the pigment particles near the surface. ,
A laminate having such a coating layer has the same elongation as the paper substrate and can be easily formed into a tray shape. In terms of pigment adhesion, there is a certain minimum standard value of L, and the value of k is 0.0.
If the value falls below 05, the hiding pigment may come off during molding, and the #thermal strength of the vessel wall also decreases.

The solid content concentration of the coating liquid is as low as possible within the range that allows uniform coating, and is generally 20 to 80 L.
The range of weight 6 is suitable.

For the coating 71, coating means such as spray coating, electrostatic coating, roller coating, gravure roll coating, dip coating, and electrodeposition coating are used.

The coating amount on the paper substrate is 2 to 30112/2 as solid content.
By setting L to 5 to 20 m2/g, a satisfactory combination of heat resistance and workability can be obtained.

Curing of the coating formed takes place by means known per se, such as catalysis, heating or irradiation with ultraviolet light or radiation.

Forming into containers Forming into bottomed seamless containers such as trays, bowls, and cups is performed by heating a male mold and a female mold, supplying a laminated material between them, and press-molding. By heating the mold, the molding of the laminated material is dramatically improved compared to when an unheated mold is used. The heating temperature of the mold is
In general, it is desirable that the temperature be in the range of 50 to 180°C, particularly 90 to 150°C.

The invention is illustrated by the following example.

Example 1 First, a water-based epoxy-acrylic paint containing titanium white as a hiding pigment was prepared by the following procedure.

(A) Production of carboxyl group-containing acrylic resin Styrene 300.0 parts Ethyl acrylate 210.0 methacrylic m
90.0 Benzoyl peroxide 1
2.0 A storm of the mixture with the above composition was placed in a 4-tube flask purged with nitrogen gas, heated to 80 to 90°C, kept at that temperature, and gradually added the remaining 38 drops over a period of 2 hours. After the addition was complete, After further stirring at that temperature for 2 hours, it was cooled, and the resulting mixture had an acid value of 93 (in terms of solid content, the same applies hereinafter), a solid content of 59.7%, and a viscosity of 4100 cps (25°C, all viscosities below are 25°C).
A carboxyl group-containing resin solution was obtained.

(B) Manufacture of epoxy resin solution 500 parts of Epicote 1007 was charged into a 4-tube flask purged with nitrogen gas, gradually heated to raise the internal temperature to 100°C, stirred for 1 hour to completely dissolve, and then cooled to 80°C. An epoxy resin solution having a solid content of 60% was obtained.

(C) Preparation of aqueous coating resin composition 100.0 parts of the above (A) carboxyl group-containing acrylic resin solution (B) above
Epoxy resin solution 50.0■ 2-dimethylaminoethanol 9.3■ Ion exchange water
290.74 Charge the entire amount of ■ into a Tulo flask, add ■ without stirring, and neutralize the contained carboxyl groups approximately equimolarly, then raise the internal temperature to 80°C, and at this temperature After stirring for a minute, the mixture was cooled to room temperature. The reduction rate of oxirane % was 63.5% L, and the viscosity was also 1.5 times thicker after packing compared to before packing.

The thus obtained dispersion has an oil absorption of 20, which is equivalent to the solid content.
By adding rutile titanium oxide with a specific gravity of 4.2 and ion-exchanged water, the total solid content of resin and titanium oxide is 50%.
This mixture was kneaded using a ball mill type attritor to uniformly disperse titanium oxide.

Next, this titanium white-containing water-based epoxy-acrylic paint was stretched by 2.0% in length and 6.0% in width.1 basis weight: 300 g/
Softwood pulp (NBKP) as chemical pulp with RA2
30wt%, hardwood pulp (LBKP) 70wt%
It was coated with a bar coater on both sides of an acid-free paper substrate containing 5 wt% of talc as an inorganic filler and alkyl ketene diamond as a sizing agent.
A dry bake was carried out in the oven for a minute. The amount of paint applied is 14g/m2 on one side, and the amount of concealing pigment applied is 7g/m2.
It was 2.

Figure 3 shows a photograph of the cross-section of the thus obtained laminate taken magnified using an optical microscope. When L and l were measured from this figure, L was 380 μm, and 73 was the maximum value. 21.7 ALm at minimum value, 8.9 ALm at minimum value,
The average value of ``f' was 10.3 gm. Therefore, the value of 24/L is 0.057 at maximum i1N, and 0.057 at minimum iffo, 018
, the average value was 0.027.

Next, using the laminate coated with this titanium white-containing epoxy-acrylic paint on both sides, blanking and scoring are performed, followed by temperature control and press molding using a press mold maintained at 140°C. L, vertical 16CI11. as shown in FIG. Width 8.5cm, depth 2cm
A square tray was obtained.

In this case, the paint adhered to the mold during molding and did not fall off, and the molding was performed satisfactorily without any cracks or cracks.

Six chicken nuggets were placed in this square tray, stored in a freezer for 20 minutes, and then heated in a toaster oven for 8 minutes. After heating, I took the tray out of the toaster oven and tried the chicken nuggets, which were at the right temperature and delicious. Further, at this time, the surface of the square tray was not burnt and no discoloration was observed.

Examples 2-5. Comparative Examples 1 and 2 The paint shown in Table 1 was applied to both sides of the paper substrate used in Example 1 using a bar coater so that the coating amount was 14 g/m2 solids per side, and the mixture was baked in an oven at 190'C for 1 minute. It was dried and cured inside.

Figures 4 to 9 depict photographs of the cross-sections of the various laminates obtained in this way, taken enlarged using an optical microscope.
From this figure, L and i are determined as 3+11, and f/
The calculated values of L are shown in Table 1.

Next, each laminate was blanked and ruled, and then molded with a press mold maintained at 140°C to form a size of 16 cm in length, 9.5 cm in width, and 2.5 cm in depth as shown in Figure 1.
It was molded into a 0 cm square tray. Table 1 shows the press formability in this case, that is, the degree of paint sticking to the mold, paint falling off, paint cracking, and laminate breakage. As is clear from Table 1, when organic solvent-based paint is used, A
When the value of /L was large, it was observed that there was a tendency for breakage or cracks to occur during molding.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a heat-resistant paper container of the present invention, and FIG. 2 is a cross-sectional structural view of the wall of the paper container of the present invention.
, FIG. 3 is a microscopic photograph showing the cross-sectional structure of the laminate of Example 1, and FIGS. 4, 5, 6, and 7 are the laminates of Examples 2 to 5, respectively. FIGS. 8 and 9 are micrographs showing the cross-sectional structures of the laminates of Comparative Examples 1 and 2. FIGS. Reference number 1 is the bottom wall, 2a, 2b, 2c, and 2d are the side walls, 3 is the fold, 4 is the flange or curl, 10 is the wall, 11 is the paper substrate, and 12a. 12b indicates #thermal coating layer. Figure 1 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9

Claims (7)

[Claims] (1) A bottomed seamless molded container consisting of a paper substrate and a resin coat layer provided on at least one surface of the paper substrate, in which the resin coat layer contains a thermosetting resin and a hiding pigment; For the resin coat layer, where L is the thickness of the laminate and l is the penetration depth from the surface of the coat layer into the paper substrate, l/L<
1. A seamless molded container with a bottom, characterized in that the container is provided so as to satisfy 0.1. (2) The molded container according to claim 1, wherein the paper substrate is low acid paper or neutral paper. (3) The molded container according to claim 1, wherein the thermosetting resin is a curable composition containing an epoxy resin component and a curing agent resin component that is reactive with the epoxy resin. (4) The molded container according to claim 1, wherein the hiding pigment is titanium dioxide. (5) Hiding pigment as dispersoid and average particle size 0.05 to 1
．． An aqueous dispersion containing a 0 μm thermosetting resin is applied to at least one surface of the paper substrate, the applied layer is dried, the thermosetting resin is cured, and the resulting laminate is shaped into a seamless container with a bottom. A method for producing a bottomed, seamlessly molded paper container, which is characterized by press molding. (6) The method according to claim 5, wherein the aqueous dispersion of thermosetting resin is a curable epoxy-acrylic resin having self-emulsifying properties. (7) A water-based paint containing a hiding pigment as a dispersoid and a water-soluble thermosetting epoxy-acrylic resin as a resin component is applied to at least one surface of the paper substrate, the coated layer is dried, and then heated 1. A method for producing a seamless molded paper container with a bottom, which comprises curing a curable resin and press-molding the resulting laminate into the shape of a seamless container with a bottom.