JP2007016380A - Forming raw paper and paper formed container using the same or method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide forming raw paper which consists mainly of pulp, has high productivity and such good formability as not producing cracks in a substrate and unevenness in folded wrinkled portions, when press-formed, and is suitable for press-forming, to provide a deep-drawn paper container (deep-drawn container) applicable to a relatively deep tray or cup, especially a deep-drawn paper container having excellent flange smoothness, to provide a deep-drawn, lightweight paper container having high rigidity and not causing a container body and bottom-swelling phenomenon, and to provide a method for producing the same. <P>SOLUTION: This forming raw paper is characterized by having a high density layer having a density of 0.7 to 0.9 g/cm<SP>3</SP>and a low density layer having a density of 0.3 to 0.6 g/cm<SP>3</SP>, having a unit weight of 100 to 500 g/m<SP>2</SP>and a total density of 0.4 to 0.7 g/cm<SP>3</SP>, wherein the low density layer consists mainly of at least one kind of pulp selected from mechanical pulp, carded fibers, and mercerized pulp. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a molded base paper used as a material for a packaging container for packaging industrial products and the like. Further, the present invention relates to a molded paper that is a raw material of a container for storing fresh foods such as meat, vegetables and fresh fish, or various processed foods such as lunch boxes, prepared dishes, frozen foods, confectionery, and noodles. More specifically, the present invention relates to a forming base paper having a low environmental load at the time of disposal and having characteristics particularly suitable for press forming, and a method for manufacturing the same.

  Conventionally, plastic containers have been used in large quantities as food containers or packaging materials for various industrial products because they are easy to mold, can be mass-produced, and can be manufactured at low cost. As these plastic containers, for example, a polystyrene container obtained by molding a polystyrene foam bead or a polystyrene foam sheet by press molding, a polypropylene container, a polyethylene terephthalate container, a polyvinyl chloride container, etc. are widely used. However, the plastic container as described above has a problem that the burden on the environment at the time of disposal is high. In other words, when it is landfilled, it remains in the ground without being decomposed semi-permanently, and when it is incinerated, it has high calorie burns, so it easily damages the incinerator and is difficult to burn completely, especially using polyvinyl chloride. However, there are problems such as the possibility of generating highly corrosive hydrogen chloride gas.

  Therefore, in recent years, considering environmental problems, recycling problems, and resource saving, it can be recycled as an alternative to the above-mentioned plastic containers, has low combustion calories when discarded, has biodegradability, and is environmentally friendly. There is a need for containers made of low-load pulp. Conventionally, there is a pulp mold container as a molded body having a three-dimensional shape made of pulp or a material mainly composed of pulp. Pulp mold containers have been widely used as packaging containers for some time. The pulp mold container manufacturing method is to produce a net shape having an irregular shape corresponding to the intended container shape, and by sucking and making pulp slurry into the net shape and drying, the pulp raw material is formed into a desired shape It is a method to do. Therefore, the container shape obtained by this method has a certain degree of freedom. However, it took a long time to produce the pulp mold and there was a problem in productivity. In addition, it is difficult to impart sufficient water resistance and oil resistance, which is often required for a tray container for food, to the pulp mold container, resulting in an increase in cost.

As a method for obtaining a molded product mainly composed of pulp other than pulp mold, a method is known in which a base sheet mainly composed of pulp such as paperboard is press-molded under heating. This method is a method in which a base sheet with a ruled line is placed between a male and female mold and press-molded with hot pressure. Such a press molding method has a very high productivity because a molded body can be obtained by a single press.
However, unlike resins and metals, a base sheet mainly composed of paper pulp is generally poor in stretchability, spreadability, and stretchability. Therefore, if deep press molding is performed in order to mold a tray having a certain depth, the base sheet may not withstand the stretching and may break. Therefore, when ordinary paperboard or the like is used as a base material, only a molded container having almost no depth called a so-called paper dish can be manufactured, and the shape of the molded product obtained is very limited. Even if no breakage occurs, it is difficult to make a step at the crease part of the ruled line part or to smooth the container surface. In addition, when there is a step at the container edge of the tray, there is a gap for the step when a lid is attached or when sealing with a film or the like. It was. Furthermore, the breaking point starting from the paper fold is also the cause of lowering the strength of the tray.

In order to solve such a problem, for example, in Japanese Patent Laid-Open No. 5-286603, a method of heating and squeezing corrugated paper in which a plurality of corrugated bent portions are provided on a paper material to impart stretchability is disclosed in Japanese Patent Laid-Open No. -134898 is a method of press forming while heating a paper material that has been provided with stretchability by forming irregularities over the entire surface. In JP-A-7-214705, a humidified base paper is bonded. A method is disclosed in which a plurality of layers are stacked through an agent, and then corrugated and then press-molded.
However, all of these methods are such that the base sheet is previously wrinkled into a wave shape or the like to impart stretchability and press working after imparting press workability. Therefore, not only a wrinkling step is required before pressing, but wrinkles are present in the entire container after pressing, which not only detracts from aesthetics but is also not sufficient in strength.
Japanese Patent Application Laid-Open No. 7-315358 discloses a method of press forming a corrugated cardboard sheet while heating it with a metal mold. This method uses a corrugated cardboard sheet as a base material, and the flute structure causes distortion due to press working. Somewhat absorbed.
However, this method must use a corrugated cardboard sheet as a base sheet, and cannot be applied to a base material such as general paperboard. Moreover, it did not fully absorb the wrinkle irregularities generated by press working. In JP-A-6-239334, a method of press-molding a sheet in which pulp fibers contain an olefinic resin and impart stretchability is disclosed, and in JP-A-10-8393, thermoplastic resin fibers and pulp fibers are mixed. A method of hot press molding a sheet with improved stretchability is disclosed. However, these methods impart pressability to the base sheet by adding a thermoplastic resin to the base sheet mainly composed of paper. It damages the characteristics such as low environmental impact.

  In addition, the base sheet obtained by the above method has a large unevenness of the folded wrinkle portion generated on the curved surface when the molded product obtained by press-pressing them has a large curved surface portion. The surface was not smooth and the moldability was not good.

  In addition, the contents are higher than the tray shape for use in more diverse applications such as those containing a lot of water, or when putting liquids such as beverages, soups, cup noodle containers, etc. Plastic molded containers and cup molded containers having a certain side wall are used.

Japanese Patent Laid-Open No. 5-286003 JP-A-6-134898 JP 7-214705 A JP 7-315358 A JP-A-6-239334 Japanese Patent Laid-Open No. 10-8393

  An object of the present invention is a molding process mainly composed of pulp, which is suitable for press molding having good moldability and high productivity, in which cracks and unevenness of a folded wrinkle portion do not occur during press molding. It is to provide a base paper. An object of the present invention is to provide a paper drawing container (deep drawing container) that can be applied to uses such as relatively deep trays and cups. In particular, the present invention provides a paper drawn container having excellent flange smoothness. Furthermore, the present invention provides a highly rigid paper container that is deep-drawn, lightweight, and does not cause a container swelling or bottom swelling phenomenon, and a method for manufacturing the same.

The present invention has the following configuration in order to solve the above problems.
That is, the first invention, the high density layer of density 0.7~0.9g / cm ^3, and has a low density layer of the Density 0.3-0.6 g / cm ^3, a basis weight is 100 500 g / m ² , the overall density is 0.4 to 0.7 g / cm ³ , and the low density layer is mainly composed of pulp selected from at least one of mechanical pulp, curled fiber, and mercerized pulp. This is a processed paper.

  A second aspect of the present invention is the molded base paper according to the first aspect of the present invention, wherein the low density layer is mainly composed of mechanical pulp.

  A third aspect of the present invention is a forming base paper according to any one of the first and second aspects of the present invention, in which a paper sheet having a breaking elongation (JIS-P8113) of 5% or more is laminated on at least one side.

  A fourth aspect of the present invention is a paper molded container using the molded base paper according to any one of the first to third aspects of the present invention.

  A fifth aspect of the present invention is the paper molded container according to the fourth aspect of the present invention, which is formed by drawing.

A sixth aspect of the present invention is a method in which the forming base paper according to any one of the first to third aspects of the present invention is drawn using a pressing die at a temperature of 100 to 150 ° C. and a pressing pressure of 10 to 100 kgf / cm ^2. It is a manufacturing method of the paper-made container manufactured by shape | molding.

According to the present invention, there is provided a base paper having pulp as a main component, which is suitable for press molding having good formability and high productivity, in which cracks and unevenness of a folded wrinkle portion do not occur during press molding. It becomes possible to provide.
Furthermore, according to the present invention, it is possible to provide a paper-drawn container (deep-drawn container) that can be applied to uses such as relatively deep trays and cups.
In particular, it is possible to provide a paper draw-molded container having excellent flange smoothness. In addition, according to the present invention, it is possible to provide a highly rigid paper container that is deep-drawn, lightweight, and does not cause a container swelling or bottom swelling phenomenon.

Molding base paper of the present invention, a density of 0.3-0.6 g / cm ³ low-density layer, 2 or more layers made paper containing a dense layer of density 0.7~0.9g / cm ³ at And the overall density is 0.4 to 0.7 g / cm ³ .

  The forming base paper of the present invention may be a multi-layer paper having one low-density layer and one high-density layer. More preferably, both the outer layers on the front and back sides are high-density layers, and the middle layer that is a low-density layer is The sandwiched structure is more effective in obtaining a bulky and stiff base paper.

Paper, stiffness S of sheet paperboard or the like, when the sheet was considered cantilever, S = E · I / B · W = E · T 3/12 · W, (E: Young's modulus MPa, I: Cross section secondary moment N · cm ² , B: sample width mm, W: sample weight kg, T: sample thickness mm). That is, it can be considered that the stiffness S is proportional to the cube of the Young's modulus and the sheet thickness.

Furthermore, according to ATLuey of Tappi Nov.1963, Vol.46, No.11, the stiffness of a multi-layered sheet such as paperboard is similarly determined from the Young's modulus of each layer and the moment of inertia of each layer according to the above formula. The stiffness value of the entire sheet is obtained from the sum of the stiffness values of the respective layers.
Based on this concept, the distance from the center of the paper thickness is far, that is, the thicker the paper thickness, the higher the rigidity, so the middle layer may be bulky. Further, since the stiffness is indicated by the product of the cube of the thickness and the Young's modulus, the higher the Young's modulus is, the more effective the stiffness is.

From this, the density of the middle layer is 0.3 to 0.6 g / cm ³ . Severe decrease in interlaminar strength when the density of the middle layer to less than 0.3 g / cm ^3, also exceeds 0.6 g / cm ^3, that the density of the whole base paper and 0.4 to 0.7 g / cm ³ I can't.
In the present invention, the density of the outer layer needs to be 0.7 to 0.9 g / cm ³ . If it is less than 0.7 g / cm ³ , the Young's modulus of the outer layer decreases, and the rigidity of the present invention cannot be expected to improve. Further, when the density exceeds 0.9 g / cm ³ , the outer layer surface of the base paper becomes too tight, so that it is practically difficult to obtain a higher density layer at the paper making stage. Moldability is not accompanied.

The basis weight of molding base paper of the present invention is in the range of 100 to 500 g / ^{m 2,} more preferably in the range of 200 to 400 g / ^{m 2.} If the basis weight is lower than 100 g / m ^{2, the} molded product obtained after press molding does not exhibit sufficient strength, and if it exceeds 500 g / m ² , the moldability of the folded wrinkle portion is undesirably lowered.

There are no particular restrictions on the type of pulp used in the high-density layer, but it is particularly desirable to increase the beating degree of N-material (coniferous) pulp such as NUKP and NBKP so as not to lose rigidity.
In addition, in order to make this invention effective, it is preferable that the basic weight of the outer layer made into the high-density layer is 15-100 g / m < ² >. That is, if it is less than 15 g / m ² , it is difficult to obtain a layer having a high Young's modulus, and paper making itself is difficult. On the other hand, when the outer layer exceeds 100 g / m ² , the basis weight of the low density layer is relatively reduced, so that the density of the whole base paper is increased, and it is difficult to make the range from 0.4 to 0.7 g / cm ^3. Because.

  In the present invention, the pulp used as the low density layer is preferably a pulp having a freeness in the range of 200 to 650 ml in the re-disaggregation state according to the Canadian standard form of JIS-P8121. If the freeness is less than 200 ml, the pulp fibers are poorly drained, so that the squeezed sheet tends to have a dense structure, making it difficult to obtain a low-density paper layer structure. On the other hand, if the freeness exceeds 650 ml, the sheet becomes too low in density, and delamination occurs during the pressing process during paper making, and balloon-like swelling tends to occur. In addition, the stock which shows 200-650 ml freeness in a re-disaggregation state can be 250-700 ml by Canadian standard type freeness irrespective of the pulp raw material used. Further, measuring the freeness of the used pulp by re-disaggregating the base paper is effective for grasping necessary pulp characteristics from a product exhibiting good operability in a single hour.

The pulp raw material used for the low-density layer is mainly a pulp raw material from which a low-density paper layer can be easily obtained. Specifically, mechanical pulp is mentioned as such a pulp.
Mechanical pulp is usually pulp produced by pulverizing wood, especially N material, and then disaggregating it. There are GP, TMP, RGP and the like, and TMP and RGP are more preferable. Of these, materials made from radiata pine, southern pine, Douglas fir, etc. have the characteristic that the fibers are rigid and difficult to deform, so that a low-density paper layer can be obtained, and density reduction during press molding is also possible. It is particularly preferable because it is small. However, it is also possible to use various non-wood raw materials such as kenaf, straw, bamboo, and sugarcane sugarcane bagasse. In addition, pulp that has been partially chemically treated, such as pulp obtained by adding chemicals during mechanical crushing or pulp that has undergone a bleaching step, is also handled as mechanical pulp. Furthermore, the thing which gave the density reduction characteristic of the pulp by chemical processing, such as mercerized pulp and a curled fiber, can also be used conveniently.

In the present invention, the above-mentioned pulp is mainly used for constituting the low-density layer, but in addition, various kinds of chemical pulp such as kenaf, straw, bamboo, bagasse and the like, which are usually used as a raw material, are used. It is also possible to appropriately mix and use chemical pulp made of wood as a raw material.
In the present invention in any way, the density of the low density layer selects various pulp so that 0.6 g / cm ³ or less exceed 0.3 g / cm ^3, blended with several kinds as required Shall be used.
In the present invention, it is more desirable that at least one of mechanical pulp, mercerized pulp, and curled fiber is contained in 50% or more of the total pulp of the molded base paper.

In addition, as a pulp fiber which comprises each layer of the shaping | molding raw paper of this invention, the following can be used suitably in the range which does not impair said structure.
As natural pulp fibers constituting the molded base paper of the present invention, wood fibers (chemical pulp, mechanical pulp), non-wood fibers, waste paper pulp and the like are arbitrarily used as necessary.
Among the wood fibers, the chemical pulp includes kraft pulp using caustic soda and sodium sulfide during wood chip cooking, and sulfite pulp using sulfite and bisulfite. These pulps may be unbleached or bleached. Also, 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, refined wood Examples thereof include thermomechanical pulp (TMP) obtained by heating and refining the chip. Of these mechanical pulps, TMP is optimal in terms of the bulkiness and strength of the sheet. In addition, as TMP, C-TMP which refines under pressure after chemically processing a wood chip | tip, BC-TMP etc. which performed the bleaching process etc. shall be included. Of these wood fiber pulps, pulp having a long fiber length obtained from coniferous trees such as pine, larch, cedar, fir and cypress is preferably used for improving the stretchability and strength of the paper sheet. In addition, a pulp having a short fiber length obtained from hardwood such as birch, beech, maple, elm, chestnut can be used in combination as long as the effect of the present invention is not impaired.

  Non-wood fibers that can be used in the present invention include bast fibers such as Kozo, Mitsuma, Ganpi, flax, timer, kenaf, choma, jute, and sun hemp, seed fibers such as cotton and cotton linter, and Manila hemp. And leaf fibers such as sisal hemp and esparto, and stem fibers such as bamboo, rice straw, wheat straw and sugarcane bagasse. In particular, Kozo, Mitsumata, Kenaf, Manila hemp, sisal hemp, cotton, cotton linter and the like are preferably used because they have a long fiber length and can improve the stretchability and strength of the base paper of the present invention. Non-wood fibers can be cooked in the same manner as wood fibers.

  Examples of the used paper pulp that can be used in the present invention include used corrugated cardboard and magazine used paper. In particular, used corrugated paper can improve the stretchability and strength of the paper sheet, and is preferably used.

These pulp fibers can be used alone or in combination of two or more.
Moreover, a synthetic resin fiber can be mixed as needed in the range which does not impair the effect of this invention. Examples of synthetic resin fibers that can be used include polyethylene fibers, polypropylene fibers, polyamide fibers, polyethylene terephthalate fibers, and polybutylene terephthalate fibers.

When making the forming base paper of the present invention, known papermaking chemicals can be appropriately added to each layer.
As papermaking chemicals that can be used, the same sizing agents, paper strength agents, yield improvers, and the like as used in normal papermaking can be used as necessary.
For example, an internal sizing agent such as an alkyl ketene dimer, styrene acrylic resin, or rosin is used as the sizing agent.
Further, paper strength agents and yield improvers include polyacrylamide resin, polyamide epichlorohydrin resin, polyethyleneimine and its derivatives, polyethylene oxide, polyamine, polyamide, polyamide polyamine and its derivatives, cationic and amphoteric starch, oxidized starch, carboxymethyl Organic compounds such as modified starch, plant gum, and polyvinyl alcohol, and inorganic compounds such as sulfate band, alumina sol, colloidal silica, and bentonite can be used in appropriate combination.
They can also be added by spraying between the paper layers during the paper making process, or by coating on the surface of the base paper during or after paper making.

When making the forming base paper of the present invention, a known filler can be appropriately added to each layer.
Fillers include mineral fillers such as talc, kaolin, calcined kaolin, clay, diatomaceous earth, heavy calcium carbonate, magnesium carbonate, aluminum hydroxide, titanium dioxide, magnesium sulfate, silica, aluminosilicate, bentonite, and polystyrene particles. Organic synthetic fillers such as urea formalin resin particles can be appropriately selected and used. Moreover, you may use these in combination arbitrarily.

Furthermore, during papermaking, paper-making additive aids such as dyes, pH adjusters, slime control agents, antifoaming agents, and adhesives can be used as appropriate according to the intended use.
The pH at the time of papermaking of the present invention can be arbitrarily selected between about 4.5 which is acidic papermaking and about 6 to 8 of neutral papermaking as necessary.

The forming base paper of the present invention is carried out using a multi-layered former as in the case of producing general paperboard. Any type of paper machine can be used.
For example, a wet sheet is formed by sequentially laminating pulp slurries corresponding to several tens of g / m ² of dry rice tsubo on a plurality of wire parts of about 10 stations.
More specifically, a pulp layer of about 40 g / m ² is formed on a wire part that first forms a paper layer as an outer layer, dehydrated, and then transferred to a blanket. Next, in the middle layer, a paper layer is similarly formed with another wire part, and the step of laminating the required number of layers on the outer layer is repeated to form the middle layer. Finally, a paper layer as the other outer layer is formed to obtain the molded processed base paper of the present invention.

  In the forming base paper of the present invention, the elongation at break (JIS-P8113) is 5% at least on one side with respect to all the above-mentioned forming base papers in order to prevent cracks generated on the surface of the container during deep drawing. As described above, it is more effective to stack paper sheets that are more preferably 7% or more.

  A molded container with a deeper drawing depth is more stretched during molding than a shallower one, and in particular, the paper layer on the outer side of the molded container is stretched more than the inner side (content side). Therefore, since a high elongation at break is required, the above-mentioned paper sheet having a break elongation of 5% or more is laminated on at least the outermost layer on the side of the outer side of the processing-processed base paper, which is caused by stretching at the time of drawing. It is possible to prevent cracking and the like.

  The pulp used as the raw material of the outermost layer paper sheet can be any of the above-mentioned pulps. Among the wood fiber pulps, long fiber length pulps obtained from conifers such as pine, larch, cedar, fir and cypress are paper. It is suitably used for improving the stretchability and strength of the sheet. Among non-wood fibers, especially mulberry, mitsumata, kenaf, manila hemp, sisal hemp, cotton, cotton linter and the like are long in fiber length and can improve the stretchability and strength of the paper sheet and are preferably used.

  As the papermaking chemicals, the sizing agent, paper strength agent, yield improver, mineral filler, organic rigid filler, dye, pH used in normal papermaking used in the papermaking of the above-described processing base paper of the present invention are used. A regulator, a slime control agent, an antifoaming agent, a sticking agent, and the like can be used as appropriate.

  The outermost layer paper sheet having a high elongation at break can be made by the following paper making process using the raw materials and chemical slurry made of the above materials. That is, in a wet paper machine, a belt that has been stretched in advance by passing a wet paper between the dryer and the belt is attached to a part of the dryer roll via a nip roll to press and rotate an endless thick rubber belt. And the like, and the creping method in which the paper is shrunk by a doctor from a press roll of a paper machine or a processing machine, a cylinder dryer or a Yankee dryer, and the like. Regarding the crepe treatment method, there are various devices and methods such as a doctor device and a position where creping is performed. For example, a crepe is applied by a doctor at a press part of a paper machine called a duo-stress method, and further through a grooved roll at an intermediate part of a dryer. There is a method of giving elongation in the vertical and horizontal directions of paper.

In the present invention, the outermost layer paper sheet obtained from the paper making process may be not only a single layer but also two or more layers of paper. Preferably in the range of 40~300g / ^{m 2} as a basis weight in the range of the outermost layer sheet of paper, more preferably from 50 to 150 g / ^{m 2.} When the basis weight of the outermost layer paper sheet is lower than 40 g / m ² , the tensile strength of the sheet is insufficient and the sheet is easily broken during molding. When the basis weight exceeds 300 g / m ² , The density increases, and the moldability of the crease portion of the molded body is lowered, which is not preferable.

  The outermost layer paper sheet obtained by the above method can be bonded to a paper support via an adhesive to produce a shaped base paper. As a bonding method, a wet lamination method in which a water-based adhesive such as a synthetic resin emulsion, starch, PVA or the like is applied to paper and then pressed and dried with a nip roll, or a hot-melt adhesive that has been heat-melted is applied to paper with a nip roll. Any of a hot melt lamination method in which pressure bonding is performed and an extrusion lamination method in which a thermoplastic resin such as heat-melted polyethylene or polypropylene is formed into a film and spread on paper and then pressure-bonded with a nip roll may be used.

<Other explanation>
The forming base paper of the present invention can be provided with a coating layer comprising a pigment and an adhesive on one side or both sides as required. By providing such a coating layer, good printability can be imparted to the surface of the forming raw paper. Furthermore, it is also possible to provide a printing layer using any ink such as dye ink and pigment ink and using a commonly used printer.
As the pigment used in the coating layer, known pigments such as calcium carbonate, kaolin, clay, talc, titanium oxide, and plastic pigment can be arbitrarily used. As the adhesive used for the coating layer, known ones such as starch, casein, SBR latex, and polyvinyl alcohol can be arbitrarily used. These coating layers can be formed in a single layer or multiple layers. The total coating amount is preferably about ²⁰ to 30 g / m ² .
Further, when such a coating layer is provided, it is more preferable that the layer immediately below the coating layer has a higher beating degree and a smoother surface. Such a coating layer can be applied by appropriately using various known coating apparatuses. Moreover, it is possible to provide a printing layer further on such a coating layer.

The base paper of the present invention can be provided with a water-resistant coating on one or both sides as necessary in order to prevent liquid penetration or liquid leakage. This water-resistant coating can be provided directly on the base paper, on the pigment coating layer, or on the printing layer at an arbitrary location. As a method of providing a water-resistant coating, there are water-resistant paint coating, synthetic resin lamination, and the like, which can be arbitrarily selected according to the situation.
Examples of paints that are coated on the surface of the base paper to provide water resistance include emulsions of waxes such as microcrystalline wax and paraffin wax, latexes such as SBR latex and polyvinylidene chloride latex, acrylic emulsions, self-emulsifying polyolefins, There are various synthetic resin emulsions such as polyethylene copolymer resin emulsions.
The coating equipment for these water-resistant paints may be any commonly used bar coater, air knife coater, roll coater, blade coater, gate roll, size press, etc., and is not particularly limited.

The total coating amount is preferably about 1.0 to 20.0 g / m ² , and these coating layers can be formed in a single layer or multiple layers.
Synthetic resin layers laminated on the surface of the base paper include polyolefin resins such as polyethylene, polypropylene and polymethylpentene, saturated polyester resins such as polyethylene terephthalate and polybutylene terephthalate, polyamide resins such as nylon, ethylene vinyl Examples thereof include alcohol copolymers, polystyrene resins, polyacrylonitrile resins, etc. These synthetic resins are coated with a single substance, or a mixture or laminate of two or more kinds to form a water resistant film. The method of laminating the synthetic resin layer may be any of commonly used wet lamination, hot melt lamination, extrusion lamination, dry lamination, thermal lamination, etc., and is not particularly limited.

  When the drawing is performed at a higher pressing pressure, color irregularities occur in the ruled line portion where the crease is formed on the forming base paper on the container surface, which significantly impairs the cosmetics and may impair the commercial value. In order to solve the problem, it is effective to mix a pigment in the synthetic resin layer.

The blending amount of the pigment in the synthetic resin is preferably in the range of 3 to 40% by weight. If it is less than 3% by weight, the effect of concealing uneven color on the surface of the container may not be sufficiently obtained. On the other hand, when 40 wt% or more is blended, the physical and chemical stability of the synthetic resin is lowered, and it becomes difficult to form a stable synthetic resin layer on the base paper. For example, the occurrence of a neck-in of a molten film in a T-die or a lack due to lack of spreadability of a synthetic resin layer occurs. In addition, when a synthetic resin uses a polyolefin-type resin and a pigment uses a titanium oxide, the compounding quantity of a titanium oxide is 5 to 10 weight% and the US basis weight 15-60 g / m < ² > is preferable.

The above water-resistant paint or synthetic resin may be a biodegradable thermoplastic resin. The biodegradable thermoplastic resin is not particularly limited as long as it is a resin having biodegradability equivalent to or higher than that of paper. That is, 3-hydroxybutyrate-3hydroxyvalerate copolymer, 3-hydroxybutyrate polymer, aliphatic polyester such as polycaprolactone, polyglycolide such as polylactic acid, polyvinyl alcohol, a composite of polyvinyl alcohol and starch, Synthetic or natural resins such as cellulose derivatives such as cellulose acetate can be used alone or in combination. Of these biodegradable thermoplastic resins, a resin particularly suitable for the present invention is an aliphatic polyester. The biodegradable aliphatic polyester is excellent in processability when laminated on a base paper, and is excellent in water resistance of the product.
For the purpose of improving the processability and physical properties of these thermoplastic resins, it is possible to add resins and additives that are not biodegradable or biodegradable to the resins. When adding non-biodegradable resins or additives, it is desirable to add them in a range that does not exceed the weight of the original resin, otherwise the biodegradability of the entire tray will be adversely affected. There is a risk.

Next, press forming of the forming base paper will be described.
<About molding method>
(1) Moisture adjustment of base paper As a method for manufacturing the paper-molded container of the present invention, the base paper for molding is punched into a container blank sheet, ruled lines are put in necessary places, and the blank sheet is applied to a press mold composed of a male mold and a female mold. A manufacturing method called so-called draw forming, in which sandwiching, heating and pressurizing are performed.
At this time, it is preferable that the forming base paper is preconditioned to adjust the water content of the base paper. The moisture content of the base paper is preferably in the range of 10 to 20%, preferably 11 to 17%, more preferably 12 to 15%, and most preferably 12.5 to 14.5%. Here, the moisture of the base paper refers to the weight% of the water with respect to the absolute dry weight of the total pulp in the processed base paper. If the moisture content of the base paper is within this preferred range, plasticization of the forming base paper occurs, the formability is improved, and breakage of the paper layer during molding can be reduced. As a result, it is possible to obtain a drawn container having a greater depth, a smooth and beautiful appearance, and high rigidity. If the water content of the base paper is less than 10%, sufficient rigidity cannot be obtained in the molded body. If the base paper content exceeds 20%, blisters are generated on the forming base paper and the paper layer of the base paper is peeled off. It may take a long time to dry and may cause problems such as reduced productivity.
In addition, as a method of adjusting the moisture of the base paper, there are a method of supplying moisture to the base paper immediately before press molding, a method of transporting and storing in a state where moisture is maintained after moisture is removed from the dryer when paper is made. Can be mentioned.

(2) Forming method Next, the process of manufacturing a forming container from a blank sheet is demonstrated. In the present invention, the drawing is performed by a pair of pressing dies. The pair of heating press molds are a convex mold having a convex shape corresponding to the inner volume of the molded product and a concave mold having a concave shape corresponding to the outer shape of the molded product. The pair of pressing dies can press the molded product by moving at least one of the dies in the front-rear or up-down direction. Hereinafter, for convenience of explanation, a convex mold is used as an upper mold, a concave mold is used as a lower mold, and the upper mold moves downward to perform pressing (FIG. 1).
As a method for heating the blank sheet, a method such as high-frequency heating, hot air heating, or infrared heating may be used. Further, the entire mold may be heated. In this case, a means for heating the mold is required. As the mold heating means, it is common to heat the press mold by providing an electrothermal heating device, but there is also a means for drying by applying a high frequency by connecting a high frequency oscillator to the press mold. . Also, electric heating and high frequency heating can be used in combination.

  Further, the heating temperature at the time of molding is preferably in a range in which the processed base paper is 100 ° C to 150 ° C, more preferably 110 to 140 ° C. If it is less than 100 ° C., it takes time for molding and productivity is lowered. On the other hand, when the temperature exceeds 150 ° C., particularly when the water content of the base paper is high, blistering tends to occur, which is not preferable. The shaped base paper can be brought to the predetermined temperature when set on the heated press machine. As another means, it is also possible to apply a microwave or other electromagnetic wave to a processing base paper containing moisture to raise the temperature and then introduce it into a press machine.

The container that has been drawn may be taken out of the mold and air-cooled. However, in order to improve the dimensional stability, it is also preferable that the high-temperature container is fixed and cooled in a cooling mold for a certain period of time.
As the material for the heating press mold, known materials such as aluminum, aluminum-based alloy, brass, iron, stainless steel, and ceramic can be used.

  As a method of operating the mold, any method of a hydraulic press, an air cylinder, and a cam mechanism can be used. In the present invention, as a specific method for controlling the clearance between the upper die and the lower die, in the case of hydraulic pressure or air pressure, the pressure may be controlled by computer control depending on the thickness of the molded product, or the position of the stopper May be controlled. In the case of using a cam mechanism, it is possible to control by a pre-designed cam shape and mold lowering speed.

About the press pressure at the time of press molding, the range of 10-100 kgf / cm < ² > is preferable. When the pressing pressure is lower than 10 kgf / cm ^2, the compression deformation of the ruled line portion becomes insufficient, and when it exceeds 100 kgf / cm ² , the paper layer of the folded wrinkle portion is destroyed, which is not preferable.
About the press time at the time of press molding, the range of 2-30 seconds is preferable from the point of a moldability and workability | operativity.

<Base paper characteristics under high temperature and high humidity>
Under high-temperature and high-humidity conditions, such as during drawing, the rupture strength (tensile strength) of the formed base paper becomes weak and ruptures with a small force. Further, under high humidity conditions, the higher the temperature, the smaller the elongation at break, that is, the tendency to break easily. For this reason, the tensile properties of the base paper at high temperatures and high humidity are important requirements for drawability, but it is difficult to measure the temperature and moisture of the paper during actual forming. Also, it is not easy to measure the tensile properties of paper under high temperature and high humidity.

However, as a result of research, the present inventors have found that a molding base paper that satisfies the following conditions under conditions of a temperature of 23 ° C. and a moisture content in paper of 14% by weight is suitable for drawing at high temperature and high humidity. I found out.
Longitudinal breaking elongation (JIS-P8113) is 2%, more preferably 3% or more.
The tensile modulus in the machine direction is 1000 to 2000 MPa, more preferably 1200 to 1800 MPa. The moisture content in the paper refers to a value obtained by dividing the moisture weight in the paper by the total weight of the paper (pulp + additive + moisture) at the time of measuring elongation and elastic modulus. When a synthetic resin layer is formed on a paper layer, the above measurement is a measurement in a state where no synthetic resin layer exists.

  If the elongation at break in the machine direction at a temperature of 23 ° C. and a moisture content in the paper of 14% by weight is less than 2.0%, there is a possibility that the film may break due to low stretchability during press forming. There is.

  In addition, when the tensile elastic modulus at a temperature of 23 ° C. and a moisture content in the paper of 14% by weight is set to a range of 2500 MPa or less, the fluidity of the pulp fiber of the forming processed paper is increased, and the paper layer breakage of the folded wrinkle portion at the time of molding is reduced. As a result, a molded body having high strength can be obtained. When the tensile elastic modulus is less than 1000 MPa, there is a possibility that the problem of insufficient rigidity of the molded container may occur. If the configurations of the first and third inventions described above are used, a shaped base paper having the above and the above properties can be easily obtained.

<About the shape of the container>
The container targeted by the present invention is a container obtained by drawing a sheet of paper with a pair of convex and concave press dies, the upper part of the container is open, and the upper edge has a flange. The form is representative. Also, the flange may be curled.

In addition, as described above, the draw-formed container using the molded base paper of the present invention can obtain a product with a smooth surface and a beautiful appearance as compared with those using conventional base paper, etc. Excellent smoothness of flange part.
That is, in the product using the conventional base paper, the uneven step of the flange portion that was 0.20 mm to 0.50 mm can be reduced to a range of 0.03 mm to 0.10 mm in the present invention. Become.
Therefore, when using a sheet-like substrate such as paper or film to cover the opening of a tray-shaped paper molding container having a flange, the sealing performance is extremely good due to the high smoothness of the flange. A highly reliable container can be obtained.

  The outline of the plan view of the container is a square, a rectangle, a circle, an ellipse, or the like. For each shape, the corners are usually rounded. FIG. 2 and FIG. 3 show an example of the drawn container of the present invention as a sketch.

<About container height>
The present invention relates to a forming base paper capable of producing a relatively deep paper drawn container and a manufactured paper molded container. The depth (container height) is related to the container bottom area. A deep-drawn container that satisfies the following formula (1) is prepared, where S1 is the bottom area and H is the height of the paper-molded container made by drawing according to the present invention. It is possible.
(1) Formula: 0.2 ≦ H / (S1) ^1/2

When the container does not have a substantially flat bottom (for example, the shape shown in FIG. 4), a deep-drawn container satisfying the following expression (2) is produced in relation to the height H and the upper opening area S2. It is possible.
(2) Formula: 0.15 ≦ H / (S2) ^1/2
By using the molded base paper of the first to third inventions of the present invention, a deep-drawn container that satisfies the above formula (1) or (2) can be easily obtained.

In addition, in order to form the forming raw paper of the present invention into a shape as a paper molding container, the base paper is divided into a bottom surface and a side surface by a ruled line, without drawing, and the side surface portion is folded and further side surfaces are formed. There is also a method of forming by folding the corners of the parts or by overlapping and gluing (see FIG. 8).
Since the molded base paper of the present invention is bulky, even if the ruled line is deeply inserted, the paper is not torn, and by inserting the ruled line deeply, it becomes difficult to form a gap in the bent and joined portion, resulting in the contents Can prevent leakage. Further, the molded base paper of the present invention can be used as a material for various general paper containers, a material for disposable paper pans, and the like.

  The molded base paper according to the present invention contains natural pulp as a main component and has better formability than conventional molded base paper.

The following examples further illustrate the present invention. In addition, this invention is not limited to an Example below.
Unless otherwise specified, parts by weight are shown in terms of solid content weight.

<Example 1>
Three types of pulp shown in the following (1) to (3) were sequentially combined in this order at a wire speed of 300 m / min using an experimental orientation paper machine manufactured by Kumagai Riki Kogyo.
(1) Commercial NBKP, 450 ml csf, 50 g / m ²
(2) Radiata Pine TMP, 350 ml csf, 180 g / m ²
(3) Commercial NBKP, 450 ml csf, 50 g / m ²
(In addition, each material was beaten to a predetermined freeness by a KRK high-concentration disc refiner type beater manufactured by Kumagai Riki Kogyo Co., Ltd.)
In addition, in the case of combining paper making, starch (trade name: ONL510, manufactured by Oji Corn Starch) is used as an aqueous dispersion having a starch concentration of 2.0% on the front side (felt side) of each layer, and the solid content adhesion is 1.0 g. After spraying so as to be / m ² , the sheets were combined.
Next, the wet-paper-like combined sheet obtained above is sandwiched between a monoplastic canvas sheet (Shikishima canvas) at a nip pressure of 10 kg / cm and a speed of 30 m / min with a calendar (manufactured by Yuri Roll Machinery). To process. The sheet is then dried with a ferro-type cylindrical heating dryer. The sheet was then conditioned at 20 ° C. and 65% RH, calendered with a calender (manufactured by Yuri Roll Machinery) at a nip pressure of 20 kg / cm and a speed of 20 m / min, and then PVA with a concentration of 8.0% ( Kuraray Poval PVA-KL118 (manufactured by Kuraray) was applied by hand at 2.0 g / m ² , and a calender (manufactured by Yuri Roll Machinery Co., Ltd.) with a nip pressure of 40 kg / cm, a speed of 20 m / min, and heat calendering at 120 ° C. This was used as a forming base paper. After adjusting the humidity at 20 ° C. and 65% RH, the base paper, thickness, density, and Z strength Taber stiffness are measured. Further, polypropylene was laminated with a film thickness of 40 μm on the front side of the base paper for molding by melt extrusion to obtain a sheet for paper-made molding container.

The sheet for paper-made container is punched into an oval mold, and ruled lines are stamped radially from the center (see FIG. 5). The paper molding container sheet is heated and pressurized at 130 ° C. and 35 kg / cm ² in a male / female concave and convex paper molding container mold using a test press molding machine (manufactured by Daiichi Koki). A paper molded container having a length of about 20 cm, a short axis of about 14 cm, and a height of about 4 cm was obtained (see FIG. 6).
Assuming a food product in the paper-molded container, after cooling the gelatinized solution obtained by gelatinizing a starch (trade name: Oji Ace A, manufactured by Oji Corn Starch) solution with a concentration of 7% at 70 ° C. to room temperature, 250 g is charged. To do. After confirming that the appearance of the paper-molded container after the gelatinization solution is loaded is normal, and that it has a normal shape, cover the opening with a polyethylene film, and put it in the refrigerator. The plate was left at 12 ° C. for 12 hours, and the degree of swelling and bottom swelling of the appearance of the paper molded container was evaluated and judged by the method described later.

<Example 2>
The following three types of pulp are used, and when the coating is applied to the surface, the coating liquid shown below is used, and the weight after drying by hand coating with a Mayer bar is 9.0 g / m ² , and the top coat Coated paper was made in the same manner as in Example 2-1, except that coating was performed at 10.0 g / m ² and drying was performed in a hot air dryer (manufactured by Advantech) at 105 ° C. for 60 seconds.
(1) Commercial NBKP, 450 ml csf, 50 g / m ²
(2) Radiata Pine TMP 300 ml csf / commercial NBKP, 150 ml csf product = 70/30, blended freeness 280 ml csf, 230 g / m ²
(3) Commercial NBKP 450 ml csf, 50 g / m ²
[Contains paint]
Topcoat: Kaolin (trade name: Ultra White 90, manufactured by Engelhard) / Calcium carbonate (trade name: Brilliant, manufactured by Shiroishi Kogyo) / Titanium oxide (trade name: TCA333, manufactured by Tochem Products) = 50/35/15 And latex (trade name: L1410, manufactured by Asahi Kasei) / urea phosphate esterified starch (trade name: MS4600, manufactured by Nippon Shokuhin Kako) = 15/5. (Number of blending parts based on weight of solid content, the same shall apply hereinafter)
Undercoat: Kaolin (trade name: Kaoblite, manufactured by Seal) / Calcium carbonate (trade name: Softon 2200, manufactured by Bihoku Powder) = 50/50, and Latex (trade name: 0668, manufactured by JSR) / Urea phosphate ester Chemical starch (trade name: MS4600, manufactured by Nippon Shokuhin Kako) = 15/5.
Subsequently, the sheet | seat for paper molding containers and the paper molding container were obtained exactly like Example 1, and it measured and evaluated similarly.

<Example 3>
Except for using the three types of pulp shown below, paper was made in the same manner as in Example 1.
(1) Commercial NBKP, 450 ml csf, 50 g / m ²
(2) Radiata pine TMP, 350 ml csf / commercial LBKP, 350 ml csf product = 70/30, blended freeness 350 ml csf, 200 g / m ²
(3) Commercial NBKP 380 ml csf, 50 g / m ²
Next, a shaped base paper was obtained in exactly the same manner as in Example 1, and after adjusting the humidity at 20 ° C. and 65% RH, the basis weight, thickness, density, and Z strength Taber stiffness were measured. Next, in the same manner as in Example 2-1, polypropylene lamination was performed on the front surface to obtain a sheet for paper molding container, and the sheet was punched into the shape shown in FIG. 7 to form ruled lines, and further according to the ruled lines After assembling and bonding, a box-shaped container having a long side of about 20 cm, a short side of about 14 cm, and a height of about 4 cm as shown in FIG. 8 was obtained, and similarly measured and evaluated.

<Example 4>
Except for using the three types of pulp shown below, paper was made in the same manner as in Example 2-1.
(1) Commercial NBKP, 450 ml csf, 50 g / m ²
(2) Commercial mercerized pulp 300 ml csf / commercial NBKP, 150 ml csf product = 70/30, blended freeness 250 ml csf, 200 g / m ²
(3) Commercial NBKP 450 ml csf, 50 g / m ²
Subsequently, the sheet | seat for paper molding containers and the paper molding container were obtained exactly like Example 1, and it measured and evaluated similarly.

<Example 5>
Except for using the three types of pulp shown below, paper was made in the same manner as in Example 1.
(1) Commercial NBKP, 450 ml csf, 50 g / m ²
(2) Commercial NBKP, 150 ml csf product / Curled fiber (made by Warehauser) 750 ml csf product = 70/30, freeness after blending 300 ml csf, 160 g / m ²
(3) Commercial NBKP 450 ml csf, 40 g / m ²
Subsequently, the sheet | seat for paper molding containers and the paper molding container were obtained exactly like Example 1, and it measured and evaluated similarly.

<Example 6>
Except for using the three types of pulp shown below, paper was made in the same manner as in Example 1.
(1) Commercial NBKP, 450 ml csf, 50 g / m ²
(2) Kenaf TMP, 350 ml csf, 185 g / m ²
(3) Commercial NBKP, 380 ml csf, 50 g / m ²
Subsequently, the sheet | seat for paper molding containers and the paper molding container were obtained exactly like Example 1, and it measured and evaluated similarly.

<Comparative Example 1>
Papermaking was performed in the same manner as in Example 2-1, except that the following kind of pulp was used and only one layer was used.
Commercial NBKP, 450mlcsf, 350g / m ²
Subsequently, a molding base paper and a paper molding container were obtained in exactly the same manner as in Example 1, and the measurement and evaluation were performed in the same manner.

<Comparative example 2>
Papermaking was performed in the same manner as in Example 1 except that the following two types of pulp were used and only two layers were used.
(1) Commercial NBKP, 450 ml csf, 50 g / m ²
(2) Commercial NBKP, 450 ml csf, 200 g / m ²
Subsequently, the sheet | seat for paper molding containers and the paper molding container were obtained exactly like Example 1, and it measured and evaluated similarly.

<Comparative Example 3>
Papermaking was performed in the same manner as in Example 1 except that the following three types of pulp were used.
(1) Commercial NBKP, 450 ml csf, 28 g / m ²
(2) Radiata Pine TMP, 350 ml csf, 28 g / m ²
(3) Commercial NBKP, 450 ml csf, 28 g / m ²
Next, a sheet for paper molding container and a box molding container were obtained in exactly the same manner as in Example 3, and measurement and evaluation were performed in the same manner.

<Comparative example 4>
Papermaking was performed in the same manner as in Example 2-1, except that the following kind of pulp was used and only one layer was used.
Commercial NBKP, 450mlcsf, 360g / m ²
Subsequently, the sheet | seat for paper molding containers and the paper molding container were obtained exactly like Example 1, and it measured and evaluated similarly.

  Tables 1 and 2 show the measurement and evaluation results of Examples and Reference Examples. The evaluation method is as follows.

[Density of each paper layer]
The peel strength test method of the paper sheet making layer of JIS P 8139 is peeled by the delamination method described in the method, and the thickness (mm) and the basis weight (g / m ² ) are determined. In addition, since the thickness of each peeled layer is fluffed by peeling and becomes thicker than the actual thickness, the correction factor value is calculated by the following method, the thickness value of each layer after peeling is corrected, and each layer The density of is calculated.
Correction factor value = total layer thickness before peeling / total value of each layer thickness after peeling Peeling of each layer is difficult with the delamination method described in the above-mentioned JIS P 8139 paperboard bonding layer peeling strength test method In such a case, the multi-layered sheet sample is immersed in warm water at 60 ° C. for 1 hour, and then separated into a surface layer, a middle layer, and a back layer. Each peeled layer is dried to determine the thickness (mm) and basis weight (g / m ² ). Thereafter, the correction factor value is similarly calculated to correct the thickness of each peeled layer, and the density of each layer is calculated.

(Judgment rate judgment)
The outer peripheral value of the central portion of the paper tray body is measured, and the difference between the normal state before the evaluation test and the outer peripheral value of each central portion of the body after 12 hours is measured to calculate the swelling rate.
Body swelling rate% = (body center outer periphery value after 12 hours-body center outer periphery value before evaluation test) / body center outer periphery value before evaluation test. Those with 1.5 to 3.0% were judged as x, and those with less than 1.5% were judged as good.

<Example 7>
Using a disc refiner, commercial NBKP was beaten to 550 ml csf (Tappi T-227 Canadian standard type) and Radiatapine TMP was beaten to 300 ml csf. Using these as paper stock, a paper support comprising a two-layer structure of a first layer NBKP 40 g / m ² and a second layer TMP 250 g / m ² was made using a multi-layered paper machine (the density of each layer of the support is See Table 3 below).

Bleached kraft stretched paper (basis weight 75 g / m ² , made by Oji Paper Co., Ltd.) was bonded to the paper support as an outer layer sheet to form a processed base paper. Bonding was performed according to the following procedure. Immediately after applying 20 g / m ² of EVA emulsion adhesive (trade name: Vinizol 1412 modified, manufactured by Daido Kasei) with a Mayer bar on the surface of the TMP layer of the paperboard, this undried coating layer The bleached kraft stretch paper was pressure-bonded with a hand roll, and dried with a hot air dryer at 110 ° C. for 20 seconds. The molded base paper thus obtained was evaluated for elongation at break and formability by the test methods described below.

<Example 8>
Produced and evaluated base paper in the same manner as in Example 7 except that the outer layer sheet to be bonded to the paper support was unbleached kraft stretch paper for cement bags (basis weight 83 g / m ² , made by Oji Paper) 83 did.

<Example 9>
A processed base paper was produced and evaluated in the same manner as in Example 7 except that the second layer of the paper support was TMP 180 g / m ² and the outer layer sheet to be bonded to the paper support was a kraft stretched paper for adhesive tape. .

<Reference Example 1>
A paper having a basis weight of 70 g / m ² was made from a paper stock obtained by beating commercial NBKP to 640 mlcsf with a disc refiner, and dried at 110 ° C. with a rotary dryer. Molded base paper was produced and evaluated in the same manner as in Example 7 except that this handmade paper was used as an outer layer sheet to be bonded to a paper support.

<Evaluation methods>
(1) Elongation at break After the specimens cut to 15 mm width and 250 mm length in each of the flow direction and the width direction were conditioned at 23 ° C. and 50% RH for 24 hours or more, the strograph M2 type tester (Toyo Seiki) Measured at a tensile speed of 20 mm / min according to JIS-P8113.
(2) Formability Water vapor was applied to the forming base paper and humidity was adjusted to 12% moisture in the paper, punched into a circular shape, and ruled lines were engraved radially from the center to obtain a blank sheet. The blank sheet was heated and pressed at 130 ° C. and 35 kg / cm ² in a male and female cup-shaped mold by using a test press molding machine (manufactured by Daiichi Koki). Was a circular shape having a diameter of 12 cm, a bottom surface portion having a circular shape having a diameter of 6 cm, a flange portion having a width of 0.8 cm, and a cup-shaped drawn body having a curved surface from the side wall to the bottom surface (FIG. 9).
At this time, it shape | molded so that the outer-layer sheet bonding side might become the outer side of a molded object.
And the moldability at this time was evaluated as follows.
○: Can be molded into a cup shape, the outer layer of the molded body is not torn, and the surface of the molded body is smooth.
Δ: Can be molded into a cup shape, but the outer layer of the molded body is broken.
The evaluation results are shown in Table 4.

  According to Table 4, the base paper of the present invention in which an outer layer sheet having an elongation at break of 5% or more is laminated as an outer layer sheet is cracked or torn on the surface of the outer paper layer during molding even for a deeply drawn sheet such as a cup. It does not occur and it can be seen that the moldability is excellent.

Schematic diagram of drawing method by press Perspective view of an embodiment of the present invention Perspective view of an embodiment of the present invention Perspective view of an embodiment of the present invention Blank sheet plan view of squeezed paper molding container Perspective view of squeezed paper molding container Blank sheet plan view of box molding container Perspective view of box-molded container Perspective view of an embodiment of the present invention

Explanation of symbols

1. Male type Female type 3. Formed base paper Ruled line

Claims (6)

Dense layer of density 0.7~0.9g / cm ^3, and has a low density layer of the Density 0.3-0.6 g / cm ^3, a basis weight is 100 to 500 g / ^{m 2,} the overall density A molded base paper, characterized in that the low-density layer is mainly composed of pulp selected from at least one of mechanical pulp, curled fiber, and mercerized pulp, 0.4 to 0.7 g / cm ³ .   2. The molded base paper according to claim 1, wherein the low-density layer is mainly composed of mechanical pulp.   3. The molded base paper according to claim 1, wherein a paper sheet having a breaking elongation (JIS-P8113) of 5% or more is laminated on at least one side.   A paper-molded container using the molded base paper according to any one of claims 1 to 3.   The paper molded container according to claim 4, which is formed by drawing. The forming-processed base paper according to any one of claims 1 to 3 is manufactured by drawing using a pressing die at a temperature of 100 to 150 ° C and a pressing pressure of 10 to 100 kgf / cm ^2. A method for manufacturing a paper molded container.

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