JP5987360B2 - Method for producing water-resistant barrier paper cup - Google Patents

Description

  The present invention relates to a paper cup having barrier properties and water resistance capable of hot water retorting.

  A cup-shaped paper container that is filled with beverages such as juice and the upper opening is sealed with a lid. A laminated material with a thermoplastic resin layer such as polyethylene on both sides with paper as the base material has a specified shape. In general, a paper cup was formed by punching a blank into a body part and providing a bonding part on the body part.

  Further, when a barrier property against a gas such as oxygen or water vapor is required, as the constituent material of the body portion, for example, from the front side, polyethylene / paper / polyethylene / aluminum foil / polyethylene terephthalate film / polyethylene or polyethylene / paper / Often used are paper cups molded with a laminate material such as polyethylene / metal oxide deposited plastic film / polyethylene.

One of the problems with such paper cups is ensuring resistance to moisture and gas penetration from the outside, and the other is preventing the occurrence of peeling or pinholes during processing or use of laminated materials. is there. In particular, in a laminated material including paper in the layer structure, various ideas have been made to avoid exposing the end face of the paper.
For example, in order to secure the barrier property of the joint portion of the paper cup, as an end face processing (edge protection) method for protecting both end faces of the joint portion of the trunk member constituting the trunk portion of the paper cup, FIG. ) To (c), a method called skive hemming is also known.

  In this method, the outermost layer edge of the body member (100) made of a laminated sheet as shown in FIG. 7 (a) in which a thermoplastic resin (102) is laminated on a paper base (101) is cut by a milling method or a cutting bell knife. About half of the thickness of the body member (100) is skived (cut) as shown in FIG. Next, the remaining half of the skived is hemmed (turned back) so that the deleted surface is on the inside, and the paper end surface is protected with a thermoplastic resin as shown in FIG. 7C.

  In order to perform a skive hemming process on the paper end surface, it is necessary to perform a skive hemming process on the paper end surface using a special processing machine before forming a blank body member blank into a paper cup. Further, since it is necessary to align the skive end faces in a straight line, it is difficult to perform cup molding simultaneously with skive hemming with a cup molding machine. Thus, the skive hemming process has to go through complicated processing steps, and further, paper dust is generated because the paper is skived (cut), and it is difficult to completely remove the paper dust.

  Further, the skive hemming process has a problem that the skive depth is difficult to control and a cut from the skive portion may occur after molding, and the side seals and the like are not stable. In addition, since paste is used for the return bonding after skiving in skive hemming, it is difficult to manage the amount and position of the paste.

  End surface processing for producing a paper cup with excellent barrier properties by protecting the end surfaces at both ends of the joint portion of the body member constituting the body portion of the paper cup without performing the skive hemming process having such problems As a method, a method of manufacturing a paper cup using a blank whose end surface is covered by extending a water- and oil-resistant thermoplastic film covering the surface of a paper substrate has been proposed (for example, see Patent Document 1). .

  In the paper cup having a barrier property that protects the end face of the paper base material, the inner edge of the body bonding portion is formed by extending the thermoplastic resin layer from the paper base material over the whole. As described above, the film of the thermoplastic resin layer extending from the paper base material is irregularly formed when cup-molding, and the end surface of the paper base material which is the original purpose cannot be sufficiently covered. There was a thing. In addition, there is a problem that the finish as a paper cup is poor and the appearance is not good. In addition, since the thermoplastic resin layer is required to have a sealant property of heat sealability at the time of molding as well as water and oil resistance and steam barrier properties, mechanical strength tends to be neglected.

  Further, a laminated sheet having a paper base material having a thermoplastic resin layer on at least the inner surface is punched into a predetermined shape, and a resin portion extending outwardly on one side edge is formed along the end face of the base material. Thus, a paper container has been proposed in which a body-laminated portion is formed by superimposing and closely adhering a close-coated blank so as to be inside the other side edge (see Patent Document 2).

  In this paper container, in the case of a cup-shaped container, the flange portion is formed by winding the upper end edge of the body member into the opening, so the difference in thickness on the upper surface of the flange portion due to the difference in the overlap of paper on the base material. A stepped portion due to is generated. For this reason, when a cover material is stacked on the upper surface of the flange portion and heat-sealed as it is, the stepped portion cannot be reliably sealed. In particular, when the flange portion is in a flat state, the influence of the thickness of the base material was large.

  Further, in order to securely seal with the lid member, a filling member made of another resin or the like for filling the stepped portion on the upper surface of the flange portion is provided, and the position of the stepped portion is sealed to eliminate the stepped portion. The seal had to be done partially.

  Further, a folded resin part obtained by punching a laminated sheet having a thermoplastic resin layer on the inner surface as a base material into a predetermined shape and folding the resin part extending outward to one side edge to the outer surface side A paper container has also been proposed in which a body-laminated portion is formed by stacking a blank having a thickness so as to be inside the other side edge and closely contacting a base material (see Patent Document 3).

  In this paper container, the inner surface side base material end face in the bonding portion is protected by being covered with a thermoplastic resin layer. In Patent Document 3, in the case of a cup-shaped container, the flange portion is formed by winding the upper end edge of the body member into the opening portion, so that a step portion due to the thickness of the base material paper does not occur. There is also a solution in which a part of the upper end edge of the body member blank is cut off so that the sealing can be reliably performed even if the cover material is stacked on the upper surface of the material and heat-sealed as it is.

  As a method for preventing deterioration due to moisture permeation from the end face of the paper used for the container, there is proposed a method for achieving this object by improving the water resistance of the paper itself in addition to the method of covering the end face with a plastic film. ing.

In Patent Document 4, the body and bottom blank plates include at least the outermost heat-resistant thermoadhesive resin layer, the intermediate layer of the base paper and the gas barrier layer, and the innermost heat-resistant thermoadhesive resin layer. A retort sterilization treatment using a base paper that is formed of a laminated sheet and has a rice basis weight of 150 to 400 g / m ^{2 in} a cup base paper, and the glass base paper has a steecht size of 400 seconds or more. Possible paper cups have been proposed.
When the Stekichto sizing degree is less than 400 seconds, the water resistance of the cup base paper is insufficient, and the end surface of the edge of the laminated sheet is exposed to the outside. It is said that it penetrates into the inside and causes a swell phenomenon, and deformation of the container is also recognized due to a decrease in rigidity.

  Here, paper that does not easily penetrate hot water is used, but it is difficult to completely prevent the penetration of hot water under high-pressure conditions that can be applied during retort sterilization. In addition, a base paper having a number of seconds that is more than double the normal size as an index of moisture permeability is required, and special paper must be used, so there are also problems in terms of economy and processing technology.

There has also been proposed an attempt to make a cup-like container that can withstand hot water during retort sterilization by using paper that has been processed so that its strength does not easily decrease even when immersed in hot water.
As a method that does not require special paper, Patent Document 5 discloses α-methylstyrene, methyl methacrylate, and carboxyl groups that can provide coating properties excellent in heat resistance, water resistance, friction resistance, and retort resistance. It has been proposed to impart durability by applying an aqueous acrylic resin containing an ethylenically unsaturated compound having an essential component to a paper substrate.

  Furthermore, Patent Document 5 uses a combination of introducing a polyisocyanate compound into a fiber structure of a paper base material by impregnation, forming a film on the fiber itself, and fixing the entangled portion of the fiber to form water and a urea compound. It has also been proposed to do. Since the produced urea compound is excellent in water resistance and heat resistance, it is said that extremely high dry strength, wet strength, and hot water resistance can be imparted to the fiber structure as the impregnated product.

According to this method, for example, even if hot water permeates into the paper base material during retort sterilization, the container is not destroyed because the paper base material is provided with extremely high wet strength and hot water resistance.
However, since water vapor permeability is necessary to evaporate the internal water vapor in the process of evaporating the hot water that has penetrated into the paper substrate during retort sterilization at high temperature and high pressure, the printability of the paper substrate surface is improved. There is a limit to the formation of a coating layer for securing, and there are cases in which a beautiful container cannot be obtained.

  Patent Document 6 includes a top material, a side material, and a bottom material, and curls the top and bottom end portions of the side material on the inside or outside of the container when forming a portion that bonds the side material and the top material. In this process, a paper container having a structure in which the edge of the side material end is not exposed to the outside of the container by curling the end of the side material one or more times has been proposed. And the end surface of the bottom body side material of the bottom is securely sealed to prevent penetration of hot water or the like from the end surface.

As mentioned above, many proposals to prevent moisture penetration from the end face of the paper base to enhance the barrier properties of the liquid paper container until it can withstand the hot water retort treatment. The challenge of ensuring resistance to the situation is making some progress.
However, another problem in the case of such a paper cup is the prevention of occurrence of peeling or pinholes of the laminated material during processing or use. Against this background, various ideas have been made.

  Among the problems caused by the insufficient mechanical strength of the thermoplastic resin layer provided on the surface of the paper substrate, the serious problem is that the necessary barrier properties are lost due to holes such as pinholes and cracks generated by damage during molding. In other words, the hot water retort process, which is particularly severe in terms of hot water and pressure, cannot be tolerated.

  In the process of forming the bottom of the container, a typical example of the damage during the molding of the paper cup is that the bottom of the barrel member formed in a cylindrical shape is the outer peripheral edge of the bottom member (bottom material) placed on the mold (standing upright) Part), when the die hits the outer periphery of the bottom part of the body member when it is curled (bottom in curl), the surface thermoplastic resin layer is scraped to create a hole, and retort treatment is performed by the penetration of hot water from this hole Sometimes the base paper swells.

  Further, even in the caulking work process in which the bottom of the body member curled inward is crimped so as to sandwich the outer periphery of the bottom member, the knurl that rotates while pressing the body member bottom from the inside to the bottom member standing part or the expansion that expands from the inside. The thermoplastic resin layer may be cut by the eyes to form holes, and the base paper may swell during retort processing due to the penetration of hot water from the holes.

  In response to the above-mentioned problem that occurs when the body member is curled, the surface of the thermoplastic resin layer is scraped to form holes, and the layer constituting the thermoplastic resin layer has high mechanical strength. For example, stretched polyethylene Several techniques for preventing the formation of holes during cup molding by using a plastic film such as a terephthalate resin film have been proposed.

  For example, by providing a polyethylene terephthalate layer or nylon layer with excellent heat resistance and friction resistance sandwiched between sealant layers on the container outer surface side of the body member of a cup-shaped paper container, There has been proposed a cup-shaped paper container that prevents the occurrence of flaws and has a resistance to hot water permeation, and that can maintain a barrier property that enables hot water retort treatment (Japanese Patent Application No. 2010-051476: not yet). Release).

  In addition, by forming a heat-resistant and abrasion-resistant resin layer consisting of a polyethylene terephthalate layer or nylon layer with excellent heat resistance and abrasion resistance, which is laminated on the outer surface of the base material of the body member of the paper cup, by the dry lamination method, Has been proposed (Japanese Patent Application No. 2010-139226: unpublished), which has improved the adhesiveness of the sealant layer while maintaining the moldability.

  Furthermore, using a non-stretched polypropylene (CPP) resin layer with a mixed layer of polypropylene (PP) resin and polyethylene (PE) resin as the sealant layer, medium density polyethylene (MDPE) resin or acid-modified medium density It has been proposed to improve the adhesion of the sealant layer while maintaining the moldability by extrusion lamination with a polyethylene resin (Japanese Patent Application No. 2010-160524: unpublished).

  By providing a heat-resistant and wear-resistant resin layer on the body of the paper cup by the dry lamination method, we have improved the adhesiveness of the sealant layer while maintaining the moldability during cup molding, and then proceeded to hot water retort processing Several solutions have been shown to improve the resistance of the film, but the following problems have been left in view of maintaining barrier properties.

When only the thermoplastic resin layer provided on the surface of the paper substrate is insufficient in barrier properties, a laminate in which a metal or inorganic compound vapor deposition layer is provided on a plastic film is often used as a gas barrier layer.
In this case, the vapor deposition layer is often less extensible and generally has a thin vapor deposition thickness, and in the molding process as described above, it has the property of being easily broken and perforated, and a necessary barrier even after molding. It is not easy to secure the sex.

  A layer having a barrier property such as a metal or inorganic compound vapor deposition layer may be included in the thermoplastic resin layer protruding from the side edge of the body member during the paper cup molding process, and the step of bending the thermoplastic resin layer However, a similar problem may occur (see FIG. 6). (Japanese Patent Application No. 2011-027013: Unpublished).

Here, as a paper cup capable of hot water retort treatment that can maintain barrier properties including water shielding of the paper surface coating as well as the paper end surface of the base material during the molding process, the barrier laminated on the base material inner surface of the trunk member Even if there is a crack in the vapor-deposited film of the gas barrier layer at the time of container molding by providing a protective layer made of a resin layer with excellent properties on the paper base side of the gas barrier layer made of metal or inorganic compound vapor-deposited plastic film Moisture penetrating from cracks can be blocked, which prevents the occurrence of flaws on the surface of the barrel member during cup molding, and the hot water retort treatment is highly resistant to hot water penetration. It is possible to maintain the possible water resistance.

In the configuration as described above, the number of layers constituting the laminated material is large. Therefore, the material cost and process cost are increased, the yield is not increased, and the heat resistance of the adhesive or the adhesive layer for laminating is insufficient. If the adhesive or adhesive layer is softened by the heat when heating in the process of forming the body part bonding part or the process of attaching the body part and the bottom part, the moisture contained in the paper substrate As a result of the vaporization of water, the paper substrate and the PET film, for example, are separated from each other.

Japanese Patent Laid-Open No. 51-122666 JP 2005-272010 A JP 2008-222245 A JP 2005-35574 A JP 2003-26980 A JP 2009-230238 A

  When molding a container having excellent barrier properties using a body member in which a side edge located at an overlapping portion is formed by protruding a resin portion film made of an extended thermoplastic resin layer. It was made in view of the above problems, and the adhesive or adhesive layer was softened by the heat at the time of cup molding, and with the water vaporization of the water contained in the paper base, It is an object of the present invention to provide a paper cup capable of being subjected to hot water retort treatment that prevents the phenomenon of peeling between the layers of the film and maintains barrier properties including water shielding of not only the paper end face of the substrate but also the paper surface.

  In the present invention, a water vapor barrier layer made of a thermoplastic resin layer having excellent heat resistance is extruded and laminated on the paper base side of a gas barrier layer made of a metal or inorganic compound vapor-deposited plastic film on the inner surface of a paper base of a body member of a paper cup. By providing by the method, it prevents the phenomenon of peeling between the paper substrate and the film layer due to the water vaporization of the water contained in the paper substrate due to the heat at the time of cup molding, This paper cup has a high resistance to the osmotic force of water and can maintain water resistance that can be treated with a hot water retort.

The invention according to claim 1 of the present invention is a cylinder in which one side edge of a blank composed of a laminated sheet in which a thermoplastic resin layer is provided on an inner surface and an outer surface of a paper base material is superimposed on the other side edge. the method of manufacturing a paper cup with a part bonding unit, a thermoplastic resin layer provided on at least the inner surface, the body portion by laminating a paper substrate via a polyethylene terephthalate or polybutylene terephthalate, which is provided by extrusion lamination A method of forming,
A method for producing a water-resistant barrier paper cup , wherein the thermoplastic resin layer provided on the inner surface includes a sealant layer, and the polyethylene terephthalate or polybutylene terephthalate has a higher melting point than the sealant layer. is there.

According the invention of claim 2 of the present invention, the thermoplastic resin layer provided on the outer surface, characterized in that laminated to the paper substrate through a polyethylene terephthalate or polybutylene terephthalate, which is provided by extrusion lamination Item 2. A method for producing a barrier paper cup having water resistance according to Item 1.

The invention according to claim 3 of the present invention is the method for producing a barrier paper cup having water resistance according to claim 1 or 2, wherein the thermoplastic resin layer on the inner surface includes a gas barrier layer.

In the invention of claim 4 of the present invention, the gas barrier layer is made of an ethylene-vinyl alcohol copolymer, MDX nylon, a polyvinylidene chloride film, a polyethylene terephthalate film coated with a polyacrylic acid resin, or a metal or metal oxide thereof. The method for producing a barrier paper cup having water resistance according to claim 3, comprising a film on which an inorganic oxide is deposited.

The invention according to claim 5 of the present invention is such that the side edge located inside the body bonding part of the blank has a resin part extending from the side edge of the paper base on the outer surface side of the base. The side end edge that has a folded back resin portion and is located outside the body portion bonding portion of the blank has a resin portion that extends from the side end edge of the paper base material. It is a manufacturing method of the barrier paper cup which has the water resistance of any one of 1-4.

In the invention of claim 6 of the present invention, the resin portion extending from the side edge located outside the body bonding portion of the blank is a folded resin portion folded back to the outer surface side or the inner surface side of the paper substrate. It is a manufacturing method of the barrier paper cup which has the water resistance of Claim 5 characterized by having.

In the invention according to claim 7 of the present invention, the resin portion extending from the side edge located outside the body bonding portion of the blank is in close contact with the inner blank of the body bonding portion. It is a manufacturing method of the barrier paper cup which has the water resistance of Claim 5 or 6 characterized by the above-mentioned.

Invention of claim 8 of the present invention, the inner and or resin portion extending from a side edge located on the outside, characterized in that provided on the entire length of the side edge, from the claims 5 7 The method for producing a barrier paper cup having water resistance according to any one of the above.

  According to the first aspect of the present invention, at least the thermoplastic resin layer provided on the inner surface is made of paper via polyethylene terephthalate or polybutylene terephthalate having a melting point higher than that of the sealant layer provided by extrusion lamination. By laminating on the base material, the following problems caused by hot pressure for laminating at the time of production when laminating on the paper base material layer by the extrusion laminating method are effectively avoided and used as a sealant layer. A polypropylene resin having a heat melting property and necessary heat resistance can be effectively used as the sealant layer.

  When the extrusion laminating method is used as a method of laminating a thermoplastic resin layer on paper as a base material, a resin (for example, polyethylene) having a melting point lower than the melting point of the resin (for example, polypropylene resin) used for the outermost sealant layer In many cases, the resin is formed into a layer by thermally melting between a base material and, for example, a polyethylene terephthalate layer.

  When molding into a cup shape using a laminate of such a configuration, it is necessary to heat melt the outer sealant layer at the blanks end and weld it to the inner surface. When a low melting point polyethylene resin or the like between a paper substrate and a film layer such as polyethylene terephthalate is melted and foamed by evaporation of moisture generated from the heated paper substrate, an air layer is formed, and the heat that floats It happens that the plastic resin layer is heated strongly, and a hole such as a pinhole that destroys the sealing property is likely to be generated.

  In order to prevent the occurrence of defects as described above in bonding at the time of cup molding, extrusion lamination of polyethylene terephthalate resin or polybutylene terephthalate resin having a melting point higher than that of the sealant layer is used for adhesion between the paper base and the thermoplastic resin layer. It is effective to use the method.

  According to the invention of claim 2 of the present invention, the thermoplastic resin layer provided on the outer surface is also laminated on the paper base material via polyethylene terephthalate or polybutylene terephthalate by the extrusion laminating method. Water vapor diffusing from both sides of the substrate can be completely blocked.

  According to the invention of claim 3 of the present invention, since the thermoplastic resin layer on the inner surface includes a gas barrier layer, it becomes a paper cup capable of suppressing deterioration of the contents due to oxygen, alteration due to water vapor, and the like.

According to the invention of claim 4 of the present invention, the gas barrier layer is made of an ethylene-vinyl alcohol copolymer, MDX nylon, a polyvinylidene chloride film, a polyethylene terephthalate film coated with a polyacrylic acid resin, or a metal or metal By comprising a film on which an inorganic oxide such as oxide or silicon oxide is deposited, it is more reliable to ensure barrier properties and prevent the penetration of hot water into the paper substrate layer due to scratches and pinholes in the thermoplastic resin layer. Will be possible.
It is particularly important in a process including retort sterilization using hot water to stably and reliably prevent the penetration of hot water into the paper base material layer.

  According to the invention which concerns on Claim 5 of this invention, the side edge located inside the side edge overlapping part of a trunk | drum member blank is a paper base extended from the side edge of a paper base material. It has a folded resin part folded on the outer surface side of the material, and the side edge located outside the overlapping part of the blank has a resin part extending from the side edge of the paper base, In the state where the outer surface side base material end face in the mating part is overlaid, a stepped part is generated in the body part pasting part, which is not only in appearance, but also water penetration from the outside is likely to occur due to wrinkles etc. at the time of overlaying Can be eliminated.

  According to the sixth aspect of the present invention, the resin portion extending from the side edge located outside the overlapping portion of the blank is folded back to the outer surface side or the inner surface side of the paper base. In addition to ensuring that the edge of the paper base material can be sealed, it is possible to ensure the amount of resin in the body bonded portion, and in the case of a thermoplastic resin layer including a gas barrier layer, A paper cup whose end face is not exposed is obtained (see FIG. 3).

  According to the invention which concerns on Claim 7 of this invention, the resin part extended from the side edge located in the outer side of the overlapping part of the said blank is closely_contact | adhered along the blank inside the said overlapping part. As a result, a paper cup can be obtained that not only reliably seals the end of the paper base material but also ensures the amount of resin in the body bonded portion (see FIG. 4).

  According to the invention according to claim 8 of the present invention, the resin portion extending from the side edge located on the inside and / or outside is provided on the entire length of the side edge, so that the body portion other than the flange portion is bonded. A paper cup with excellent sealing performance of the part is obtained (see FIG. 5).

It is explanatory drawing which shows the manufacturing process of a cup-shaped container. It is sectional explanatory drawing which shows the layer structural example of a trunk | drum member. (A) shows a configuration in which the inner thermoplastic resin layer is laminated with PET or PBT, and (b) shows a configuration in which the outer thermoplastic resin layer is also laminated with PET or PBT. It is sectional explanatory drawing which shows the example of a trunk | drum bonding part. It is sectional explanatory drawing which shows the example of a trunk | drum bonding part. The 2nd punching process which punches the trunk | drum member blank which has a resin part used for manufacture of a paper cup in a defined shape is shown, (a) is plane explanatory drawing, (b) is the AA 'line cross section of (a). It is explanatory drawing. It is sectional explanatory drawing which shows the example of a trunk | drum bonding part. It is sectional explanatory drawing which shows the example of a skive hemming process.

Embodiment examples of the water-resistant barrier paper cup of the present invention will be described in detail below with reference to the drawings as necessary.
FIG. 1 is an explanatory view showing the manufacturing process of the cup-shaped container, and FIG. 2 is a simple cross-sectional explanatory view showing an example of the layer structure of the body member blank used in the barrier paper cup having water resistance of the present invention. FIG. 2 (a) shows a configuration in which the inner thermoplastic resin layer is laminated with PET or PBT, and FIG. 2 (b) shows a configuration in which the outer thermoplastic resin layer is also laminated with PET or PBT. Parts that are not directly related to the explanation are omitted.

  In the barrier paper cup having water resistance according to the present invention, one side edge of a blank composed of a laminated sheet in which a thermoplastic resin layer is provided on the inner surface and the outer surface of a paper base material is overlapped with the other side edge. In a paper cup having a body bonded portion, at least a thermoplastic resin layer provided on the inner surface is laminated on a paper substrate via polyethylene terephthalate (PET) or polybutylene terephthalate (PBT) provided by an extrusion laminating method. It is the barrier paper cup which has the water resistance characterized by being characterized.

FIG. 2 shows an example of a horizontal cross section (for example, a cross section taken along line AA ′ of FIG. 5) of a blank used as the body member (which may also be used as a bottom member).
FIG. 2A shows an example of a configuration in which the inner thermoplastic resin layer is laminated with PET or PBT.

The body member blank used in the barrier paper cup having water resistance according to the present invention is obtained by extrusion lamination of a thermoplastic resin layer (40) on the outer surface of the paper base (1) and polyethylene terephthalate or polybutylene terephthalate (50) on the inner surface. A thermoplastic resin layer (41) is laminated.
In this example, the thermoplastic resin layer (41) is composed of the outermost sealant layer (41a) and the gas barrier layer (2a), and prevents the penetration of oxygen and water vapor from the outside to enhance the storage stability of the contents. In this example, a vapor deposition film provided with a vapor deposition layer (41b) is used as the gas barrier layer (2a).
The order of stacking the gas barrier layer and the vapor deposition layer is not particularly determined. However, when the resin used for the gas barrier layer has water absorption, it is desirable to dispose the vapor deposition layer on the surface where it is desired to prevent moisture permeation.

FIG. 2 (b) shows an example of a configuration in which the outer surface thermoplastic resin layer (40) is laminated with PET or PBT in addition to the case of (a). As a result, water vapor diffusing from both sides of the paper substrate can be completely blocked.
In the following description, an example in which the thermoplastic resin layer (41) on the inner surface is laminated on a paper substrate by the extrusion lamination method of PET or PBT will be taken up, and the thermoplastic resin layer (40) on the outer surface will be PET or PBT. The case of being laminated on a paper substrate by the extrusion laminating method will be described as necessary.

  The vapor barrier layer (41b) is formed on the surface of the gas barrier layer (2a) constituting the thermoplastic resin layer (41), and at the same time, the barrier property of the resin used for the gas barrier layer is reinforced and the gas barrier layer expands and contracts during cup molding. And a barrier property for suppressing moisture permeation through a crack in the deposited film.

The paper base material (1) is not particularly limited as long as it is used as a normal cup base paper. However, the basis weight of the cup paper having printability and paper strength, excellent formability, and strong surface strength. The thing of about 100-500 g / m < ² > is used preferably.

  The sealant layer (41a) constituting the thermoplastic resin layer (41) on the inner surface of the container and the sealant layer constituting the thermoplastic resin layer (40) on the outer surface of the container are heat-sealable resins such as polyethylene resin and polypropylene resin. The polyolefin resin is usually used.

  A typical example is polypropylene resin, but when heat resistance such as retort treatment is not required, low-melting resin such as low-density polyethylene, medium-density polyethylene, high-density polyethylene, and linear low-density polyethylene should be used in combination. You can also. The film thickness of the sealant layer is usually 10 μm to 60 μm, and can be provided by a known method such as hot melt extrusion using an extruder or dry lamination.

  As the gas barrier layer (2a), a vapor-deposited layer (41b) of a metal such as aluminum or an inorganic oxide such as silica, alumina, zinc oxide, tin oxide or magnesium oxide is used as a stretched polyester resin film such as a stretched polyethylene terephthalate resin film, A vapor deposition film provided on a stretched polyamide resin film such as a stretched nylon resin film can be used.

The resin used for the gas barrier layer (2a) used in the barrier paper cup having water resistance according to the present invention has the necessary mechanical properties that do not cause defects such as scratches and pinholes due to heat and friction during use and in the process. However, in consideration of processability such as moldability and adhesion to the sealant layer, and maintenance of barrier properties when the vapor deposition layer is cracked, ethylene-vinyl alcohol with excellent retort resistance can be used. Examples thereof include a polymer (EVOH) resin, an MDX nylon (Ny) resin having excellent barrier properties, and a polyvinylidene chloride (PVDC) resin.
In particular, a PET film coated with a polyacrylic acid resin can be preferably used.

  If the thickness of the gas barrier layer (2a) is less than 6 μm, it will be difficult to ensure the required characteristics, and if it is greater than 30 μm, the workability at the time of molding will deteriorate, so the thickness will be from 6 μm to 30 μm. It is desirable that

  The thermoplastic resin layer (41) is laminated on the paper substrate (1) through PET or PBT. The thickness of the PET or PBT layer (50) is preferably in the range of 10 μm to 50 μm. When the thickness is less than 10 μm, the heat resistance may deteriorate, and when the thickness exceeds 50 μm, the moldability deteriorates.

FIG. 1 is an explanatory view simply showing a manufacturing process of a barrier paper cup having water resistance according to the present invention using the body member.
As shown in FIG. 1, one end edge (11) of the body member blank (10) provided with the notch portions (31) and (32) at the upper ends of both side edges is connected to the body member (18). The body part bonding part (15) is formed so as to overlap with the end edge (12) of the cylinder to form a cylindrical shape.
Further, the bottom member (20) is circular and has a peripheral edge portion (21) erected downward. And the outer surface of the peripheral part (21) of a bottom member (20) is joined to the lower inner surface of the said trunk | drum member (18).

  Further, the lower end edge of the body member (18) is bent inward from the outside so as to cover the peripheral edge (21) along the inner surface of the bottom-in curl mold, and joined to the inner surface of the peripheral edge (21) of the bottom member. The annular leg portion (22) is formed by crimping with a knurling or an expander, while the upper peripheral edge of the body member is wound outward one or more times to form a flange portion (16) to form a paper cup.

  Although the state after the contents are stored is not shown, when the process of sealing with a lid member is performed, sealing may be performed while the upper surface of the flange (16) is planarized by ultrasonic heating. Also in this case, adhesion failure between the paper substrate and the thermoplastic resin layer is prevented by using an extrusion laminating method of PET resin or PBT resin having a melting point higher than that of the sealant layer. The effect of the present invention that suppresses the decrease in barrier properties caused by the above is useful. Furthermore, by laminating a PET or PBT resin layer having high heat resistance and mechanical strength, obstacles due to external friction and collision can be reduced.

  Such a structure is not limited to a tapered paper cup, and the same applies to a cylindrical cup-shaped paper container. Furthermore, the basics of the structure are the same even in the case of a paper container that requires edge protection of the paper base joint portion against the penetration of moisture from the contents and the external environment.

  FIG. 3 is a cross-sectional explanatory view showing an example of a body bonding portion of a barrier paper cup having water resistance according to the present invention, (a) is a cross-sectional explanatory view of a blank which is inside the body bonding portion, (b) FIG. 4 is a cross-sectional explanatory view of a blank that is outside the body bonding portion, and (c) is a cross-sectional explanatory view of the bonding portion after bonding.

  4A and 4B are cross-sectional explanatory views showing another example of the body bonding portion. FIG. 4A is a cross-sectional explanatory view of a blank which is inside the body bonding portion. FIG. 4B is an outside of the body bonding portion. It is sectional explanatory drawing of the blank used as (c), and is sectional explanatory drawing of the bonding part after bonding.

  In the trunk member blank (10) of the example shown in FIG. 3, one end edge (11) located on the inner surface side of the container in the trunk portion bonding portion (15) is thermoplastic on the inner surface side of the paper substrate (1). The resin part (4a) in which the resin layer (40) and the thermoplastic resin layer (41) on the outer surface side of the paper base (1) extend outward from the side edge of the paper base (1) It is set as the structure provided with the folding | returning resin part (4b) folded back on the outer surface side of the paper base material (1) in the vicinity of the material (1).

Further, the other edge (12) located on the outer surface side of the container in the body portion bonding portion (15) includes a thermoplastic resin layer (40) on the inner surface side of the paper substrate (1) and a gas barrier layer (not shown). The resin part (4c) in which the thermoplastic resin layer (41) on the outer surface side of the paper base material (1) laminated on the outside extends from the side edge of the paper base material (1) It is set as the structure provided with the folding | returning resin part (4d) folded by the outer surface side of the paper base material (1) in the vicinity of 1).
Thus, the resin part (4b) can secure the amount of resin in the body bonding part (15) by having the resin part (4a) folded back to the outer surface side of the paper substrate (1). The sealing property of the inner surface of the bonded portion is improved.

Moreover, the resin part (4d) can ensure the resin amount in a trunk | drum bonding part (15) by setting it as the structure which turned the resin part (4c) in the outer surface side of the paper base material (1), and bonded together. The sealability of the outer surface of the part is improved. The end portion of the resin portion (4a) and the end portion of the resin portion (4c) may be a gap or may overlap.
Or although not shown in figure, the resin part (4d) can also be set as the structure which turned up the resin part (4c) to the inner surface side of the base material (1).

  Furthermore, depending on the degree of necessity of edge protection to the outside of the body bonding portion, as shown in FIG. 4, the other end of the paper substrate located on the outer surface side of the container in the body bonding portion (15). The edge (12) has a thermoplastic resin layer (40) on the inner side of the paper base and a thermoplastic resin layer (41) on the outer side of the paper base extending outward from the side edge of the paper base (1). It is also possible to adopt a configuration in which the resin part (4c) taken out is overlapped and pressure-bonded with the thermoplastic resin (41) on the outer surface side of the paper base (1) on the inner surface side of the container.

  In the barrier paper cup having water resistance according to the present invention having such a structure, the end surface of the paper base material located inside the body bonding portion (15) is protected by the folded resin portion (4b). Since the end surface of the paper base located outside the body bonding portion (15) is protected by the folded resin portion (4d) or the resin portion (4c) sealed by thermocompression bonding, Not only does the filled content not permeate from the end face of the paper base material, but also an edge protection effect that prevents permeation from the outside of the container can be obtained.

Thus, by providing the thermoplastic resin layers (40) and (41) on both sides of the paper substrate, the resin portions (4a) and (4c) extending outward from the end surface of the paper substrate become the thermoplastic resins on both sides. The layers (40) and (41) are formed in an integrated state at the outer edge.
And the said resin part (4a) is set as the structure of the folding | returning resin part (4b) folded back to the outer surface side of a paper base material instead of the structure extended outward from the edge of a paper base material as mentioned above. In addition, the resin part (4c) extends outward from the edge of the paper base and is thermocompression bonded, or the folded resin part (4d) is folded back to the outer or inner surface of the paper base. And

  Thus, by setting the bonding resin portion of the barrel member on the inner surface side of the container to the configuration of the folded resin portion (4b) that is folded back to the outer surface side or the inner surface side of the base material, the level difference of the barrel bonding portion is The folded resin portion (4b) can be buried and have no step, and the paper substrate (1) and the end surface of the resin portion can be configured not to be exposed inside the paper cup.

In addition, by forming the resin part (4c) outwardly extending from the edge of the paper base and thermocompression bonding, the step of the body part bonding part is filled with the outer resin part (4c). Moreover, it can be set as the structure without a level | step difference, and can be set as the structure which a paper base material (1) does not expose to a paper cup exterior.
Further, by forming the resin part (4c) as a folded resin part (4d) that is folded back from the edge of the paper base to the outer surface side of the paper base, the step of the body laminating part is the folded back. The resin portion (4d) is filled with a step and there is no step, and the paper base (1) and the end surface of the resin portion are not exposed to the outside of the paper cup.

  The barrier paper cup having water resistance according to the present invention is usually provided with a flange portion (16), and at the upper end of the laminating portion (15) of the body member (18), notch portions ( 31) When the body member blank (10) provided with (32) is used, when the upper peripheral edge of the body member is wound outward one or more times to form at least a triple-structured flange portion, In addition, the base material is in a wrap-up state with the same triple structure as the portion other than the bonded portion.

  Here, even if the upper surface of the flange portion (16) having at least a triple structure is flattened by making the shape of the notches (31) and (32) different, the bonded portion is formed on the upper surface of the flange portion. The level difference that occurs at the position of can be eliminated.

In the barrier paper cup having water resistance according to the present invention, the thermoplastic resin layer is a layer including a vapor deposition layer disposed inside the gas barrier layer. By adopting such a configuration, the surface and end face of the paper substrate (1) are also protected by the gas barrier layer and the vapor deposition layer, and the gas barrier layer on the end face is cracked by folding the resin portion as illustrated in FIG. Even when it enters, it can maintain the water-blocking property, so that it is possible to obtain a paper cup having excellent barrier properties with little deterioration of the paper base material due to moisture intrusion.

  Moreover, the end surface of the gas barrier layer (2a) is not exposed to the inside of the cup by configuring the resin portion (4b) by folding the resin portion (4a) including the gas barrier layer (2a) and the vapor deposition layer (41b). It becomes a structure, can prevent a content from contacting a gas barrier layer, and does not exert a bad influence on preservation | save of a content.

  In this way, the folded resin portions (4b) and (4d) are configured such that the tip of the resin portion is folded back to the bonded portion inner base material outer surface side or the bonded portion outer base material outer surface side or inner surface side. Even when the thermoplastic resin layer includes a gas barrier layer and a protective resin layer made of different materials, when the body portion is formed, a certain amount of resin for bonding is formed in the body portion bonding portion (15). In addition to protecting the end face of the paper base material (1), the step due to the paper base material of the body part bonding portion (15) can be eliminated. At the same time, even when the folded resin portion is folded, cracking of the deposited film of the gas barrier layer (2a) may occur due to the expansion and contraction of the resin portion, so that the barrier property can be prevented from lowering the water shielding property.

  In particular, the resin part (4c) formed of the thermoplastic resin layers (40) (41) on both sides at the end of the paper base (1) bonded to the outside of the body part bonding part (15) Resin (4b) or thermoplastic resin formed at the end of the inner paper substrate (1) after being formed by simple thermocompression, unless there is an additional need to prevent the entry of moisture etc. from Adhering to the layer (41) and fixing it makes it possible to protect the required end, secure a certain amount of resin at the bonded part, and eliminate the level difference in the body part bonding part (15) when the body part is formed. You can also

Further, even when the thermoplastic resin layer (40) includes a gas barrier layer (2a) made of a material that easily corrodes, such as a metal or its oxide, the resin portion at the end of the paper substrate is folded back. As a result, the end face of the gas barrier layer (2a) is not exposed to the inside of the container, the contents can be prevented from coming into contact with the gas barrier layer, and the storage of the contents is not adversely affected. .
In addition, the constituent elements of the thermoplastic resin layer are not limited to the sealant layer, the gas barrier layer, and the protective resin layer, but an intermediate layer such as a film for reinforcing mechanical strength or for promoting adhesion between layers. An intermediate layer such as a primer coat or a corona treatment may be formed on the inner surface side.

  Such a structure is not limited to a tapered paper cup, and may be a cylindrical or rectangular cup-shaped paper container, and requires edge protection of the paper base material and mechanical durability of the surface. It can be used for paper containers.

  The water-resistant barrier paper cup of the present invention can be decorated by a known method. For example, a paper cup can be manufactured by using a base material provided with a decorative layer as a body blank by printing such as normal gravure or offset on the surface of a paper base material. Alternatively, the surface of the body portion of the molded paper cup can be covered with a plastic film provided with a decorative layer by printing or metal vapor deposition.

<Example 1>
A paper base material (basis weight 260 g / m ² ) was punched out, and long windows were formed in the outer part of both the edges of the region to be the body member blank including the edges.
A polypropylene resin layer (20 μm) is attached to one side of a paper substrate by a dry lamination method, and the other layer is a laminate consisting of an alumina vapor deposition layer / ethylene-vinyl alcohol copolymer layer (12 μm) / polypropylene resin layer (20 μm). The film was stuck by an extrusion laminating method of polybutylene terephthalate resin (20 μm) so that the alumina vapor deposition layer surface and the paper base material layer were in contact with each other, thereby preparing a laminated sheet in which the inner surfaces were joined and integrated at the position of the long window.

  Then, a triangular notch with a width of 9 mm and a height of 5 mm is formed on the upper side edge of one side of the paper base material, and a triangular notch with a width of 8 mm and a height of 6 mm is formed on the other side edge. A body blank was formed by punching into a sector shape having a part (upper side length 225 mm, lower side length 162 mm). In addition, the resin part provided in both the side edge edges was provided with a width of 5 mm, and a body blank having a folded resin part extending 2.5 mm was formed.

The side edges of the blank having the folded resin portion were overlapped and joined and integrated, and a barrel portion was provided to form a barrel portion.
Next, the outer surface of the peripheral part of the bottom member which has a circular-shaped peripheral part standing upright was joined to the lower inner surface of the trunk part. The layer structure used for the bottom member was the same as that of the body blank.

  Using a cup molding machine, after joining the outer surface of the peripheral portion of the bottom member to the lower inner surface of the barrel member, and further covering the peripheral portion along the inner surface of the bottom incurl mold, An annular leg having a diameter of 52 mm was formed by bending the lower end edge inward from the outside, bonding it to the inner surface of the peripheral edge of the bottom member, and crimping with a knurling. At this time, no scratches or blisters were seen on the cup surface including the outer surface of the lower end edge of the barrel member.

  In addition, the top curl unit forms a paper cup with an opening diameter of 69 mm, having a flange portion with a width of 3 mm, with the upper half wound around the upper half, the lower half is single wound and the upper half is double wound. did.

This paper cup was molded without a step in the portion located on the body bonding portion on the upper surface of the body bonding portion and the flange portion. Further, using an ultrasonic sealing device, pressure was pressed from above and below, and the upper surface of the flange was flattened.
The paper cup was formed without a step at a portion located on the body bonding portion on the upper surface of the flange portion, although the upper surface of the flange portion was flattened.

<Example 2>
As in Example 1, except that a polypropylene resin layer was attached to one side of a paper base (having a basis weight of 260 g / m ² ) on which a long window was formed, by using an extrusion lamination method of polybutylene terephthalate resin (20 μm). A paper cup was formed.

This paper cup was molded without a step in the portion located on the body bonding portion on the upper surface of the body bonding portion and the flange portion. Further, using an ultrasonic sealing device, pressure was pressed from above and below, and the upper surface of the flange was flattened.
The paper cup was formed without a step at a portion located on the body bonding portion on the upper surface of the flange portion, although the upper surface of the flange portion was flattened.
Furthermore, water was added as a content and sealed with a lid, and then boiled in hot water for 30 minutes.

<Example 3>
Instead of sticking a polypropylene resin layer on one side of a paper substrate (basis weight 260 g / m ² ) on which a long window is formed, a laminated film of a polypropylene resin layer (30 μm) and a polyethylene terephthalate resin (12 μm) is extruded and laminated A paper cup was formed in the same manner as in Example 2 except that the sticking was performed.

This paper cup was molded without a step in the portion located on the body bonding portion on the upper surface of the body bonding portion and the flange portion. Further, using an ultrasonic sealing device, pressure was pressed from above and below, and the upper surface of the flange was flattened.
The paper cup was formed without a step at a portion located on the body bonding portion on the upper surface of the flange portion, although the upper surface of the flange portion was flattened.
Furthermore, water was added as a content and sealed with a lid, and then boiled in hot water for 30 minutes.

<Comparative Example 1>
As in Example 1, except that a polypropylene resin layer was attached to one side of a paper base (having a basis weight of 260 g / m ² ) on which a long window was formed, it was attached by an extrusion laminating method of polyethylene resin (20 μm). A paper cup was molded.
In this paper cup, blistering due to delamination of the laminated body was observed at a part of the body bonding portion.

  As described above, according to the present invention, the adhesive or the adhesive layer is softened by the heat at the time of cup molding, and the water vapor contained in the paper substrate is vaporized between the paper substrate and the film. It was possible to provide a paper cup capable of being subjected to hot water retort treatment that can prevent the phenomenon of peeling and maintain barrier properties including water shielding of not only the paper end face of the substrate but also the paper surface coating.

DESCRIPTION OF SYMBOLS 1 ... Paper substrate 2a ... Gas barrier layer 3 ... Laminated sheet 40 ... Thermoplastic resin layer 40b ... Protective resin layer 41 ... Thermoplastic resin layer 41a ... Sealant layer (PP)
41b ··· Vapor deposition layer 4 ··· Resin portion 4a · ··· Extended resin portion 4b ··· Folded resin portion 4c · · · Outbound resin portion 4d · · · Folded resin portion 10 · · · Body member blank 11 · · · Side end having resin portion Edge 12 ... Side edge 13 with resin part ... Long window 14 ... Long window 15 ... Laminated part 16 ... Flange part 18 ... Body member (side material)
19 ... Lower end of body member 20 ... Bottom member (bottom material)
21 Peripheral part (standing part)
22 ... Ring leg 31 ... Notch 32 ... Notch

Claims (8)

A method for producing a paper cup having a body laminating portion in which one side edge of a blank composed of a laminated sheet provided with a thermoplastic resin layer on the inner surface and outer surface of a paper base material is superimposed on the other side edge. in a thermoplastic resin layer provided on at least the inner surface, a method of forming a body portion by laminating a paper substrate via a polyethylene terephthalate or polybutylene terephthalate, which is provided by extrusion lamination,
A method for producing a barrier paper cup having water resistance , wherein the thermoplastic resin layer provided on the inner surface includes a sealant layer, and the polyethylene terephthalate or polybutylene terephthalate has a higher melting point than the sealant layer . Barrier having waterproof according to claim 1, characterized in that the thermoplastic resin layer provided on the outer surface is laminated to a paper substrate via a polyethylene terephthalate or polybutylene terephthalate, which is provided by extrusion lamination Paper cup manufacturing method. The method for producing a barrier paper cup having water resistance according to claim 1, wherein the thermoplastic resin layer on the inner surface includes a gas barrier layer . The gas barrier layer comprises an ethylene-vinyl alcohol copolymer, MDX nylon, a polyvinylidene chloride film, a polyethylene terephthalate film coated with a polyacrylic acid resin, or a film obtained by depositing a metal, a metal oxide, or an inorganic oxide thereon. The method for producing a barrier paper cup having water resistance according to claim 3. The side edge located inside the body bonding part of the blank has a folded resin part that is folded back from the side edge of the paper base material to the outer surface side of the base material, The side edge located on the outer side of the body part bonding part of the blank has a resin part extending from the side edge of the paper base material, according to any one of claims 1 to 4. For producing a barrier paper cup having water resistance of 5% . The resin part extending from the side edge located outside the body part bonding part of the blank has a folded resin part that is folded back to the outer surface side or the inner surface side of the paper base material. A method for producing a water-resistant barrier paper cup as described in 1. Resin portion extending from a side edge located outside of the body portion bonding portion of the blank, characterized in that in close contact along the inside of the blank of the body portion bonding portion, claim 5 Or the manufacturing method of the barrier paper cup which has water resistance of 6 . 8. The water resistance according to claim 5 , wherein the resin portion extending from the side edge located on the inner side and / or the outer side is provided over the entire length of the side edge. 9. A method for producing a barrier paper cup having

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