JP5779898B2 - Paper cup with barrier and heat resistance - Google Patents

Description

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

  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 joint 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.

  In order to ensure the barrier property of the joint portion of the paper cup, for example, as an end face processing (edge protection) method for protecting the end faces on both ends 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 a body member (100) made of a laminated sheet as shown in FIG. 13 (a) in which a thermoplastic resin (102) is laminated on a paper substrate (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 inside, and the paper end surface is protected with a thermoplastic resin as shown in FIG.

  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.

  A paper base material is used as an end face processing method for producing a paper cup having excellent barrier properties by protecting the end faces at both ends of the joint portion of the body member constituting the body section of the paper cup without performing skive hemming. There has been proposed a method of manufacturing a paper cup using a blank whose end face is covered by extending a water- and oil-resistant thermoplastic film covering the surface of the paper (see, for example, Patent Document 1).

In a paper cup having a barrier property that protects the end face of the paper base material, the inner edge of the body portion bonding portion is formed by extending a thermoplastic resin layer from the paper base material throughout. Thus, the film of the thermoplastic resin layer extending from the paper base material is irregularly formed during cup molding, and it is sufficient to cover the end surface of the paper base material which is the original purpose. could not. Moreover, the finish as a paper cup was bad and there existed problems, such as a malfunction produced in appearance. 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, since the flange portion is formed by winding the upper end edge of the body member into the opening, a step portion due to the thickness of the paper of the base material is generated in the flange portion. 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. A solution is also prepared in which a blank is partly cut off so that sealing can be performed reliably even if a lid material is stacked on the upper surface of the substrate 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. Retort sterilization treatment using a base paper that is formed of a laminated sheet and that has a rice basis weight of 150 to 400 g / m 2 and that has a Steecht size of 400 seconds or more. 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 penetrates into the paper base during retort sterilization, the paper base may have a very high dry strength, wet strength, and hot water resistance, which may cause a swell phenomenon. In addition, the container does not deform due to a decrease in rigidity.
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 step of curling top side and bottom side ends of a side material inside a container when forming a portion that has a top material, a side material, and a bottom material and bonds the side material and the top material. Has proposed 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 for one or more rounds. This is a container that reliably seals the end surface of the body side material of the body to prevent permeation of hot water or the like from the end surface.

As described above, in order to enhance the barrier property of the liquid paper container until it can withstand the hot water retort treatment, many proposals for preventing moisture penetration from the end face of the paper base material have made it difficult to achieve The issue of ensuring water resistance is making some progress.
However, the thermoplastic resin layer provided on the surface of the paper base material is required to have both a barrier property of water resistance and oil resistance and a sealant property of heat sealability at the time of molding. The problem pointed out in Patent Document 1 that tends to be neglected has not been solved yet.

  Of the problems caused by insufficient mechanical strength of the thermoplastic resin layer provided on the surface of the paper base material, the serious problem is surface scratches caused by molding damage, such as pinholes and cracks generated The necessary barrier properties are lost due to the pores, and it becomes impossible to withstand the hot water retort process, which is particularly severe in terms of hot water and pressure.

  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, A cup-shaped paper container has been proposed (Japanese Patent Application No. 2010-051476) that prevents the occurrence of flaws and has a resistance to hot water permeation, and that can maintain a barrier property that allows hot water retort treatment.

  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) for improving the adhesion of the sealant layer while maintaining the moldability of the paper.

  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).

  By providing a heat-resistant and wear-resistant resin layer on the cup body by the dry laminating method, the adhesion to the sealant layer is improved while maintaining the moldability during cup molding. Several solutions for improving resistance have been shown, 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 property that the vapor deposition thickness is thin, and in the molding process as described above, it is easy to break and open a hole. It is not easy to ensure barrier properties.

An example of the above problem in the process of forming the container bottom will be specifically described with reference to FIGS.
Normally, when molding the bottom of a paper cup, both sides of a fan-shaped body member (side material) are overlapped and bonded to form a cone, and the outer periphery of a circular bottom member (bottom material) is raised on this bottom. An annular leg portion is formed by fitting an object.

In FIG. 11 (a), a body member (18) formed in a conical shape by adhering both ends is fitted into a die (C1) on a truncated cone with its lower end (19) facing upward, In addition, a state where the bottom member (20) with the upright portion (21) on the upper side is placed on the mold (C1) is schematically shown in a cross-sectional view.
Next, FIG. 11B shows a bottom incurling state in which the lower end portion (19) of the body member is curled inward so as to sandwich the rising portion of the bottom member.

  Here, since the inner side of the bottom incurl mold (C2) is in pressure contact with the outer side of the lower end portion of the body member in order to bend the lower end portion (19) of the body member from the upper part of the outer side to the inner side of the standing member. Often, a layer having a function of securing a barrier property such as a metal or inorganic compound vapor deposition layer contained in a thermoplastic resin layer outside the container of the barrel member is damaged or stretched to cause a crack, or it will break significantly. Happens.

A typical example of the crimping of the next annular leg portion of the bottom incurl is shown in FIG.
As a method of pressing the lower end portion (19) of the body member curled inward from the inner side of the annular leg portion to the standing portion of the bottom member, as shown in FIG. Inserting a rotating roller (knurl) and crimping while rotating the knurling (C3), or expanding the expansion member (C4) into the annular leg instead of the knurling as shown in (b) Can be crimped with.

  Also in this case, since the outer surface of the container at the lower end portion (19) of the trunk member is in pressure contact with the knurling or expansion member, the metal or inorganic compound deposition layer contained in the thermoplastic resin layer outside the container of the trunk member, etc. The layer having the function of securing the barrier property is damaged or stretched to cause a crack, or it may break considerably.

  In the step of forming the top curl of the paper cup and the step of forming the top flange by ultrasonic pressure bonding, when the contact between the outer surface of the container and the pressure bonding mold occurs, the thermoplastic resin of the barrel member is similarly caused by friction. A layer having a function of ensuring a barrier property such as a metal or an inorganic compound vapor deposition layer contained in the layer is damaged or stretched to cause a crack or breakage.

  Thus, 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 molding process of the paper cup. A similar problem may occur in the step of bending the layer (see FIG. 10).

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. The present invention has been made in view of the above problems, and it is an object to provide a hot water retortable paper cup that can maintain barrier properties including water shielding of the paper surface as well as the paper end surface of the substrate. And

The present invention provides a protective layer made of a resin layer having excellent barrier properties, which is laminated on the outer surface of a base material of a body member of a paper cup, on the paper base side of a gas barrier layer made of a metal or inorganic compound vapor-deposited plastic film. Even when cracks are formed in the vapor deposition film of the gas barrier layer when molding containers such as top curls and bottom curls, it is possible to block moisture penetrating from the cracks. It is a paper cup that prevents the occurrence of flaws and has a high resistance to the penetration of hot water, and can maintain the water resistance that allows hot water retort treatment.

According to the first aspect of the present invention, one side edge of a blank composed of a paper-based laminated sheet having thermoplastic resin layers provided on the inner surface and the outer surface is used as the other side edge. In a paper cup having an overlapped body bonding part, the thermoplastic resin layer provided on the outer surface side of the paper base is a gas barrier layer made of a metal or inorganic compound vapor-deposited plastic film, and the paper base side of the gas barrier layer. it is a paper cup, characterized in that includes a provided an ethylene-vinyl alcohol copolymer or Ranaru protective resin layer.

The invention according to claim 2 of the present invention is characterized in that a protective resin layer contained in the thermoplastic resin layer provided on the outer surface side is provided on the paper substrate side surface of the gas barrier layer. 1. A paper cup according to 1.

  According to the invention of claim 3 of the present invention, a thermoplastic resin layer including a gas barrier layer provided with a protective resin layer is laminated on a paper substrate through a laminated film whose surface side is polypropylene resin by extrusion lamination of polypropylene resin. The paper cup according to claim 2.

The invention of claim 4 of the present invention is characterized in that a protective resin layer contained in the thermoplastic resin layer provided on the outer surface side is provided on the surface of the paper base on the gas barrier layer side. 1. A paper cup according to 1.

The invention according to claim 5 of the present invention is such that the side edge located inside the overlapping portion of the blank is folded back to the outer surface side of the substrate, the resin portion extending from the side edge of the paper substrate. has a folded resin portion, the side edges located outside the overlapping portion of the blank is characterized by having a resin portion extending from a side edge of said paper substrate, of claims 1-4 It is a paper cup of any one of these.

According to a sixth aspect of the present invention, the resin portion extending from the side edge located outside the overlapping portion of the blank has a folded resin portion that is folded back to the outer surface side or the inner surface side of the paper substrate. A paper cup according to any one of claims 1 to 5 , characterized in that

The invention according to claim 7 of the present invention is characterized in that a resin portion extending from a side edge located outside the overlapping portion of the blank is pressure-bonded to the blank inside the overlapping portion. The paper cup according to any one of claims 1 to 5.

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 edges, of claims 1 to 7 It is a paper cup of any one of these.

According to the invention of claim 1 of the present invention, one side edge of a blank composed of a paper-based laminated sheet provided with a thermoplastic resin layer on the inner surface and the outer surface is set on the other side. In a paper cup having a body bonding part overlapped on the edge, the thermoplastic resin layer provided on one side is provided on the paper base side of the gas barrier layer made of a metal or inorganic compound vapor-deposited plastic film and on the paper base side. Friction from the outside during storage and transportation by including a protective resin layer made of any of ethylene-vinyl alcohol copolymer (EVOH), nylon (Ny), and polyvinylidene chloride (PVDC) And a paper cup with excellent durability against impact.

  Not only when the bottom of the curl mold is in pressure contact with the outside of the lower end of the barrel member during molding of the bottom of the container, but also when the gas barrier layer is cracked or when the annular leg is crimped Even when the outer surface of the lower end and the knurl or expansion member are in pressure contact with each other, the barrier property is deteriorated due to damage such as cracks in the gas barrier layer. It is possible to prevent the penetration of hot water into the paper base material layer due to the above. The same prevention effect can be expected when molding the top of the paper cup.

  According to the invention according to claim 2 of the present invention, the protective resin layer contained in the thermoplastic resin layer provided on the one surface is provided on the paper substrate side surface of the gas barrier layer, so that the molding process is in progress. Thus, the stress applied to the gas barrier layer is relieved to prevent the occurrence of cracks across the entire surface of the gas barrier layer. At the same time, the penetration of moisture and the like from the cracks generated at that time is stopped at the position closest to the cracks, so that it is possible to effectively prevent the deterioration of the paper base material due to the intrusion into the paper.

  According to the invention of claim 3 of the present invention, the thermoplastic resin layer including the gas barrier layer provided with the protective resin layer is formed on the paper base material through the laminated film whose surface side is polypropylene resin by extrusion lamination of polypropylene resin. By being laminated, when melted on the paper base layer by the extrusion laminating method, it effectively avoids the following problems caused by hot pressure for lamination at the time of manufacture, and heat meltability as a sealant layer And polypropylene resin having necessary heat resistance can be used effectively.

  When the extrusion laminating method is used as a method of laminating a protective resin layer on the base paper, a resin having a melting point lower than the melting point of the resin (for example, polypropylene resin) used for the outer sealant layer (for example, polyethylene resin) Needs to be melted between the substrate and, for example, a polyethylene terephthalate layer to form a 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 polyethylene resin with a low melting point between the paper substrate and the polyethylene terephthalate layer is melted and foamed by evaporation of moisture generated from the heated paper substrate, an air layer is formed, and the floated thermoplastic resin layer becomes strong. It happens that a hole such as a pinhole that is heated and breaks the sealing property is likely to be generated.

In order to prevent the occurrence of defects as described above in the bonding at the time of cup molding, as a layer structure of a thermoplastic resin layer including a protective resin layer and a paper base layer, use an extrusion lamination method of polypropylene resin for adhesion. Is useful.
However, since the polypropylene resin has poor adhesion to the paper substrate as it is, it is desirable to laminate the polypropylene resin via a polyethylene terephthalate film or the like that has been dry laminated on the paper substrate surface in advance.

According to the invention according to claim 4 of the present invention, the protective resin layer contained in the thermoplastic resin layer provided on the one surface is provided on the gas barrier layer side surface of the paper base material, and thereby the extrusion laminating method. Thus, it is possible to effectively avoid the above-mentioned problems caused by the heat pressure for the lamination at the time of production in the case of being laminated on the paper base material layer.

In order to prevent the occurrence of defects as described above in laminating at the time of cup molding, a dry laminating method using an isocyanate-based adhesive is adopted as a method of laminating the protective resin layer and the paper base material layer. It is useful. In the dry laminating method using an isocyanate-based adhesive, the cured adhesive layer after lamination is in a state that does not substantially heat melt. Can be prevented.
As a result, it becomes possible to ensure the barrier property and prevent the penetration of hot water into the paper base material layer due to scratches or pinholes in the thermoplastic resin layer.
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 of claim 5 of the present invention, the nylon resin used in the protective resin layer is polymetaxylylene adipamide, which is caused by ensuring barrier properties and scratches or pinholes in the thermoplastic resin layer. Further prevention of penetration of hot water into the paper substrate layer is further ensured.
Examples of the protective resin layer include ethylene-vinyl alcohol copolymer (EVOH) having excellent retort resistance, nylon (Ny) having excellent barrier properties, and polyvinylidene chloride (PVDC). Although it can be used, a stretched film of MXD6 (polymetaxylylene adipamide) having an excellent barrier property among nylon resins is particularly desirable.

  According to the invention according to claim 6 of the present invention, the side edge located inside the overlapping portion of the blank has the resin portion extending from the side edge of the paper base as the outer surface of the paper base. The side edge located outside the overlapped portion of the blank has a resin portion extending from the side edge of the paper base, so that in the bonded portion In the state where the outer surface side base material end face is overlapped, a stepped portion is generated in the body bonded portion, which is inconvenient in appearance, and also has a problem that moisture permeation from outside tends to occur due to wrinkles at the time of overlapping. Can be eliminated.

  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 overlap part of the said blank is the folding | returning resin part which turned up the outer surface side or inner surface side of the paper base material 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.

  According to the invention which concerns on Claim 8 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 but also ensures the amount of resin in the body bonded portion.

  According to the invention which concerns on Claim 9 of this invention, the resin part extended from the side edge located in the said inner side and / or the outer side is provided in the full length of a side edge, and body parts other than a flange part are bonded together. A paper cup with excellent sealing performance of the part is obtained.

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 protective resin layer is formed on the gas barrier layer surface, and (b) shows a configuration in which the protective resin layer is formed on the paper substrate surface. 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 1st punching process which provides the long window of the trunk | drum member blank used for manufacture of a paper cup is shown, (a) is plane explanatory drawing, (b) is the A-A 'sectional explanatory drawing of (a). The thermoplastic resin bonding process of the trunk | body member blank used for manufacture of a paper cup is shown, (a) is plane explanatory drawing, (b) is the A-A 'line cross-sectional explanatory drawing of (a). 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. The thermoplastic resin bonding process of the trunk | body member blank used for manufacture of a paper cup is shown, (a) is plane explanatory drawing, (b) is the A-A 'line cross-sectional explanatory drawing of (a). 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 at the time of bottom part shaping | molding. (A) Bottom material placement (b) shows the process of bottom incurl. It is sectional explanatory drawing at the time of bottom part shaping | molding. (A) shows knurls (b) shows examples of caulking with an expander. It is sectional explanatory drawing which shows the example of a skive hemming process.

Embodiments of a paper cup having barrier properties and heat resistance according to the present invention will be described in detail below with reference to the drawings as necessary.
A simple cross-sectional explanatory diagram of the body member blank of the paper cup of the present invention is shown in FIG. Parts that are not directly related to the explanation are omitted.

  The paper cup of the present invention has a body portion in which one side edge is overlapped with the other side edge of a blank having a thermoplastic resin layer provided on the inner surface and the outer surface, which is composed of a paper-based laminated sheet. In a paper cup having a bonded portion, the thermoplastic resin layer provided on one side includes a gas barrier layer made of a metal or inorganic compound vapor-deposited plastic film, and a protective resin layer provided on the paper substrate side of the gas barrier layer. It is a paper cup.

  As shown in FIG. 2 (a), the protective resin layer is disposed on the inner surface of the gas barrier layer constituting the thermoplastic resin layer (the surface on the paper substrate side), thereby protecting the surface of the gas barrier layer. At the same time, it has a barrier property for suppressing moisture permeation through a crack in the deposited film due to expansion and contraction of the gas barrier layer during cup molding.

Moreover, this protective resin layer may be arrange | positioned on the surface of the paper base material by the side of a gas barrier layer, as shown in FIG.2 (b). In this case, there is a possibility that the effect of the extended resin part on both sides of the body member blank may be suppressed, but the stability at the time of cup molding is achieved by laminating the protective resin layer with the paper base material by dry lamination. There is an effect of improving.
In the following description, an example in which the protective resin layer is disposed on the surface of the paper base material will be mainly described, and the case where the protective resin layer is disposed on the surface of the gas barrier layer will be described as necessary.

The paper base layer (1) is not particularly limited as long as it is used as a normal cup base paper. However, the paper base layer (1) has printability and paper strength, excellent formability, and strong surface strength. An amount of about 100 to 500 g / m ² is preferably used.

  The sealant layer constituting the thermoplastic resin layer (41) on the outer side of the container and the sealant layer constituting the thermoplastic resin layer (40) on the inner side of the container are heat-sealable resins, for example, polyolefin resins such as polyethylene resins and polypropylene resins 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 of a metal such as aluminum or an inorganic oxide such as silica, alumina, zinc oxide, tin oxide, magnesium oxide, or the like, a stretched polyester resin film such as a stretched polyethylene terephthalate resin film, or stretched nylon A vapor deposition film provided on a stretched polyamide resin film such as a resin film can be used.

As the protective resin layer (41b) used for the paper cup of the present invention, a material having necessary mechanical properties that does not cause defects such as scratches and pinholes due to heat and friction during use and in the process can be used. However, in consideration of processability such as moldability and adhesion to the sealant layer, and maintenance of barrier properties when the vapor deposition layer cracks, an ethylene-vinyl alcohol copolymer (EVOH) resin having excellent retort resistance, Examples thereof include nylon (Ny) resin and polyvinylidene chloride (PVDC) resin having excellent barrier properties.
Among nylon resins, a stretched film of MXD6 (polymetaxylylene adipamide) resin having excellent barrier properties is optimal.
If the thickness of the protective resin layer (41b) 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. The following is desirable.

  The protective resin layer (41b) and the paper base layer (1) can be bonded by a normal dry laminating method using an isocyanate-based adhesive, and the adhesive layer melts by heating after the adhesive is crosslinked and cured. There is nothing. The constituent component of the isocyanate-based adhesive can be appropriately selected in consideration of the adhesiveness between the protective resin layer (41b) and the paper substrate layer (1).

FIG. 1 is an explanatory view simply showing the manufacturing process of the paper cup of the present invention.
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. In this case as well, the effect of the present invention that suppresses a decrease in barrier properties caused by cracks in the deposited layer by the protective resin layer is useful.

  Such a structure is not limited to a tapered paper cup, and the same applies to a cylindrical cup-shaped paper container. Furthermore, 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, the basic structure of the following joint portion is the same.

  As shown in FIG. 2, the paper cup of the present invention has an ethylene-vinyl alcohol copolymer (EVOH) resin layer excellent in retort resistance and a barrier property between the paper base layer (1) and the gas barrier layer (2a). Since one of the excellent nylon (Ny) resin layer and polyvinylidene chloride (PVDC) resin layer is formed, cracks occur in the vapor deposition layer of the gas barrier layer (2a) in the cup molding process. Thus, it is possible to make a container having excellent resistance against a decrease in barrier properties.

  Further, as described with reference to FIGS. 11 and 12, this occurs because the inside of the bottom incurl mold (C2) is in pressure contact with the outside of the lower end portion (19) of the paper cup when molding the bottom of the paper cup. When the thermoplastic resin layer is damaged or cracked, the barrier property is reduced, and when the annular leg (22) is crimped, the outer surface of the lower end (19) of the barrel member and the knurling (C3) or expansion (C4) member are Prevents the deterioration of the barrier properties due to scratches and cracks in the thermoplastic resin layer caused by pressure contact, ensuring the barrier properties and effectively penetrating hot water due to scratches and pinholes in the thermoplastic resin layer It becomes possible to prevent.

  3A and 3B are cross-sectional explanatory views showing an example of the body bonding portion of the paper cup of the present invention, in which FIG. 3A is a cross-sectional explanatory view of a blank inside the body bonding portion, and FIG. It is sectional explanatory drawing of the blank used as the outer side of a part, (c) is sectional explanatory drawing of the bonding part 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).

Moreover, the other edge (12) located in the container outer surface side in the trunk | drum bonding part (15) is the thermoplastic resin layer (40) of a paper base material (1) inner surface side, and a protective resin layer (FIG. Resin in which the thermoplastic resin layer (41) on the outer surface side of the paper base material (1) laminated with a gas barrier layer (not shown) extends outward from the side edge of the paper base material (1). The part (4c) is provided with a folded resin part (4d) which is folded back on the outer surface side of the paper base material (1) in the vicinity of the base material (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 paper cup of the present invention having such a structure, the end surface of the paper base material positioned inside the body portion bonding portion (15) is protected by the folded resin portion (4b). Since the end face of the paper base located outside the mating part (15) is protected by the folded resin part (4d) or the resin part (4c) sealed by thermocompression bonding, the contents filled in the container Not only does 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.

Furthermore, by providing the thermoplastic resin layers (40) and (41) on both sides of the paper substrate, and in particular by providing a protective resin layer between the thermoplastic resin layer on the outer surface and the paper substrate layer, The penetration of water from the surface pinholes, cracks, etc. of the gas barrier layer (2b) to the material (1) can be effectively prevented.
The protective resin layer provided between the thermoplastic resin layer and the paper base material layer may be provided between the thermoplastic resin layer on the inner surface and the paper base material layer as necessary, and moisture intrusion from cracks may occur. Ideally placed on the side of concern.

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 paper cup of 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), notches (31) (32) are formed on the upper edges of both sides. By using the body member blank (10) provided with the body member, when the upper peripheral edge of the body member is wound outward one or more times to form a flange portion having at least a triple structure, the base material is also formed in the bonded portion. Then, the wrapping state of the triple structure is the same as the portion other than the bonding 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 paper cup of the present invention, the thermoplastic resin layer is configured as a layer including a protective resin layer disposed inside the gas barrier layer. By adopting such a configuration, the surface and end surface of the paper substrate (1) are also protected by the gas barrier layer and the protective resin layer, and the gas barrier layer on the end surface is cracked by folding the resin portion as illustrated in FIG. Even when water enters, it is possible to maintain a water-blocking property, so that a paper cup excellent in barrier properties with little deterioration of the paper base material due to moisture intrusion can be obtained.

  Moreover, the end surface of the gas barrier layer (2a) is 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 protective resin layer (40b). It is possible to prevent the contents from coming into contact with the gas barrier layer without adversely affecting the preservation of the contents.

  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 if the thermoplastic resin layer (40) includes a gas barrier layer (2a) and a protective resin layer (40b) of different materials, when the barrel portion is formed, the thermoplastic resin layer (40) is pasted at the trunk portion bonding portion (15). A certain amount of resin for alignment can be secured, and not only the end face of the paper substrate (1) can be protected, but also the level difference due to the paper substrate of the body portion bonding portion (15) can be eliminated. At the same time, the protective resin layer (40b) having a high barrier property prevents a decrease in water shielding even if the vapor deposited film of the gas barrier layer (2a) may crack due to the expansion and contraction of the resin portion when the folded resin portion is folded back. I can do it.

  Further, as shown in FIG. 2 (b), from the inner surface side of the paper base layer (1), any one of ethylene-vinyl alcohol copolymer (EVOH), nylon (Ny), and polyvinylidene chloride (PVDC). In the configuration in which the protective resin layer (40b) is laminated using an isocyanate adhesive by a dry laminating method, and the thermoplastic resin layers (40) (41) are provided on both sides of the paper substrate (1), Forming the resin parts (4a) and (4c) for sealing the end face of the paper substrate (1) by simply thermocompression bonding by integrating the inner surfaces at the tips of the thermoplastic resin layers (40) and (41). Can do.

  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.

  Next, in the case where the protective resin layer is provided on the paper substrate surface as an example of the method for producing the paper cup of the present invention (when the blank cross section is FIG. 2B), the method for producing the body member blank is included. explain.

First, a plurality of fan-shaped body member blanks (10) are arranged and printed on a roll-shaped paper substrate (1), and an ethylene-vinyl alcohol copolymer (EVOH) layer or nylon (Ny) is formed on the outer surface. A protective resin layer (41b) composed of a layer or a polyvinylidene chloride (PVDC) layer is laminated via an isocyanate adhesive by a dry laminating method to form a laminated sheet.
On both end edges (11) and (12) of the region to be the body member blank of this laminated sheet, the outer portions including the end edges are perforated as long windows (13) and (14) (see FIG. 5 (a), (b) reference) to the first punching step.

  A thermoplastic resin layer (40) such as polypropylene resin is formed on the inner surface of the laminated sheet in which the long windows (13) and (14) are formed by printing the trunk member blank (10), and metal or inorganic is formed on the outer surface. A thermoplastic resin layer (41) including a gas barrier layer made of a compound vapor-deposited plastic film is laminated by extrusion lamination to form a laminated sheet. At this time, the resin portions (4a) and (4c) in which the thermoplastic resin layer is laminated are formed on the long window portion of the paper substrate (1) (see FIGS. 6A and 6B) to heat. Plastic resin bonding process.

  Alternatively, the thermoplastic resin layer (40) is formed on the inner surface of the paper base (1) on which the long window (13), (14) is formed by printing the body member blank (10), and the outer surface is metal. Alternatively, heat including a gas barrier layer (2a) made of an inorganic compound vapor-deposited plastic film and a protective resin layer (41b) made of an ethylene-vinyl alcohol copolymer (EVOH) layer, a nylon (Ny) layer, or a polyvinylidene chloride (PVDC) layer A plastic sheet (41) is laminated to form a laminated sheet. At this time, the resin portions (4a) and (4c) are formed on the long window portion of the paper base material with the thermoplastic resin layer (see FIGS. 8A and 8B) to the thermoplastic resin bonding step. .

An unnecessary portion of the body member blank (10) in which a long window portion including the resin portions (4a) and (4c) provided to extend outward from the paper base (1) of the laminated sheet is formed. Cut continuously.
At the same time, a plurality of printed fan-shaped body member blanks (10) are punched out of the laminated sheet from which unnecessary portions have been cut out, and each body member is formed with resin portions (4a) and (4c). A blank (10) is produced (see FIGS. 7A and 7B and FIGS. 9A and 9B) to a second punching step.

The resin sections (4a) and (4c) extending outward from the paper substrate (1) by a predetermined width through these steps are formed on both side edges. FIG. 2 shows a cross section thereof. Such a trunk member blank (10) can be produced.
Forming a paper cup using this body member blank can be done by bending a resin part on which a thermoplastic resin layer is laminated and then molding it with a well-known cup molding apparatus, or by laminating a thermoplastic resin layer. This can be easily done by using a cup molding apparatus provided with a resin part bending apparatus.

  The 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 laminated film consisting of a polypropylene resin layer (20 μm) / ethylene-vinyl alcohol copolymer layer (12 μm) on one side of a paper base layer (basis weight 260 g / m ² ), an ethylene-vinyl alcohol copolymer layer surface and a paper base Punching the laminated sheet pasted by the dry laminating method using an isocyanate-based adhesive so that the material layer is in contact with both edges of the area that will be the body member blank, including the edge, on the outer part A long window was formed.

  Next, an isocyanate-based adhesive is used so that a polypropylene resin layer (30 μm) / stretched polyethylene terephthalate resin layer (12 μm) laminated film is placed on the other side of the paper base of the laminated sheet. The laminate was bonded by the dry laminating method, and the surface of the paper base material was made of a polypropylene resin layer on both sides.

Further, a laminated sheet comprising a polypropylene resin layer (30 μm) / inorganic oxide vapor deposited barrier film (12 μm) / polypropylene resin layer (30 μm) is provided on the inner surface side (ethylene-vinyl alcohol copolymer layer side) of the laminate. A polypropylene resin film (30 μm) was laminated on the side by extrusion lamination using polypropylene resin, and 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.

  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 were found 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 bonding was performed from above and below to flatten the upper surface of the flange.
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 2>
A laminated film of polypropylene resin layer (30 μm) / stretched polyethylene terephthalate resin layer (12 μm) was used on both sides of a paper base material layer (basis weight 260 g / m ² ) with an isocyanate adhesive so that the polypropylene resin layer was on the outside. A laminated sheet having a surface composed of a polypropylene resin layer was formed on both sides of the paper substrate by sticking by a dry laminating method. The laminated sheet was punched out, and long windows were formed on both ends of the region to be the body member blank at the outer portion including the edge.

  A laminate composed of a polypropylene resin layer (20 μm) / ethylene-vinyl alcohol copolymer layer (12 μm) / inorganic oxide vapor deposited barrier film (12 μm) / polypropylene resin layer (20 μm) is formed by an ethylene-vinyl alcohol copolymer layer. Laminated on the laminated sheet by extrusion lamination method with polypropylene resin so that it comes to the paper substrate layer side, and at the same time, a polypropylene resin film (30 μm) as a sealant is laminated on the other side of the laminated sheet by extrusion lamination method with polypropylene resin. The inner surfaces were joined and integrated at the position of the long window.

Thereafter, a paper cup was molded and evaluated in the same process as in Example 1.
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 bonding was performed from above and below to flatten the upper surface of the flange.
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>
A paper cup was prepared in the same manner as in Example 2 except that a polymetaxylylene adipamide (MDX nylon) resin film was used instead of the ethylene-vinyl alcohol copolymer layer.
This paper cup was formed without a step at the 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. This paper cup was seen to have some cracks on the cup surface as seen from the outer surface of the lower end edge of the barrel member, but after putting water as a content and sealing with a lid, it was kept in hot water for 30 minutes. Although the container was boiled, no abnormality was observed in the appearance.

<Comparative Example 1>
A long window was formed on a sheet made of a paper base material (basis weight 260 g / m ² ).
Next, a laminated sheet composed of a polypropylene resin layer (30 μm) / polyethylene terephthalate resin layer (12 μm) / polyethylene resin layer (30 μm) is formed on the surface of the paper substrate of the sheet, and a polypropylene resin layer (30 μm) / inorganic oxidation is formed on the back surface. A laminated sheet composed of a material vapor deposition barrier film (12 μm) / polypropylene resin layer (30 μm) was laminated by extrusion lamination, and 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 portion (21) of the bottom member having a circular peripheral portion (21) raised downward is joined to the lower inner surface of the body portion.

Then, using a cup molding machine, the lower end edge of the body part is joined to the inner surface of the lower part of the body part so that the outer surface of the peripheral part of the bottom member is joined, and further, the peripheral part is covered along the inner surface of the bottom incurl mold. Was bent inward from the outside, joined to the inner surface of the peripheral edge of the bottom member, and crimped with a knurling to form an annular leg having a diameter of 52 mm. At this time, many hole scratches could be confirmed on the outer surface of the lower edge of the barrel member pressure-bonded by the knurling.
After filling with water as a content and sealing with a lid, boiling in hot water for 30 minutes, it was confirmed that the paper base was covered with hot water that had entered from the curled surface of the bottom of the container, and the appearance was confirmed. An abnormality occurred.

  In the paper cup of Comparative Example 1, many holes were generated on the surface of the member due to friction with the knurling during molding at the bottom portion. On the other hand, in the paper cups of the present invention of Examples 1 to 3, abnormalities in appearance such as swell of the paper base material are caused by heating in hot water even when the occurrence of hole scratches is confirmed on the surface. I couldn't see it.

  As described above, in the paper cup of the present invention, the thermoplastic resin layer provided on at least one side of the blank is composed of a gas barrier layer made of a metal or inorganic compound vapor-deposited plastic film, and ethylene provided on the paper substrate side of the gas barrier layer. -By containing a protective resin layer made of either vinyl alcohol copolymer, nylon, or polyvinylidene chloride, damage during molding is suppressed, and hot water retort treatment does not cause hot water inside the cup base paper. Was able to make a barrier paper cup that does not penetrate.

  Furthermore, in the paper cup of the present invention, a hot water retort treatment that has a strong resistance to penetration of hot water from not only the end surface of the member but also from the surface is possible by adopting a complementary structure against a decrease in barrier properties due to cracks in the barrier layer Paper cups can be manufactured stably. In addition, the transportability was improved due to the improved ability to retain the barrier property against the abrasion of the paper cup surface.

1 ... Paper substrate 2a ... Gas barrier layer 3 ... Laminated sheet 40 ... Thermoplastic resin layer (inside)
40a ... Sealant layer (PP)
40b ... Protective resin layer (EVOH layer or Ny layer or PVDC layer)
41 ... Thermoplastic resin layer (outside)
41a ... Sealant layer (PP)
41b ... Protective resin layer (EVOH layer or Ny layer or PVDC layer)
4... Resin part 4 a... Extending resin part 4 b .. Folded resin part 4 c... Extending resin part 4 d .. Folded resin part 10 .. Body member blank 11 .. Side edge 12 having resin part. Side edge 13 having a 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 C1 ... Frustum mold C2 ... Bottom incurl mold C3 ... Knurl C4 ... Expander

Claims (8)

A blank portion composed of a paper-based laminated sheet with thermoplastic resin layers provided on the inner and outer surfaces, and having a body bonding portion in which one side edge is superimposed on the other side edge In the paper cup, the thermoplastic resin layer provided on the outer surface side of the paper substrate is composed of a gas barrier layer made of a metal or inorganic compound vapor-deposited plastic film, and an ethylene-vinyl alcohol copolymer provided on the paper substrate side of the gas barrier layer. paper cups, characterized in that it contains a body or Ranaru protective resin layer. The paper cup according to claim 1, wherein a protective resin layer included in the thermoplastic resin layer provided on the outer surface side is provided on a surface of the gas barrier layer on the paper substrate side.   The thermoplastic resin layer including a gas barrier layer provided with a protective resin layer is laminated on a paper base material through a laminated film whose surface side is polypropylene resin by extrusion lamination of polypropylene resin. Paper cup. The paper cup according to claim 1, wherein a protective resin layer included in the thermoplastic resin layer provided on the outer surface side is provided on a surface of the paper base on the gas barrier layer side. The side edge located inside the overlapping part of the blank has a folded resin part that is folded back to the outer surface side of the base material from the side edge of the paper base material. side edges located outside of the overlapping portion is characterized by having a resin portion extending from a side edge of said paper substrate, a paper cup according to any one of claims 1 4. Resin portion extending from a side edge located outside of the overlapping portions of the blank, characterized by having a folded resin portion folded back on the outer surface or inner surface of the paper substrate, claims 1-5 The paper cup of any one of these. The resin part extending from the side edge located outside the overlapping part of the blank is overlapped and pressure-bonded to the blank inside the overlapping part. A paper cup according to claim 1. Said 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, the paper cup as claimed in any one of claims 1 7.

Images