JP4940972B2 - Paper cup and manufacturing method thereof - Google Patents

Description

  The present invention relates to a method for producing a paper cup, and more specifically, a biomass resin is used for reducing environmental burden, and further for resource saving, recycling society, prevention of global warming, activation of agriculture, and the like. The present invention relates to a paper cup and a manufacturing method thereof.

  In the present specification, “ratio”, “part”, “%” and the like indicating the composition are based on mass unless otherwise specified, and the “/” mark indicates that they are integrally laminated. “Biomass” is “biologically derived”, “biomass resin” is “plant-derived resin”, “PLA” is “polylactic acid”, “LDPE” is “low-density polyethylene”, and “EMAA” is “ethylene-methacrylic”. “Acid copolymer”, “PEI” is an abbreviation, functional expression, common name, or industry term for “polyethyleneimine”.

  (Main use) Main uses of the paper cup manufactured by the paper cup manufacturing method of the present invention include juices, beverages such as soft drinks and alcohol, liquids such as ice cream, frozen confectionery and yogurt, viscous, solid In addition to reducing the burden on the environment with liquid food containers that contain food, it has also been advocated for resource saving, recycling society, prevention of global warming, and activation of agriculture. However, the application is not particularly limited as long as it is an application that reduces the burden on the environment and further requires resource saving, a recycling society, prevention of global warming, activation of agriculture, and the like.

(Background Art) Paper cups to be used such as containers for liquid foods that are liquid, viscous, or solid, require water resistance, and a resin layer, usually polyethylene or wax, is laminated on the inner surface of the paper cup. Paper cups are usually disposed of only once, so the amount of garbage increases and remains almost undegraded, leaving a heavy burden on the environment. There are also problems such as the destruction of the environment. Therefore, it is preferable to use a biomass material using biological resources. In the present specification, a plant-derived resin is particularly referred to as a biomass resin. If it is this biomass resin, even if it is incinerated after use, it will return to the plant through carbon dioxide, to the plant again through composting, etc. It is also effective in preventing global warming and revitalizing agriculture, and is also resource-saving because it does not use petroleum resources. However, when a biomass resin is used to make a container into a paper cup, there is a problem that it cannot be easily manufactured because the processability of the biomass resin such as the film forming processability and the container processability is poor.
Therefore, as a method for producing a paper cup using a biomass resin, even if a biomass resin that reduces the burden on the environment and further approaches resource-saving and recycling-oriented society is used, the film forming processability of the layer containing the biomass resin is suitable. However, it is required that a laminated body can be produced, and that a paper cup can be easily manufactured at a low cost and in large quantities with conventional equipment.

(Prior Art) Conventionally, a biodegradable composite material using only polylactic acid or a derivative thereof is known as a biodegradable material that is one of biomass resins (see, for example, Patent Document 1). However, it is related to the biodegradable composite material itself, and the production of the biodegradable composite material is not suitable for mass production by applying and hot pressing, and the biodegradable composite material is put into a practical use form such as a container. There is no description or suggestion of this processing method.
In addition, a sealing method is known that uses a biodegradable microorganism-produced polyester or aliphatic polyester and does not use a medium for bonding with hot air (see, for example, Patent Document 2). However, the hot air system has a drawback that the sealing conditions are limited to a narrow range and sufficient sealing strength cannot be obtained.
In addition, paper containers made of paper with a biodegradable plastic layered on paper, and paper containers made of a paper base material with a biodegradable plastic having thermal adhesiveness stretched uniaxially or biaxially on the inner surface are known. (See, for example, Patent Documents 3 and 4). However, only a known method (general theory) is described as a manufacturing method from laminated paper to a paper container, and no specific manufacturing method is described or suggested.
Furthermore, a lid made of a paper / biodegradable sealant layer (polylactic acid) is known (for example, see Patent Documents 5 to 6). However, an ultrasonic seal is exemplified as a method for sealing the lid and the paper cup. The seal portion includes a biodegradable sealant layer (polylactic acid) on the container side and a biodegradable sealant layer (polylactic acid) on the lid. Neither of these publications describes or suggests a seal between paper and a biodegradable sealant layer (polylactic acid).
Furthermore, the present applicant is also a cup-shaped seedling pot made of paper and biodegradable plastic, and a fast-degradable biodegradable plastic is bonded to one side of the paper, and the other side is degradable. Disclosed is a seedling pot characterized in that at least a body portion is formed in a cup shape with a slow degradable biodegradable plastic surface inside, using a laminated sheet bonded with a slow biodegradable plastic. (For example, refer to Patent Document 7). However, the seal of the body pasting part (the overlapping part of the side end part) for making the body part into a cylindrical shape protects the cross section of the laminated sheet from being exposed by folding one side of the blank by the skive hemming method. The other side is overlapped and side-sealed to form the body sticker, so it is a seal between biodegradable plastics, not a seal between paper and biodegradable plastics, but rather bonds between degradable plastics Therefore, there is also a description that heat fusion by hot air or the like is possible, which suggests difficulty in sealing paper and biodegradable plastic. Such a difficulty in sealing has been eliminated and the present invention has been achieved.

JP-A-4-334448 JP-A-6-62944 JP-A-6-64111 JP 2003-26143 A Japanese Patent Laid-Open No. 2004-231211 Japanese Patent Laid-Open No. 2004-231212 JP-A-9-98671

  In order to solve the above-described problems, the present inventors have made extensive studies and have completed the present invention. Its purpose is to reduce the burden on the environment, and even with the use of a biomass resin approaching a resource-saving, recycling-oriented society, the layer containing the biomass resin has good processability and can be made into a laminate. The manufacture of the paper cup is to provide a paper cup manufacturing method and a paper cup that can be easily manufactured using conventional equipment.

In order to solve the above problems, a paper cup manufacturing method according to the invention of claim 1 uses a body member having a resin layer made of a kneaded product of a biomass resin and a synthetic resin on one side of a paper base as a body part. In a method for manufacturing a paper cup using a bottom member having a resin layer made of a kneaded product of a biomass resin and a synthetic resin on at least one side of a paper base as a bottom part, the cylindrical body is formed with the resin layer of the barrel member inside, It is made so that the thermal bonding method of the trunk | paste part which piled up one part of the part was an ultrasonic system.
A paper cup according to a second aspect of the present invention is manufactured by the paper cup manufacturing method according to the first aspect.
A paper cup according to a third aspect of the present invention is the paper cup according to the second aspect, wherein the mixing ratio of the biomass resin and the synthetic resin in the resin layer is 50 to 75:50 to 25 on a mass basis.
A paper cup according to a fourth aspect of the present invention is the paper cup according to any one of the second to third aspects, wherein the biomass resin is a polylactic acid resin.
A paper cup according to a fifth aspect of the present invention is the paper cup according to any one of the second to fourth aspects, wherein the resin layer is laminated on a paper base material by an extrusion lamination method.

According to the present invention of claim 1, the processability of the layer containing the biomass resin can be improved to provide a laminate, and in the manufacture of a paper cup, a method of manufacturing a paper cup that can be easily manufactured with conventional equipment is provided. .
According to this invention of Claims 2-4, the paper cup using biomass resin which reduces the load to an environment and also approaches a resource-saving and recycling society is provided.
According to the present invention of claim 5, in addition to the effects of claims 2 to 4, the processability of the resin layer containing the biomass resin is good, the thickness difference of the resin layer is small, and the roll-to-roll method is stable and low. A paper cup is provided that can be produced at cost.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a perspective view of a paper cup showing an embodiment of the present invention.
FIG. 2 is a cross-sectional view taken along line AA ′ of FIG.
3 is a cross-sectional view taken along the line BB ′ of FIG.

  The paper cup manufacturing method of the present invention uses a body member 41 having a resin layer 23 made of a mixture of a biomass resin and a synthetic resin on one side of a paper base 21 as the body 11, and at least the paper base 21 as the bottom 13. In the manufacturing method of the paper cup 10 using the bottom member 43 which has the resin layer 23 which consists of a kneaded material of biomass resin and synthetic resin on one side, the resin layer 23 of the body member 43 is formed into a cylindrical shape, The thermal bonding method of the body pasting part 31 where one part is overlapped is an ultrasonic method. Moreover, the paper cup 10 of the present invention manufactured by the method of manufacturing the paper cup of the present invention is preferably such that the blending ratio of the biomass resin and the synthetic resin in the resin layer 23 is 50 to 75:50 to 25 on a mass basis, and the biomass. The resin is a polylactic acid-based resin, and the resin layer 23 is laminated on the paper substrate 21 by an extrusion lamination method.

(Paper base material) Specifically, the paper base material has formability, bending resistance, rigidity, and the like. For example, a paper base such as bleached or unbleached paper, paperboard, processed paper, etc. Although there are materials, etc., cup base paper that is stretchable and has good suitability for producing paper cups is preferred. Further, the paper base material may contain various additives. The paper substrate, those having a basis weight of about 80~600g / m ² position, preferably, it is desirable to use a basis weight of about 100~450g / m ² position. The paper base material can be used for the body member and the bottom member, and the paper base material for the body member and the bottom member may be the same or different. The body member may have a resin layer on one side of the paper substrate, and the bottom member may have a resin layer on at least one side of the paper substrate, and may have a resin layer on both sides.

  (Resin layer) The resin layer 23 is made of a resin composition composed of a kneaded product of a biomass resin and a synthetic resin, and the blending ratio of the biomass resin and the synthetic resin is 50 to 75:50 to 25 on a mass basis. In addition, additives such as a colorant, a pigment, an extender pigment, a filler, a lubricant, a plasticizer, a surfactant, and a bulking agent may be added to the resin layer.

  (Biomass resin) Examples of the biomass resin include starch, polylactic acid resin, microorganism-produced polyester, aliphatic or aromatic polyester, and the like. Biomass resins include those that biodegrade and those that do not biodegrade. Any of these may be used, preferably a biodegradable resin, and particularly preferably a polylactic acid resin in terms of biodegradability and strength.

  (Polylactic acid-based resin) Polylactic acid-based resin may contain 50% by weight or more of lactic acid component in terms of monomer mass. For example, polylactic acid, lactic acid and other aliphatic hydroxycarboxylic acids Examples thereof include a copolymer, a copolymer of lactic acid, an aliphatic polyhydric alcohol and an aliphatic polybasic acid, and a mixture of any one of the above. Examples of lactic acid include L-lactic acid, D-lactic acid, DL-lactic acid or a mixture thereof, or lactide which is a cyclic dimer of lactic acid. Specifically, a polylactic acid resin “Lacia” (trade name) manufactured by Mitsui Chemicals, Inc. can be exemplified, and as its brand, for example, H-100, H-400, H-440, H-360, H -280, 100J, H-100E, M-151S Q04, M151S Q52, and the like.

  (Synthetic Resin) The synthetic resin to be mixed with the biomass resin is not limited, but a heat-sealing polyolefin resin or a modified product thereof is preferable. For example, LDPE, L-LDPE, PP, PS, ethylene-unsaturated carboxylic acid copolymer, ethylene-unsaturated carboxylic acid ester copolymer, acid-modified polyolefin, ionomer, which is a copolymer of olefin and other monomers Among them, an ethylene-unsaturated carboxylic acid copolymer, an ethylene-unsaturated carboxylic acid ester copolymer, an acid-modified polyolefin, an ionomer, or a combination thereof is more preferable. Details of each are described below.

(Ethylene-unsaturated carboxylic acid copolymer) As the ethylene-unsaturated carboxylic acid copolymer, there are ethylene-acrylic acid copolymer (EAA) and ethylene-methacrylic acid copolymer (EMAA). The unsaturated carboxylic acid unit content in the carboxylic acid copolymer is preferably 2 to 25% by weight, more preferably 5 to 20% by weight.
(Ethylene-unsaturated carboxylic acid ester copolymer) Examples of the ethylene-unsaturated carboxylic acid copolymer include ethylene-ethyl acrylate copolymer (EEA), ethylene-methyl acrylate copolymer (EMA), and ethylene-methacrylic acid. Examples include acid methyl copolymer (EMMA).
(Acid-modified polyolefin) Acid-modified polyolefin is an acid-modified polyolefin obtained by modifying a polyolefin resin such as polyethylene or polypropylene with an unsaturated carboxylic acid such as acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid or itaconic acid. There are resins.
(Ionomers) Examples of ionomers include those having side chain ion groups, those having carboxylic acid groups at both ends neutralized with metal ions, and those having an anion bound to a cation on the main chain. Not. For example, ethylene-methacrylic acid copolymer ionomer, ethylene-acrylic acid copolymer ionomer, propylene-methacrylic acid copolymer ionomer, propylene-acrylic acid copolymer ionomer, butylene-acrylic acid copolymer ionomer, ethylene-vinyl. A sulfonic acid copolymer ionomer etc. can be illustrated and you may use only 1 type or 2 or more types as needed. The unsaturated carboxylic acid unit content in the ionomer is preferably 2 to 25% by weight, particularly preferably 5 to 20% by weight, and more preferably an ethylene-methacrylic acid copolymer ionomer.

(Blend ratio) The blend ratio of the resin layer 23 is preferably about biomass resin: other resin = 10 to 90:90 to 10, more preferably 50 to 75:50 to 25 on a mass basis. Less than this range is less effective for reducing environmental impact, saving resources, and creating a recycling society. If this range is exceeded, a uniform film cannot be obtained when processing into a laminate, and a uniform film cannot be obtained. Adhesive strength is also weak. The melt flow rate (MFR) measured under the conditions of 190 ° C. and 2160 g load according to JIS K-7210 of the resin layer 23 is about 0.5 to 20 g / 10 minutes, preferably 1 to 15 g / 10. Min, more preferably 4-6 g / 10 min.
If it is less than this range, the processability at the time of EC processing is poor, the flow of the resin from the T die is poor, and the film is likely to break, and if it exceeds this range, the flow of the resin from the T die is prematurely disturbed or thick and uneven. And a uniform film cannot be obtained.

  (Mixing method) A method of blending and kneading a biomass resin and another resin (also referred to as a mixed resin) to obtain a resin composition is not particularly limited. For example, a uniaxial or multiaxial extruder, a mixer, etc. Known methods, and melt kneading is preferred.

  (EC) The kneaded resin composition is made into a resin layer by an extrusion lamination method and laminated on a paper substrate. The extrusion lamination method is a so-called method called extrusion coating (EC) by those skilled in the art. First, the extruded resin is heated and melted with an extruder, and is expanded and expanded in a necessary width direction with a T-die and extruded into a curtain shape. The molten resin is caused to flow down to a paper base and sandwiched between a rubber roll and a cooled metal roll, thereby forming an extruded resin layer, adhering to the base film, and laminating at the same time. It is a method that can be processed in the form of a winding and has extremely high production efficiency. However, biomass resins, especially polylactic acid resins, have low tension at the time of melting, and the extrusion lamination method has a large neck-in of the resin from the T-die. Particularly, both ends become thick and difficult to wind, resulting in uneven thickness of the resin layer. Since it is large and easily cut off, a thin resin layer could not be formed. Using the EC system, the temperature of the molten resin is about 180 to 300 ° C., preferably when the extruded resin composed of a mixture of biomass resin and synthetic resin is heated and melted by an extruder and extruded from a T-die in a curtain shape. It is about 210-280 degreeC, More preferably, it is about 230-270 degreeC. If it is less than this range, the neck-in of the resin from the T-die is large, and particularly the both end portions are thick and difficult to wind, and the thickness unevenness of the resin layer is large, and the film is likely to break. Moreover, since it exceeds the decomposition temperature of the resin beyond this range, the flow of the resin from the T die is disturbed or colored.

  In the present invention, by using a resin layer composition composed of a kneaded product of the aforementioned biomass resin and synthetic resin as an extrusion resin, there is little unevenness in thickness in the width direction, and roll-to-roll winding shape with existing conventional equipment. Can be processed at a very high production efficiency and can be easily mass-produced. The thickness of the resin layer containing the biomass resin in the extrusion lamination is about 5 to 200 μm, more preferably 20 to 100 μm. If it is less than this range, the sealing strength is insufficient and liquid leakage is likely to occur. If this range is exceeded, the performance becomes excessive and wasted.

  (AC) In order to firmly adhere the extruded resin to the paper substrate, an adhesion promoter or the like usually called an anchor coating agent (AC agent) may be applied, or instead of the anchor coating agent. , Easy adhesion treatment such as corona discharge treatment, plasma discharge treatment, ozone gas treatment may be performed. Examples of the anchor coating agent include organic titanium anchor coating agents such as alkyl titanates, isocyanate anchor coating agents, polyethyleneimine anchor coating agents, polybutadiene anchor coating agents, and polyurethane anchor coating agents. The anchor coating agent may be applied and dried by a known coating method such as roll coating or gravure coating. The thickness of the anchor coating agent is usually about 0.01 to 10.0 μm, preferably 0.1 to 5.0 μm.

  The laminate having the resin layer 23 made of a kneaded mixture of biomass resin and synthetic resin on at least one side of the paper base material 21 laminated by the extrusion lamination method in this way, even after incineration after use, through carbon dioxide gas to the plant, In addition, it is effective for the prevention of global warming, the activation of agriculture, and the like by approaching a recycling society from plants to biomass resin again through compost treatment, etc., and suppressing emission of carbon dioxide. Further, it does not use petroleum resources or saves resources because only a small amount of use is required.

(PEI) The paper substrate 21 may contain polyethyleneimine (PEI) or a polylactic acid-based resin. As a method of inclusion, the paper substrate 21 may be formed or coated. As a method of applying to the paper substrate surface, a solution such as water, alcohol or / and an organic solvent may be applied by impregnation on the paper substrate, stamp coating, roll coating, spray coating or the like and dried. The part to be thermally bonded is indispensable, and of course the entire surface may be used. By doing so, a blank (barrel member) punched into a truncated cone shape is wound in a cylindrical shape on the inside of the resin layer, and the side end portions thereof are partially overlapped and sealed to form a cylindrical barrel. In this case, even when sealing the heterogeneous material between the resin layer surface containing the biomass resin and the paper substrate surface, the adhesion is improved, and sufficient adhesion can be obtained even under lower conditions. The coating amount of polyethylene imine (PEI), usually 0.001g / m ² ~5g / m ² approximately, and preferably from ^{0.01g / m 2 ~1g / m 2} . Below this range, the effect of improving adhesiveness is low, and even if it exceeds this range, the effect is saturated and wasted.

  (Paper Cup Manufacturing) A known manufacturing method for the paper cup 10 is as follows: (1) the body member 41 is prepared, (2) the bottom member 43 is prepared, and (3) the body member 41 is punched into a truncated cone. (4) The bottom member 43 is punched in a circular shape to form a bottom material blank. (5) The body blank plate is wound in a cylindrical shape inside the resin layer 23, and the side edges are partially overlapped. Together, it is a body pasting portion 31, the body pasting portion 31 is heated and pressed to form a tubular body 11, and (6) the outer periphery of the bottom plate blank is placed on the bottom end of the tubular body 11. Insert a bottom member that is formed into an upright molded part 33 by standing upright into a cylindrical shape, and blow the hot air or the like to the part to be joined between the bottom end part of the body part into which the bottom member is inserted, and to the part to be joined The existing resin layer 23 is heated and melted, and then the cylindrical cup body is formed by a curling mold. Bend the end part inward and place it on the upright forming part 33 that constitutes the bottom part, so that the cylinder pasting part between the tip part of the cylindrical cup body part and the upright molding part 33 of the bottom part from the inner diameter side. By knurling with the knurling, the cup barrel portion 11 and the bottom portion 13 are tightly bonded to seal the joint, and (7) the upper end portion of the barrel portion 11 is curled outward to form a curl 15. In such a paper cup molding method, there is a restriction on the material used, and the material used is specified at present.

  As the (hot air) sealing method, a hot air method is usually used. The resin layer of a general paper cup is wax, polyethylene or polypropylene, and in this case, it is very efficient. However, when a resin layer containing a biomass resin is used, the adhesiveness between the resin layer and the paper substrate is not sufficient, and there is a risk that the liquid may bleed and leak.

  (Ultrasound) The low temperature hot air according to the prior art of Patent Document 2 has a small heat capacity, so that a sufficient seal can be achieved only under narrow conditions, and the adhesive state of the seal is not stable. Therefore, in order to improve the adhesiveness between the resin layer containing the biomass resin and the paper base material, the body pasting portion 31 is not a hot air method, but the body member is wound in a cylindrical shape, and both end portions are partially overlapped. And it was found that even when the resin layer contains a biomass resin, it can be satisfactorily sealed by using the ultrasonic pasting portion 31. That is, even a resin layer containing a biomass resin can have both good processability in the above-described extrusion lamination and good sealability of the body portion. Moreover, since the seal | sticker of the front-end | tip part of a cylindrical cup trunk | drum and the standing-up molding part 33 of a bottom part has a part of resin layers, the method is not ask | required.

  Therefore, it is relatively easy to apply a contact layer having stable adhesiveness, and the cradle is brought into contact with the resin layer containing the biomass resin that is inside the cylindrical body member, An ultrasonic horn is applied from the outside of the barrel member corresponding to the contact portion, and ultrasonic vibration is generated in the horn to seal and bond the barrel-paste portion. With such an ultrasonic seal, the ultrasonic vibration direction and the sealing surface are the same, and there is no vibration absorption of the paper, and a uniform sealing property is obtained. The ultrasonic seal can be easily and safely sealed with an apparatus, and can provide a stable adhesive force. Further, a cradle may be applied to the outside of the body member, and an ultrasonic horn may be applied from the inside of the body member to seal and bond the horn while generating ultrasonic vibration. The ultrasonic horn may be applied through another molded part.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention further in detail, it is not limited to this.

(Example 1) As a body member of a paper cup, using a cup base paper having a basis weight of 255 g / m ^{2 as} a paper base material, the following resin layer composition is applied at 260 ° C. while subjecting one side to in-line corona treatment. A resin layer having a thickness of 30 μm was formed by an extrusion lamination method to obtain a laminate.
As the resin layer composition, 60 parts by mass of Lacia H-100 (manufactured by Mitsui Chemicals, trade name of polylactic acid) and 40 parts by weight of Himiran 1652 (product of Mitsui Polychemicals, trade name of ionomer) are added and kneaded by heating. (MFR 3.5 g / 10 min) was used.
As the bottom member of the paper cup, using a cup base paper having a basis weight of 255 g / m ^{2 as} a paper base, the resin layer composition is thickened by extrusion lamination method at 260 ° C. while performing in-line corona treatment on one side. A resin layer having a thickness of 30 μm was formed by an extrusion lamination method at 245 ° C. while applying a corona treatment to the opposite surface in line with the resin layer. A laminate of double-sided resin layers composed of paper base material 21 / resin layer 23 was used.
The body member is punched into a truncated cone shape to form a blank plate, the blank plate is wound in a cylindrical shape on the inside, and the side end portions are partially overlapped to form a body pasting portion 31, While receiving the inner side with a cradle, a cylindrical barrel was formed by irradiating an ultrasonic wave for 0.158 seconds with an output of 97% (MAX 4000 W) from an ultrasonic horn from the outer side of the barrel pasted part.
A bottom member in which the outer periphery of the bottom plate blank is formed upright in a cylindrical shape is inserted into the bottom end of the cylindrical body, and the bottom end of the body into which the bottom is inserted is connected to the joining portion with hot air or the like The resin layer existing at the joining portion is heated and melted, and then the tip of the cylindrical cup body is bent inward by a curling die to form the upright forming portion constituting the bottom portion. Cover the top part of the cylindrical cup body and the upright molded part of the bottom part by knurling from the inner diameter side with knurls, so that the cup body part and the bottom part are closely bonded to each other. Sealed.
The upper end of the barrel was curled outward to obtain a paper cup of Example 1 having a capacity of 500 ml.

  (Example 2) As a resin layer composition, Himaslan 1652 (Mitsui Polychemical Co., Ltd., ionomer product name) 25 parts by mass was added to 75 parts by mass of Lacia H-100 (Mitsui Chemicals Co., Ltd., polylactic acid product name). Then, a paper cup of Example 2 was obtained in the same manner as Example 1 except that the one kneaded with heat (MFR 5.0 g / 10 min) was used.

  (Example 3) As a resin layer composition, 20 parts by mass of Hi-Milan 1652 (Mitsui Polychemical Co., Ltd., ionomer product name) was added to 80 parts by mass of Lacia H-100 (Mitsui Chemicals Co., Ltd., product name of polylactic acid). Then, a paper cup of Example 3 was obtained in the same manner as in Example 1 except that the one kneaded with heat (MFR 6.0 g / 10 min) was used.

  Example 4 As a resin layer composition, 70 parts by mass of LDPE (Mirason 16P, manufactured by Mitsui Chemicals, Inc.) is added to 30 parts by mass of Lacia H-100 (manufactured by Mitsui Chemicals, polylactic acid product name), followed by heating and kneading. A paper cup of Example 4 was obtained in the same manner as in Example 1 except that the obtained product (MFR 5.2 g / 10 min) was used.

(Evaluation method) The adhesion state was visually observed by a test method in which the paper base surface of the body member and the resin layer surface of the body member were overlapped and sealed after being sealed with an ultrasonic method and a hot air method.
When the body members are peeled apart, 80% to 100% of the seal part is peeled off by "◎", and 50% to 79% of the seal part is peeled by "○", 49% In the following, those that peel off are indicated by “Δ”, and those that do not peel off are indicated by “×”. “◎” and “◯” were acceptable, and “△” and “x” were unacceptable. The paper peeling phenomenon is a phenomenon that occurs when the paper substrate, which is the weakest part, cohesively breaks down when the adhesion between the paper surface and the resin layer surface is good, and is an indicator of good adhesion.

(Test method) The ultrasonic method was performed by irradiating an ultrasonic wave for 0.158 seconds with an output of 97% (MAX 4000 W) from an ultrasonic horn.
The condition of the hot air method is that after hot air of a predetermined temperature (200, 500, 600 ° C.) is blown twice for 0.3 seconds at a pressure of 150 kPa, an unheated tool steel bar is used. Pressurization for 0.3 seconds was performed once under a load of 500 N. The results are shown in Table 1.

(Evaluation result) As for the result of the ultrasonic method, Examples 1 to 4 passed with a ◯ mark. However, the results of the hot air system were also unacceptable as in Examples 1 to 4 at 200 ° C. as x, and at 500 and 600 ° C. as Δ.
In addition, water containing 0.3% neutral surfactant and 0.5% red ink (to make it easy to see leakage) was poured into the paper cup 10 of Examples 1 to 4, and the lid was fitted. Although it was allowed to stand at room temperature for 10 minutes, there was no leakage, the paper cup was not colored, and no abnormality such as deformation was observed. In addition, when the body sticking part of the body part of the paper cup in which the contents were discarded was destroyed, all of the seal parts were 50% or more in good condition.

It is a perspective view of the paper cup which shows one Example of this invention. It is AA 'sectional drawing of FIG. It is BB 'sectional drawing of FIG.

Explanation of symbols

10: Paper cup 11: Body part 13: Bottom part 15: Curl 21: Paper base material 23: Resin layer 31: Body sticking part 33: Standing molding part 41: Body member 43: Bottom member

Claims (5)

A body member having a resin layer made of a mixture of biomass resin and synthetic resin on one side of a paper base material as a body part, and a resin layer made of a mixture of biomass resin and synthetic resin on at least one side of the paper base material as a bottom part In the manufacturing method of the paper cup using the bottom member having,
Wherein the tubular shape by the resin layer of the body member to the inner, heat-bonding methods Doha portion superimposed a portion of both side ends Ri ultrasonic type der,
The blending ratio of the biomass resin and the synthetic resin in the resin layer is 50 to 75:50 to 25 on a mass basis,
The synthetic resin is an olefin resin, an ethylene-unsaturated carboxylic acid copolymer, an ethylene-unsaturated carboxylic acid ester copolymer, an acid-modified polyolefin, an ionomer, or a combination thereof . Production method.   A paper cup manufactured by the method for manufacturing a paper cup according to claim 1. The paper cup according to claim 2 , wherein the biomass resin is a polylactic acid resin. Paper cup according to claim 2 or 3 wherein the resin layer is characterized by comprising laminated to the paper substrate in an extrusion City lamination Activation Method. The paper cup in any one of Claims 2-4 in which the said paper base material contains a polyethyleneimine or polylactic acid-type resin.

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