JP2000229660A - Paper cup container - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture a paper cut container of superior processability and leakage preventing properties. SOLUTION: A bottom paper is wound and tightened below a body formed of a cylindrical body paper and an outer facing curling section is formed on the upper opening edge of a container. In that case, the container is manufactured by using a laminate with an ethylene -α.olefin copolymer formed of a paper layer 11 as a main body and polymerized by using a single site catalyst as an innermost layer 15. The sealing properties of a body sticking section and a knurl sealing section around the bottom plate are improved to provide the superior leakage preventing properties. Also the innermost layer 15 is provided with the superior low temperature sealing properties, and the bubbling control effect is provided by lowering the sealing temperature.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention belongs to the technical field of paper cup containers used for snacks, liquid distribution, and the like.

[0002]

2. Description of the Related Art FIG.
Shown in This paper cup container C is formed by winding a bottom plate 3 around a lower part of a body paper 2 bonded at a body bonding part 1 and forming an outward curl part 4 at an upper opening edge. That is, it is composed of a fan-shaped body paper 2 serving as a cylindrical body and a circular bottom paper 3 wound around the lower inside of the body. As a packaging material used for the body paper and the bottom paper, a laminate having specifications such as cup base paper / PE and PE / cup base paper / PE is generally used. Other materials, for example, an aluminum foil, a plastic film including a film subjected to various kinds of vapor deposition, and the like may be laminated on the front and back of the cup base paper. Also,
Due to its structure, the paper cup container has seal portions at two places, a body sticking portion and a knurled seal portion around the bottom plate. Therefore, LDPE is used as the innermost heat-sealable synthetic resin, and the adhesiveness is improved. LDPE grades are sufficiently selected to ensure the quality of the products, and even the most suitable ones are selected, and the production is performed with great care to maintain the molding conditions properly.

[0003]

As described in the prior art, the grade of the LDPE of the innermost layer of the laminate constituting the paper cup container is sufficiently selected, and the production is performed with great care. However, there still remain problems such as poor sealing due to variations in molding conditions and the like, and bubbling is likely to occur when an Al foil is used for the laminate constituting the paper cup container during lamination. In addition, leakage occurred due to pinholes and missing seals.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a paper cup container excellent in workability and leakage prevention.

[0005]

In order to solve the above-mentioned problems, a paper cup container according to the present invention is characterized in that a bottom paper is wound around a lower part of a cylindrical body and a curl is outwardly curled at an upper opening edge. A paper cup container having a part formed therein, wherein the innermost layer is an ethylene-α-olefin copolymer (hereinafter referred to as S-PE) mainly composed of a paper layer and polymerized using a single-site catalyst. It is characterized by being manufactured using a body.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION A single-site catalyst (including a metallocene catalyst, so-called Kaminski catalyst) used in the paper cup container of the present invention has a feature that active points are uniform (single-site). The single-site catalyst is a catalyst comprising a metallocene-based transition metal compound and an organoaluminum compound, and may be used while being supported by an inorganic substance.

Here, as the metallocene transition metal compound, for example, a transition metal selected from group IVB [titanium (Ti), zirconium (Zr), hafnium (H
f)] includes a cyclopentadienyl group, a substituted cyclopentadienyl group, an indenyl group, a substituted indenyl group, a tetrahydroindenyl group, a substituted tetrahydroindenyl group,
A fluorenyl group or a substituted fluorenyl group has one or two bonds, or a bond in which two of these groups are cross-linked by a covalent bond, and a hydrogen atom, an oxygen atom, a halogen atom, an alkyl group , An alkoxy group, an aryl group, an acetylacetonate group, a carbonyl group, a nitrogen molecule, an oxygen molecule, a Lewis base, a substituent containing a silicon atom,
Those having a ligand such as an unsaturated hydrocarbon are exemplified.

Further, as the organic aluminum compound,
Examples thereof include alkyl aluminum, and a chain or cyclic aluminoxane. Here, as the alkyl aluminum, triethyl aluminum, triisobutyl aluminum, dimethyl aluminum chloride, diethyl aluminum chloride, methyl aluminum dichloride,
Ethyl aluminum dichloride, dimethyl aluminum fluoride, diisobutyl aluminum hydride,
Examples thereof include diethyl aluminum hydride and ethyl aluminum sex chloride. The chain or cyclic aluminoxane is produced by bringing alkyl aluminum into contact with water. For example, it can be obtained by adding alkyl aluminum at the time of polymerization and adding water later, or by reacting water of crystallization of a complex salt or water absorbed by an organic / inorganic compound with alkyl aluminum.

Examples of the inorganic substance supporting the single-site catalyst include silica gel, zeolite, and diatomaceous earth. Examples of the polymerization method include bulk polymerization, solution polymerization, suspension polymerization, gas phase polymerization, and the like. These polymerizations may be a batch method or a continuous method. The polymerization conditions are usually as follows: polymerization temperature: -100 to 250 ° C, polymerization time:
5 minutes to 10 hours, reaction pressure: normal pressure 300 kg / m ² .

The α-olefin which is a comonomer copolymerized with ethylene includes propylene, 1-butene and 3-olefin.
Methyl-1-butene, 4-methyl-1-pentene, 1-
Hexene, 1-octene, decene and the like can be mentioned. These α-olefins may be used alone or in combination of two or more.

The mixing ratio of the α-olefin is preferably 1 to 50 mol%. The ethylene-α-olefin copolymer includes an antioxidant, an ultraviolet absorber, an antistatic agent, an antiblocking agent, a lubricant (fatty acid amide), a flame retardant, an inorganic and organic filler, a dye, a pigment, and the like. You may add suitably.

The physical properties of the ethylene-α-olefin copolymer polymerized using the single-site catalyst are, for example,
Molecular weight: 5 × 10 ^{1 to} 5 × 10 ⁴ , density [d]: 0.8
9 to 0.95 g / cm ³ , melt index [M
I]: 0.1 to 50.

The innermost layer S-PE of the laminate constituting the paper cup container has a density [d] of 0.90 to 0.92.
g / cm ³ , preferably 0.91 to 0.92 g / cm ³
Use If the density is less than 0.90 g / cm ³ , the suitability for blank removal is poor, and if it exceeds 0.92 g / cm ³ , the sealing property is poor. The melt index [MI] of the S-PE used is 4 to 10,
The melting point [Tm] is 100 to 110 ° C.

Further, by blending LDPE with 10 to 50 wt%, preferably 30 to 50 wt%, of S-PE, which is the innermost resin in the laminate, the low temperature sealing property is slightly lowered, but the suitability for removal is improved. be able to. In this case, the blend amount of LDPE is 10 wt%.
If less than 50%, the removability deteriorates, and if it exceeds 50% by weight, the sealing performance deteriorates. The density [d] of the LDPE to be blended is 0.71 to 0.925 g / cm ³ , and the melt index [MI] is 4 to 10.

The laminate constituting the paper cup container of the present invention may contain at least one barrier layer, if necessary. As this barrier layer, aluminum foil is generally used. In addition to aluminum foil, various kinds of vapor deposition (silica,
It is also possible to use a film that has been processed (eg, aluminum, alumina).

The layer structure of the conventional paper cup container is paper / PE, PE / paper / PE, paper / HM / AL / PE / OP.
E / PE, PE / paper / HM / AL / PE / OPE / PE
In the present invention, a paper cup container is manufactured by using a laminate in which at least the innermost layer of PE is replaced with S-PE.

Further, by adding an anti-blocking agent and a slip agent to S-PE, which is the resin of the innermost layer, it is possible to improve the slipperiness with respect to a molding machine.

[0018]

(Example 1) FIG. 2 is used as the body paper of a paper cup container.
Was produced. First, as a first step, a single-side coated paper (basis weight 290 g / m ² ) is used for the paper layer 11, and the uncoated surface is subjected to a corona treatment, and then the LDPE
(D: 0.917 g / m ³ , MI: 9.5, Tm: 10
6 ° C) by extrusion coating with a thickness of 15 μm
A PE layer 12 is formed, and an aluminum foil 1 having a thickness of 7 μm is formed thereon.
3 were pasted together. In the subsequent second step, EMAA (d: 0.930 g / cm ³ , MI:
7.0, Tm: 100 ° C) and S-PE (d: 0.912)
g / cm ³ , MI: 8.0, Tm: ° C.), and the EMAA layer 14 having a thickness of 20 μm and the S-
The PE layer 15 was laminated.

On the other hand, the laminate serving as the bottom plate was prepared by changing the paper layer 11 to cup base paper (basis weight: 170 g / m ² ), and using the same specifications for the other components, and by the same process.

(Example 2) d: 0.90 as S-PE
Laminates to be a body paper and a bottom plate were respectively produced in the same manner as in Example 1 except that those having 4 g / cm ³ , MI: 7.7, and Tm: 103 ° C. were used.

(Embodiment 3) The EMAA layer and the S-
The thicknesses of the PE layers were each set to 10 μm, and the laminates serving as the body paper and the bottom plate were produced.

(Embodiment 4) The EMAA layer and the S-
The thicknesses of the PE layers were each set to 10 μm, and the laminates serving as the body paper and the bottom plate were produced.

Example 5 LDPE (d:
0.917 g / cm ³ , MI: 7.2, Tm: 106
(C) was used in the same manner as in Example 1 except that a blend of 30 wt%) was used to produce a laminated body to be a body paper and a bottom plate.

(Example 6) LDPE (d:
0.917 g / cm ³ , MI: 7.2, Tm: 106
C.) was prepared in the same manner as in Example 1 except that a blend of 50 wt%) was used.

(Example 7) LDPE (d:
0.917 g / cm ³ , MI: 7.2, Tm: 106
C.) was prepared in the same manner as in Example 2 except that a blend of 30 wt%) was used.

Example 8 LDPE (d:
0.917 g / cm ³ , MI: 7.2, Tm: 106
C.) was prepared in the same manner as in Example 2 except that a blend of 50 wt%) was used.

(Comparative Example 1) LDPE instead of S-PE
(D: 0.923 g / cm ³ , MI: 3.7, Tm: 1
(11 ° C.) except that the laminated body serving as the body paper and the bottom plate was produced in the same manner as in Example 1.

(Comparative Example 2) LDPE instead of S-PE
(D: 0.923 g / cm ³ , MI: 3.7, Tm: 1
(11 ° C.) except that the laminated body serving as the body paper and the bottom plate was prepared in the same manner as in Example 3.

"Evaluation of Machine Suitability" The laminates obtained in Examples 1 to 8 and Comparative Examples 1 and 2 were evaluated for slipperiness with respect to a cup molding machine, suitability for blanking, and suppression of bubbling. The results are as shown in Table 1, where x is inferior, Δ is slightly inferior, ○ indicates normal, and ◎ indicates good.

[0030]

[Table 1]

"Seal Check" Using the laminates obtained in Examples 1 to 8 and Comparative Examples 1 and 2, paper cup containers were produced using a cup molding machine, and each of the obtained paper cup containers was prepared.
The sealing property was confirmed for 0 pieces. Table 2 shows the results.

[0032]

[Table 2]

[0033]

As described above, the paper cup container of the present invention uses a laminate mainly composed of a paper layer and having an innermost layer of an ethylene-α-olefin copolymer polymerized using a single-site catalyst. By making it, the sealability of the innermost layer can be improved and the slipperiness will be good, so
The sealing property of the knurled seal portion around the body sticking portion and the bottom plate is improved, and a paper cup container of stable quality with excellent leakage prevention can be produced with high efficiency.

The ethylene-α-olefin copolymer polymerized by using a single-site catalyst is excellent in low-temperature sealing properties. Therefore, by lowering the sealing temperature, the effect of suppressing bubbling and the generation of cracks in the deposited film can be obtained. Is obtained.

The resin in the innermost layer has a density of 0.90 to 0.90.
The use of 0.92 g / cm ³ can improve the blanking suitability by a machine.

[Brief description of the drawings]

FIG. 1 is a perspective view of a paper cup container.

FIG. 2 is a cross-sectional view illustrating an example of a laminate forming a paper cup container.

[Explanation of symbols]

 C Paper cup container 1 Body sticking part 2 Body paper 3 Bottom plate 4 Outward curl part 11 Paper layer 12 LDPE layer 13 Aluminum foil 14 EMAA layer 15 S-PE layer

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B65D 1/26 B65D 1/26 CF term (Reference) 3E033 AA08 BA10 BA14 BA15 BB08 CA16 DA08 DD01 GA02 3E086 AA22 AB01 AD06 BA04 BA14 BA15 BB51 BB55 BB90 CA01 CA11 4F100 AB10 AK06B AK62B AK70 AL05B BA03 BA07 BA10A BA10B BA10C DG10A EH23 GB16 GB23 JA13B JD01 JD01C JL02 YY00B

Claims (4)

[Claims] 1. A paper cup container comprising: a bottom body wound around a cylindrical body formed of a cylindrical body; and an outward curled portion formed at an upper opening edge. A paper cup container manufactured using a laminate having an innermost layer of an ethylene-α-olefin copolymer polymerized using a system catalyst. 2. The resin of the innermost layer has a density of 0.90 to 0.9.
Paper cups container according to claim 1 which is 2 g / cm ^3. 3. An innermost resin layer of 10 to 50 watts of LDPE.
The paper cup container according to claim 1 or 2, wherein t% is blended. 4. The paper cup container according to claim 1, wherein the laminate includes at least one barrier layer.