JP2664309B2 - Liquid paper container - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid paper container used for sake, fruit juice drinks, coffee drinks, and the like, and relates to a liquid paper container using a polyester resin as the innermost layer of a laminated constituent material in contact with the contents. It is.

[0002]

2. Description of the Related Art In recent years, liquid paper containers have been replaced with conventional glass containers and metal containers. It has come to be used in large quantities in room temperature liquid foods that require storage. These liquid paper containers use relatively simple laminated material such as [outside] polyethylene / paper / polyethylene [inside] in the chilled flow type, and the comparative example shown in FIG. [Outside] polyethylene layer (31) / paper layer (32) / polyethylene layer (33) / aluminum foil layer (34) / polyethylene terephthalate layer (35) / polyethylene layer (36) [inside] The laminated constituent material (30) was used.

[0003]

In these laminated constituent materials, polyethylene is usually used for the innermost layer in contact with the contents in both the chilled flow type and the room temperature flow type. However, when polyethylene is used for the innermost layer, the problem that the low molecular weight polyethylene component elutes into the content and the polyethylene odor migrates to the content, and conversely, the active ingredient of the content, for example, of juice There has been a problem that aroma components such as limonene (C ₁₀ H ₁₆ ) are adsorbed. Because of this,
Polyester-based resins that do not change the odor or taste of the contents have been used for packaging materials for foods.

In the liquid paper container (40),
As shown in FIG. 4, the cut surface (4
The edge protection structure (4) has a folded structure at the end of the laminated material so that 2) does not directly contact the contents.
1) is used. This is one of the laminated constituent materials
The end is folded back to the outer layer side and laminated on the folded portion
The other end of the material is overlapped, and the overlapping portion (43) of the innermost resin (36) facing each other is firmly heat-sealed by a frame seal. The inventors have
In consideration of the above-mentioned off-flavors and changes in taste of the contents, polyester resins in which the acid component is terephthalic acid and the glycol component is ethylene glycol, which are currently commercially available,
I used it for the innermost layer of the laminated material, but unfortunately, the surface treatment of the polyester resin in the innermost layer was oxidized by the frame treatment, and a seal with strong adhesive strength between the innermost resin in the edge protection structure Was not obtained. Naturally, the container had poor drop strength and impact resistance.

[0005]

According to a first aspect of the present invention, as shown in FIGS. 1 and 2, a paper layer (12) is used as a base layer, at least an outermost layer is a polyolefin layer (11), and A laminated constituent material (10) having an innermost layer composed of a polyester resin layer (16) is used, and one end of the laminated constituent material is used.
(22) is folded back to the outer layer side and laminated on the folded portion
Laminate the other end of the component material
Of heat-sealed polyester resin layers (16)
Liquid paper container (2 ) having a diprotection structure (21)
0), wherein the innermost polyester resin layer is
As a glycol component, 1,4-butanediol is a main component, and as an acid component, HO ₂ C- (A) —CO ₂ H (A
Represents a straight-chain or branched alkyl group having 3 or more carbon atoms in a straight-chain portion), and a polyester resin containing at least 20 mol% of an aliphatic dicarboxylic acid represented by the following formula: This is a liquid paper container in which a strong adhesive strength can be obtained between the resins of the innermost layer of the edge protection structure. In addition, as shown in FIG. 6, the second present invention further includes, adjacent to the outermost layer of the innermost polyester resin layer (56) of the laminated constituent material of the first invention,
A liquid paper container having good drop strength and impact resistance, wherein a laminated material (50) obtained by laminating a polyester resin layer (57) containing 1,4-butanediol as a main component as a glycol component is used. It is.

[0006] The above glycol component is 1,4
-Butanediol as a main component and HO ₂ C as an acid component
-(A) -CO ₂ H (A is a straight-chain moiety having 3 carbon atoms.
A polyester resin containing at least 20 mol% of an aliphatic dicarboxylic acid represented by the above-mentioned linear or branched alkyl group) is a resin having a good seal strength with a frame. Is described.

As shown in FIG. 2, the folded structure of the end of the laminated material of the liquid paper container according to the present invention prevents the contents from directly contacting the cut surface (22) of the end of the laminated material. Overlapping portion (23) of innermost resin (16)
Is provided with an edge protection structure (21) which is firmly heat-sealed by a frame seal.

The thickness of the frame-adhesive polyester-based resin layer according to the present invention is arbitrary, but is preferably 10 μm to 80 μm in consideration of the protection of the contents, the frame adhesiveness and the cost.
The range of μm is preferred.

The laminated constituent materials used in the liquid paper container of the present invention include, besides a paper layer as a base layer, a polyolefin layer (mainly a polyethylene layer) as an outermost layer, and a frame adhesive polyester resin layer as an innermost layer, Dry thermoplastic resin layers such as polyethylene, polypropylene, saponified ethylene-vinyl acetate copolymer, vinylidene chloride, and polyethylene terephthalate, metal foil layers such as aluminum, and inorganic vapor-deposited film layers according to the purpose of the container. Lamination is performed by a lamination method, a wet lamination method, an extrusion lamination method, or the like.

[0010]

【Example】

<Example 1> First, a basis weight of 230 g / m ² was used in order to produce the laminated constituent material of the liquid paper container of the present example shown in FIG.
And an aluminum foil having a thickness of 7 μm are laminated with an polyethylene having a thickness of 8 μm by an extrusion lamination method, and a polyethylene having a thickness of 20 μm is laminated on the paper surface by an extrusion lamination method.
A 12 μm-thick polyethylene terephthalate film and a 50 μm-thick frame-adhesive polyester resin film are sequentially laminated on the aluminum foil surface by a dry lamination method. [Outside] polyethylene layer (11) /
Paper layer (12) / 8 μm polyethylene layer (13) / aluminum foil layer (14) / polyethylene terephthalate (1
5) / Frame-adhesive polyester resin layer (16)
[Inside] Six-layer laminated constituent material (10) was produced. Characters and pictures were printed on the outermost polyethylene layer surface by gravure printing. Further, the innermost layer of the frame adhesive polyester resin has a composition ratio of an aliphatic component to an aromatic component of an acid component and 1,4-
Laminated constituent materials were produced using several kinds of resins having different composition ratios of butanediol and ethylene glycol.

Next, blanks are produced by punching and crease-making the various laminated constituent materials produced by a punching machine, and the end faces of these blanks are turned back to produce sleeves by frame sealing. (FT-B3 / 3000, manufactured by Osaka Koki Co., Ltd.) to form a container, fill (juice), seal, and form a 300 ml brick-shaped liquid paper container (20) having a flat top (25) shown in FIG. ) Was prepared. The edge of the laminated constituent material on the inner surface of the back panel (26) has an edge protection structure so as not to come into direct contact with the contents by the folded structure shown in FIG.

In order to evaluate the above-mentioned various types of liquid paper containers manufactured, the juice of the contents is discharged, the container is torn, and the innermost layer of the folded structure at the end of the laminated material is bonded by the gas frame. Was examined. As shown in Table 1, the composition ratio of the aliphatic dicarboxylic acid as the acid component of the frame adhesive polyester resin was 20 m, as shown in Table 1.
ol% or more, a sufficiently effective adhesive strength can be obtained,
If it was less than 20 mol%, sufficient adhesive strength could not be obtained. Further, even when the composition ratio of the aliphatic dicarboxylic acid of the acid component is 20 mol% or more, 1,
When 4-butanediol was not the main component (50 mol% or more), sufficient adhesive strength could not be obtained. further,
Various liquid papers in which 1,4-butanediol is used as a glycol component as a main component (50 mol% or more) and a composition ratio of an aliphatic dicarboxylic acid as an acid component is 20 mol% or more as a frame adhesive polyester resin as an innermost layer. The container was subjected to a content storage test for 6 months. As a result, there was no problem that the odor of the frame-adhesive polyester resin was transferred to the juice or that limonene of the juice was adsorbed by the innermost frame-adhesive polyester resin.

[0013]

[Table 1]

<Embodiment 2> First, the present embodiment shown in FIG.
Of the liquid paper container
As in Example 1, basis weight 230 g / m^TwoPaperboard and 7μm thick
Extrusion lamination with luminium foil
With 8μm thick polyethylene and the paper
20μm thick polyethylene on the surface
Laminated by the termination method and aluminum foil surface
Has a 12μm thick polyethylene terephthalate film
And 25μm thick polyester resin film and 25μm
Thick frame adhesive polyester resin film
Laminate in order by the lamination method
Polyethylene layer (51) / Paper layer (52) / Polyethylene layer
(53) / Aluminum foil layer (54) / Polyethylene
Phthalate layer (55) / polyester resin layer (5
7) / Frame adhesive polyester resin layer (56)
[Inside] Seven layers of laminated constituent materials (50) were produced. What
Note that the polyester resin layer is as shown in Note 1 of Table 2.
In addition, there are six kinds of po
Each layered component material is made using
Made. The last of these six types of laminated constituent materials (AF configuration)
The outer polyethylene layer surface is coated by gravure printing.
Printed letters and pictures. Also, the innermost layer frame bonding
The acidic polyester resin contains an aromatic terephthalic acid component.
With a composition ratio of 70 mol% of acid and 30 mol% of aliphatic adipic acid,
The glycol component is of 1,4-butanediol.
Was. Further, apart from the present embodiment, the innermost layer was used for comparison.
Terephthalic acid as the acid component and ethylene as the glycol component
Using a commercially available polyester resin as glycol
[Outside] 20 μm thick polyethylene layer / 230 g / m^TwoPaper layer
/ 8 µm thick polyethylene layer / 7 µm thick aluminum foil /
12 μm thick polyethylene terephthalate layer / 50 μm thick
Laminate constituent material of commercial polyester resin layer [inside] (G
Structure) and conventional innermost layer using polyethylene [outside]
20 μm polyethylene layer / 230 g / m ^TwoPaper layer / 8μm
Polyethylene layer / 7 µm thick aluminum foil / 12 µm thick
Polyethylene terephthalate layer / 25 μm thick polyethylene
Two types of lamination with layer (inside) lamination constituent material (H configuration)
The constituent materials were produced.

Next, the eight kinds of laminated constituent materials (A
To H configuration) in the same manner as in Example 1, punching and scoring were performed by a punching machine to produce blanks, the end faces of these blanks were turned back to produce sleeves by frame sealing, and the sleeves were poured into a filling machine. Then, container molding, filling (water), and sealing were performed, and eight types of 200-ml brick-shaped liquid paper containers (20) each having a flat top portion shown in FIG. 5 were produced. The edge of the laminated constituent material on the inner surface of the back panel (26) has an edge protection structure by a folded structure so as not to come into direct contact with the contents, as in the first embodiment.

These eight types of liquid paper containers were subjected to a drop impact test in order to evaluate the physical properties. The method is a single drop test in which the number of times a water-filled container is dropped vertically from a height of 120 cm onto a concrete floor surface and the bag is broken, and a case in which 30 water-filled containers are contained From a height of 120 cm and continuously dropped five times on a concrete floor surface to determine the number of broken bags. The results are shown in Table 2. As shown in Table 2, the liquid paper container using the laminated component material of the A configuration of the present embodiment is different from the conventional container of the laminated component material (H configuration) using polyethylene for the innermost layer. The liquid paper container using the laminated component materials of the B and C configurations shows drop impact resistance that is comparable to that of the first embodiment.
It was determined that the liquid paper container using the laminated constituent materials of the F and G configurations could not be practically used in terms of drop impact strength.

[0017]

[Table 2]

[0018]

As shown in the above examples, 1,4,4 as a glycol component was added to the innermost polyester resin layer.
-Butanediol as a main component and HO ₂ C as an acid component
-(A) -CO ₂ H (A is a straight-chain moiety having 3 carbon atoms.
The liquid paper container of the present invention using a polyester resin (frame-adhesive polyester resin) containing at least 20 mol% of an aliphatic dicarboxylic acid represented by the above-mentioned linear or branched alkyl group) The innermost layer of the folded structure portion at the end of the laminated material is heat-sealed firmly by the gas frame, and as a result, the drop impact resistance of the container is the same as that of the conventional container made of laminated material using polyethylene for the innermost layer. Showed comparable strength to.

The liquid paper container of the present invention uses the above-mentioned specific polyester resin for the innermost layer,
In the content preservation test for 6 months, the content showed excellent content preservability with respect to the smell and taste of the content.

[Brief description of the drawings]

FIG. 1 is a sectional view of a laminated constituent material used for a liquid paper container according to a first embodiment of the present invention.

FIG. 2 is a partial cross-sectional view showing a structure (edge protection structure) of a seal portion at an end portion of a laminated material of the liquid paper container according to the first embodiment of the present invention.

FIG. 3 is a sectional view of a laminated constituent material of a conventional liquid paper container.

FIG. 4 is a partial cross-sectional view showing a structure (edge protection structure) of a seal portion at an end portion of a laminated constituent material of a conventional liquid paper container.

FIG. 5 is a liquid paper container having a flat top used in the embodiment.

FIG. 6 is a sectional view of a laminated constituent material used for a liquid paper container according to a second embodiment of the present invention.

[Explanation of symbols]

10,30,50 …… Laminated constituent material 11,13,31,33,36,51,53 …… Polyethylene layer 12,32,52 …… Paper layer 14,34,54 …… Aluminum foil layer 15,35, 55… Polyethylene terephthalate layer 16,56 …… Frame-adhesive polyester resin 20,40… Liquid paper container 21,41… Seal part (edge protection structure) at the end of the laminated material inside the container 22,42… … Cutting surface at the end of laminated material 23,43… Frame seal between innermost layers of resin 25… Planar top 26… Back panel 27… Bottom 57… Polyester resin layer

Continuation of the front page (56) References JP-A-1-192552 (JP, A) JP-A-1-257030 (JP, A)

Claims (2)

(57) [Claims] 1. A paper layer as a substrate layer, at least the outermost layer is a polyolefin layer, the laminated structure material innermost layer is made of a polyester resin layer used and one of the layered structure material
Fold one end to the outer layer side and laminate on the folded part
Laminate the other end of the component material
Edge heat-bonded polyester resin layers
A liquid paper container having a tect structure, wherein the innermost polyester resin layer contains 1,4-butanediol as a glycol component as a main component and H as an acid component.
Polyester containing at least 20 mol% of an aliphatic dicarboxylic acid represented by O ₂ C- (A) -CO ₂ H (A represents a linear or branched alkyl group having 3 or more carbon atoms in a linear portion) A liquid paper container using a base resin. 2. The method according to claim 1, wherein a polyester resin layer containing 1,4-butanediol as a main component as a glycol component is laminated adjacent to an outer side of the innermost polyester resin layer. The liquid paper container according to the above.