JP2000225655A - Method for bonding trunk part of container and container prepared by method for bonding trunk part - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make bonding only by flame processing when a laminated sheet wherein different thermoplastic resins are used for the outer layer and the inner layer is made into a paper container by skive hemming processing. SOLUTION: A half of the thickness of a laminated sheet 10 of the end part of the laminated sheet is eliminated by a definite length from the apex and the remaining part which is not eliminated is folded so as to make the eliminated face inside to form the first folded part 213 and a half of the thickness of the laminated sheet on the opposite side face of another end part to the eliminated face of one end part is eliminated by a specified length from the apex and the remaining part which is not eliminated is folded so as to make the eliminated face inside to form the second folded part 253. The first folded part 213 formed on one end part and the second folded part 253 formed on another end part are folded so as to bring the folded faces into contact with each other and are bonded together by heat fusion to cylindrically form them.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for thermally fusing a body of a laminated sheet for containers, and more particularly to a method for thermally fusing a body of a laminated sheet for containers having different thermoplastic resin layers in an inner layer and an outer layer. About.

[0002]

2. Description of the Related Art A paper is used as a base material, and an inner layer and an outer layer are made of a polyolefin resin having excellent heat sealability. For example, [outside of container] polyethylene / paperboard / polyethylene /
Paper containers made of a laminated material such as an aluminum foil / polyethylene terephthalate film / polyethylene [container inside] configuration are widely used as containers for filling juice, sake, and the like. In particular, for the contents that have a strong permeability such as sake, and the distribution period is long, if the paper end face is exposed on the inner surface of the container, the contents penetrate therefrom into the paper base material layer, and the strength of the container is reduced. First, one side of the laminated material body joint portion is removed from the paper layer by half the thickness of the laminated material by a predetermined length from the front end, and the outside is removed (skive) from the paper layer, and the remaining part that has been scraped is removed so that the cut surface is on the inside. In general, folding (hemming) is performed to protect the paper end face. Hereinafter, this processing is referred to as skive hemming processing.

[0003] The body of the laminated material subjected to skive hemming is joined by performing a frame treatment using a gas burner or the like from the folded inner layer surface portion to the outer layer surface portion, and further to the corresponding inner layer surface at the other end. In general, a similar flame treatment was performed to oxidize the surface of each polyolefin resin to introduce a polar group and then press-bond both.

[0004] However, polyolefin resins used for the inner and outer layers of a general liquid paper container are excellent in processability, but have an oxidizing odor of the resin due to the influence of heat at the time of film formation. It has a drawback of easily adsorbing flavors and flavors, and is particularly unsuitable for contents such as whiskey and mineral water, which value the taste.

[0005] On the other hand, a low-odor, low-adsorption polyester resin having low resin odor, low flavor adsorption, and heat sealability has been developed. By using this polyester resin on the inner surface of the container, for example, a paper container made of a laminated material such as [container outside] polyethylene / paperboard / polyethylene terephthalate film / silicon oxide vapor-deposited thin film / polyester resin [container inside] is formed. This has made it possible to use the liquid paper container for contents that emphasize taste, such as whiskey and mineral water.

However, contents having high permeability such as whiskey still require the above-mentioned skive hemming. At this time, both the polyester resin-based surface portion of the inner layer 11 and the polyolefin-based resin surface portion of the outer layer 12 that are folded back to the outer layer side are simultaneously thermally fused to the inner polyester resin surface at the other end. That is, the thermal fusion between different thermoplastic resins is very difficult in terms of constitution only by the frame treatment (see FIG. 3).

That is, even if the container is molded in such a state, for example, the polyolefin-based resin surface portion and the polyester resin-based surface portion (the portion shown in FIG. 3) are not thermally fused, so that the seal width is reduced. Problems such as poor drop strength and poor appearance due to peeling of the portion occur.

[0008] The polyester resin and the polyolefin resin are not simply fused by heat alone, but the surface of the polyolefin resin is subjected to a flame treatment using a gas burner or the like, and the surface of the polyolefin resin is oxidized to introduce a polar group. , And heat fusion with the polyester resin. On the other hand, regarding the thermal fusion between the polyester-based resins, when the surface is oxidized by the frame treatment, the thermal fusion is adversely affected.

[0009] Accordingly, we have conducted intensive research and have studied Japanese Unexamined Patent Publication No. 3-2.
No. 27620 discloses a method for heat-sealing a paper container having a skid hemming process, in which the inner layer is made of a polyester resin having a low odor and a low adsorption and the outer layer is made of a polyolefin resin, at the time of joining the body to a whiskey. Practical application as a container.

That is, the surface of the outer layer polyolefin resin at the end subjected to skive hemming is subjected to frame treatment,
Hot air treatment is performed on the inner layer polyester resin surface portion folded to the outer layer side, and at the same time, the corresponding inner layer polyester resin surface portion on the other end is hot air treated, and both surfaces are pressed against each other. And a method of joining the body of the liquid paper container by heat-sealing.

[0011]

As described above, when the surface of a polyester resin is oxidized by a frame treatment, the heat-fusibility between the polyester resins is impaired. Therefore, in the body joining method using the combined use of the frame and the hot air, it is important to adjust the position of the gas burner for performing the frame treatment.

In other words, if the frame treatment extends from the polyolefin resin surface to the polyester resin portion on the inner layer surface folded back to the outer layer side, the adhesion between the polyester resins becomes insufficient, leading to leakage of the contents. . Conversely, if the frame treatment is displaced from the joint to the opposite side, the adhesion between the polyolefin-based resin and the polyester-based resin becomes insufficient, leading to a reduction in container strength. Adjustment of the position of the gas burner or hot air nozzle by switching the container size or the like requires skill and time.

According to the present invention, when a laminated sheet using a different thermoplastic resin for the outer layer and the inner layer, such as a polyethylene resin for the outer layer and a polyester resin for the inner layer, is subjected to skive hemming processing into a paper container, only a frame treatment is used. It is an object of the present invention to provide a body joining method that enables joining.

[0014]

Means for Solving the Problems A first invention of the present invention is:
A container made of a laminated sheet using paper as a base material, an inner layer as a first thermoplastic resin, and an outer layer as a second thermoplastic resin, wherein the inner layer at one end of the laminated sheet and the outer layer at the other end are thermally fused. In the step of joining and bonding to form a cylindrical shape, one end of the laminated sheet is removed from the tip by a predetermined length, half of the thickness of the laminated sheet is removed, and the remaining part is not removed. To form a first folded portion,
At the other end, the surface opposite to the deleted surface of the one end is a predetermined length from the front end, half of the thickness of the laminated sheet is deleted, and the remaining surface is left without being deleted. Folded inward to form a second folded part, and the first folded part formed at one end and the second folded part formed at the other end are in contact with each other. A method for joining the body of a container, wherein the container is folded, joined by heat fusion, and formed into a cylindrical shape.

According to a second aspect of the present invention, in the first aspect, the first thermoplastic resin is a polyolefin resin and the second thermoplastic resin is a polyester resin. Is the way.

Furthermore, a third aspect of the present invention is a container manufactured by the method of joining a trunk portion according to the first aspect.

[0017]

As described above, according to the present invention, one end of the laminated sheet is removed from the tip by a predetermined length, and half of the thickness of the laminated sheet is deleted, and the remaining portion is not removed. To form a first folded portion, and the other end of the laminated sheet has a predetermined length from the end opposite to the deleted surface of the one end, and halves the thickness of the laminated sheet. The part that has been left undeleted is folded back so that the removed surface is on the inside, and a second folded part is formed. The first folded part formed at one end and the other part formed at the other end Since the folded surfaces of the second folded portion are bent so as to be in contact with each other, only the thermoplastic resin of the same quality is joined, and only the frame treatment is performed to heat-bond the inner layer at one end and the outer layer at the other end. It becomes possible.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to embodiments. FIGS. 1A and 1B show an example of a laminated sheet 10 used for a container produced by the container body joining method of the present invention, wherein FIG. 1A is a development explanatory view and FIG. 1B is a sectional explanatory view.

As shown in FIG. 1, the laminated sheet 10 has a layer structure in which paper is used as a base material, an inner layer 11 is made of a first thermoplastic resin, and an outer layer 12 is made of a second thermoplastic resin.

The first thermoplastic resin constituting the inner layer 11 includes low-density polyethylene, medium-density polyethylene, high-density polyethylene, ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, ethylene-methyl acrylate copolymer. Resins such as polymers, ethylene-α-olefin copolymers, and polypropylene can be used. In addition, the appropriate thickness is set to 20 to 1 to provide a certain amount of adhesive strength.
It is about 00 μm.

As the second thermoplastic resin constituting the outer layer 12, a resin equivalent to the resin constituting the first thermoplastic resin can be used. However, an appropriate thickness is required to be about 40 to 1000 μm so that the resin can be buried in the abutting portion between the top and the bottom when formed into a box shape.

Incidentally, if necessary, the first thermoplastic resin and the second thermoplastic resin may be the same type of resin.

The lamination sheet is formed into a tubular shape as follows (see FIG. 2). First, the first panel 21, the second panel 22, the third panel 2
3, for example, the inside of the end of the first panel 21 which is one end of the laminated sheet 10 on which the fourth panel 24 and the fifth panel (adhesive margin piece) 25 are formed, with a predetermined length from the front end, Half of the thickness of the laminated sheet is deleted (deleted portion 211), and the remaining portion 212 that is not deleted is turned back so that the deleted surface is on the inside, and the first folded portion 213 is formed.

At the same time, the other side of the fifth panel (adhesive margin piece) 25 on the side opposite to the deleted side of the end of the first panel 21 has a predetermined length from the front end, and is a laminated sheet. Is removed (deleted portion 251), and the remaining portion 252 that is not deleted is folded back so that the deleted surface is on the inside.
The second folded portion 253 is formed.

Next, the inner surface of the first folded portion 213 at the end of the first panel 21 and the second inner surface of the end of the fifth panel 25
The outer surface of the folded portion 253 is subjected to frame processing and heated, and the third panel 23 and the fourth panel 24, and the first panel 21 and the second panel 22 are respectively bent from bending lines. The first folded portion 21 of the first panel 21 is overlapped with the outer surface of the fifth panel 25.
When 3 is overlaid so as to be above the second folded portion 253 of the fifth panel 25, the end of the first panel and the end of the fifth panel are joined by heat fusion, and the laminated sheet is formed into a tubular shape. Is done.

The series of skive hemming operations, frame processing, and cylindrical processing can be easily performed by a dedicated processing machine.

[0027]

EXAMPLES Examples of the present invention will be described below more specifically. <Example 1> having a basis weight of 400 g / m ² acid paper / thickness 25μ
m: ethylene-methacrylic acid copolymer resin, Nuclell (trade name; manufactured by Du Pont-Mitsui Polychemical Co., Ltd.) / aluminum foil having a thickness of 9 μm / biaxially stretched polyethylene terephthalate film (PET) having a thickness of 12 μm
A 25 μm-thick polyolefin-based resin, Mirason 16 on the acid-resistant paper surface of a laminated sheet base material having a laminated structure of
A surface layer of P (trade name; manufactured by Mitsui Chemicals, Inc.) is formed to form an inner layer 11. Then, on the PET surface,
The polyester resin film of Example 1 was laminated to form the outer layer 12, and a packaging material for a laminated sheet used in the present invention was obtained.

As shown in FIG. 1, a laminated sheet in which a first panel 21, a second panel 22, a third panel 23, a fourth panel 24, and a fifth panel 25 are continuously provided from the packaging material via a folding line. 10 was produced. Note that the first panel side is made 8 mm longer than the conventional panel.

Next, the first panel 21 which is one end portion
The inside of the end (PET surface side) is 16 mm from the tip, and half of the thickness of the laminated sheet is deleted (deleted portion 21).
1) The part 212 left without being deleted is folded so that the deleted surface is on the inside, and the first folded part 213 having a length of 8 mm is formed.

At the same time, the surface (polyolefin-based resin surface) of the fifth panel (adhesive margin piece) 25, which is the other end, on the side opposite to the deleted surface of the end of the first panel 21 is moved from the front end by one.
With a length of 6 mm, a half of the thickness of the laminated sheet is deleted (deleted portion 251), and a portion 252 remaining without being deleted is folded back so that the deleted surface is on the inside, and a second folded back having a length of 8 mm is provided. A part 253 is formed.

Next, the inner surface of the first folded portion 213 at the end of the first panel 21 and the second surface of the end of the fifth panel 25
Approximately 20 m from the edge of the outer surface of the folded part 253
m and heated with a width of m, and the third panel 23
And the fourth panel 24, and the first panel 21 and the second panel 22 are each bent from a bending line, and the first folding of the first panel 21 is performed so that the inner surface of the first panel 21 overlaps the outer surface of the fifth panel 25. The first panel 213 is overlapped with the fifth panel 25 so that the first panel 213 is located above the second folded section 253 of the fifth panel 25,
When pressure is applied by a rubber roll from the panel side, the end of the first panel and the end of the fifth panel are joined, and the laminated sheet is formed into a cylindrical shape (FIGS. 2A, 2B, and 2C). ,
(D), (e))).

[0032]

As described above, according to the present invention, the same resin is welded to each other, so that the sealing strength is increased, and thus the resistance such as drop strength is improved. Even if the resin on the front side and the resin on the inside are different, they can be formed into a cylindrical body if they have sealing properties. Since the sealant can be changed in various ways such as polyester and polypropylene, a sealant suitable for the contents can be relatively easily developed. Since the skive hemming process is also applied to the outside of the cylindrical body, it is possible to manufacture a container having improved water resistance. Since the main body is only slightly lengthened in the lateral direction without using a component such as a tape, it can be manufactured relatively inexpensively.

[Brief description of the drawings]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows an embodiment of a laminated sheet used for a container produced by the method of joining containers of a container of the present invention, (a) is a development explanatory view, and (b) is a sectional explanatory view.

FIGS. 2A and 2B are explanatory views showing a procedure of skiving hemming of the laminated sheet, in which FIG. 2A is a cross-sectional explanatory view showing one skived state, and FIG. It is sectional explanatory drawing which shows the state (hemmed), (c) is sectional explanatory drawing which shows the state which stuck the 1st folded part and the 2nd folded part.
(D) is a cross-sectional explanatory view showing another skived state, and (e) is a cross-sectional explanatory view showing a state in which the remaining skived part is folded back (hemmed).

FIG. 3 is an explanatory cross-sectional view showing a state in which one end and another end of a laminated sheet subjected to a conventional skive hemming process are bonded to each other.

[Explanation of symbols]

 10 laminated sheet 11 inner layer 12 outer layer 21 first panel 22 second panel 23 third panel 24 fourth panel 25 fifth panel 211 one end Deletion surface 212 {Part left at one end without being deleted 213} First folded part 251 {Deleted surface at the other end 252} Left without deletion at the other end 253２５2nd folded part

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification FI theme coat ゛ (Reference) B29K 67:00 101: 12 B29L 22:00 F-term (Reference) 3E060 AB04 BC01 DA20 DA23 EA03 3E075 BA02 CA01 DB35 DD13 DD32. TH06 TH17 TH18 TH21 TN24 TQ03 TQ13

Claims (3)

[Claims] (1) a paper-based material, wherein the inner layer is a first thermoplastic resin;
A container formed of a laminated sheet having an outer layer of a second thermoplastic resin, wherein an inner layer at one end and an outer layer at the other end are joined by heat fusion to form a cylindrical shape; One end of the sheet is a predetermined length from the front end, a half of the thickness of the laminated sheet is deleted, and the remaining part without being deleted is folded back so that the deleted surface is on the inside, to form a first folded part, At the other end, the surface opposite to the deleted surface of the one end is a predetermined length from the front end, half of the thickness of the laminated sheet is deleted, and the remaining surface is left without being deleted. Folded inward to form a second folded portion, and the first folded portion formed at one end and the second folded portion formed at the other end come into contact with each other with their folded surfaces in contact with each other Folded and joined by heat fusion to form a tube A method for joining a body of a container, characterized by comprising: 2. The method according to claim 1, wherein the first thermoplastic resin is a polyolefin resin and the second thermoplastic resin is a polyester resin. 3. A container manufactured by the method of joining body parts according to claim 1.