JP4202089B2 - Multilayer tube - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a multilayer tube composed of a laminate in which a plurality of layers are stacked, and is intended to reduce the oxygen concentration inside the tube and maintain the quality of the contents over a long period of time. .
[0002]
[Prior art]
Synthetic resin tubes can be mass-produced compared to metal cans and glass containers and can be reduced in cost, and in addition to this, handling is relatively easy. It is used for all purposes as a container for cosmetics, a seasoning, or a container for detergents.
[0003]
By the way, metal containers and glass containers pass through the wall surface of the container, and oxygen does not permeate into the interior at all. There is a problem of affecting the quality of.
[0004]
In addition, there is a concern that the contents of this type of container may be oxidized by oxygen present in the internal space of the container, and a solution to this problem is also desired.
[0005]
As a prior art regarding this point, a plastic multilayer container having a laminated structure in which a gas barrier thermoplastic resin containing an oxygen scavenger is provided as an intermediate layer is known (for example, see Patent Document 1).
[0006]
[Patent Document 1]
Japanese Patent Publication No. 4-608256.
[0007]
[Problems to be solved by the invention]
The object of the present invention is to propose a novel multilayer tube that reliably prevents oxygen from entering from the outside, reduces the influence of oxygen present in the internal space of the container, and maintains stable quality over a long period of time. is there.
[0008]
[Means for Solving the Problems]
The present invention is a tube composed of a head having a spout for contents and a body part connected to the head and shaped at the tail end in a fishtail shape,
At least the body part is composed of a laminated structure in which a resin layer heat-sealable from the inside to the outside, an oxygen absorption layer, an Al layer, and a polyethylene resin layer are sequentially stacked.
A laminated structure in which the head is formed by sequentially superposing a polyethylene resin layer, an EVOH layer and a polyethylene resin layer, or a polyethylene resin layer, an oxygen absorbing layer, an EVOH layer and a polyethylene resin layer from the inside to the outside. The oxygen absorption layer is preferably composed of a polyethylene resin layer containing an iron oxygen absorber and a copper oxygen absorber.
[0009]
The head can be a laminated structure in which an aluminum cup is inserted and fixed inside.
[0010]
Hereinafter, the present invention will be described more specifically with reference to the drawings.
[0011]
FIG. 1 shows the appearance of a multilayer tube according to the present invention showing a laminated structure of four layers as an example, and the cross section of its trunk.
[0012]
The tube in the figure is composed of a head 1 having a spout for contents and a body portion 2 connected to the head 1 and having a tail end formed into a fishtail shape.
[0013]
The body portion 2 is, for example, a laminated structure in which at least a linear low density polyethylene resin layer 2a, an oxygen absorption layer 2b, an Al layer 2c, and a low density polyethylene resin layer 2d are sequentially stacked from the inside to the outside. It is made up of. For the Al layer 2c, an Al foil of polyethylene resin / Al / polyethylene resin is used. Further, the low density polyethylene resin 2d constituting the outermost layer described above is not limited to a single layer configuration, and for example, has a multilayer configuration such as polyethylene adhesive resin / EVOH / polyethylene adhesive resin. The configuration can be arbitrarily selected.
[0014]
In the tube configured as described above, gas components such as oxygen entering through the low density polyethylene resin layer 2d are effectively blocked by the Al layer 2c, while oxygen existing in the space in the tube is absorbed by the oxygen absorbing layer 2b. Therefore, the space is kept in a low oxygen state.
[0015]
The oxygen absorption layer 2 can be composed of a polyethylene resin containing an iron oxygen absorber or a copper oxygen absorber.
[0016]
Oxygen absorbers are generally reducible and are themselves oxidized by oxygen, and this oxidation reaction is activated by capturing moisture contained in the contents.
[0017]
Specific examples of oxygen absorbers include reducing metal powders such as reducing iron, reducing zinc, and reducing tin powder, iron carbide, silicon iron, iron carbonyl, and ferrous hydroxide. Reducing metal compounds mainly composed of those can be used, and these are optionally alkali metal, alkaline earth metal hydroxide, carbonate, sulfite, thiosulfate, and tertiary phosphate. , Secondary phosphates, organic acid salts, halides, activated carbon, activated lumina, activated clay and the like can also be combined.
[0018]
In addition, a polymer compound having a polyhydric phenol such as a polyhydric phenol-containing phenol / aldehyde resin in the skeleton can be used as the oxygen absorbent.
[0019]
These oxygen absorbents desirably have an average particle size of 100 μm or less, more preferably 50 μm or less.
[0020]
Other oxygen absorbers include MXD + Co and vitamins (ascorbic acid (vitamin C), vitamin B or vitamin E compounds), Group IV metals such as tin, titanium, zirconium, etc., and V, such as vanadium. Metal components of Group VII such as genus and manganese can be used, and the oxygen absorbent used is not limited to those listed here.
[0021]
The resin layer located on the innermost side of the body may be heat-sealable, and other than linear low-density polyethylene resin (LLDPE), low-density polyethylene (LDPE), medium-density polyethylene (MDPE), high Density polyethylene (HDPE), adhesive resin, PP, PET resin, EVOH resin, PAN resin, and the like can be used.
[0022]
As the P seal that seals the spout of the head, a laminated structure in which a polyethylene resin layer, an oxygen absorption layer, an Al layer (or EVOH layer), and a PET resin layer are laminated is applicable.
[0023]
【Example】
Using tubes 1 to 3 having the laminated structure shown below, a small amount of water was put in each tube, and then sealed and maintained at a temperature of 23 ° C. to investigate the change in oxygen concentration in the tube. It was. The results are shown in comparison with FIG.
[0024]
Tube 1 (conforming example)
Body: LLDPE (thickness 30 μm) + oxygen absorption layer (50 μm thick polyethylene resin containing 5% reducing iron powder as Fe-based oxygen absorber) + Al layer (thickness 12 μm) + polyethylene resin (thickness) 150 μm) + EVOH (thickness 30 μm) + polyethylene resin (thickness 150 μm)
Head: Polyethylene adhesive resin (thickness 200 μm) + EVOH (thickness 30 μm) + polyethylene adhesive resin (thickness 200 μm)
Tube 2 (Comparative Example 1)
Body: LLDPE (thickness 30 μm) + Al layer (thickness 12 μm / polyethylene resin (thickness 15 μm) / EVOH (thickness 30 μm) / polyethylene resin (thickness 150 μm)
Head: Polyethylene resin (thickness 200 μm) + EVOH (thickness 30 μm) / polyethylene resin (thickness 200 μm)
Tube 3 (Comparative Example 2)
Body: LLDPE (thickness 30 μm) / oxygen absorbing layer (50 μm thick polyethylene resin containing 5% reducing iron powder as Fe-based oxygen absorber) / polyethylene resin (thickness 350 μm)
Head: Polyethylene resin (thickness 200 μm) + EVOH (thickness 30 μm) / polyethylene resin (thickness 200 μm)
[0025]
As is clear from FIG. 2, in Comparative Example 1, the oxygen concentration in the tube was 20% or more, and it was not different from the oxygen concentration in the atmosphere. The tube according to the present invention (conforming example) does not have the ability to reduce the oxygen concentration for a month, but the oxygen concentration in the tube is 2% or less even if stored for one month at a temperature of 23 ° C. It was confirmed that the hypoxic state can be stably maintained.
[0026]
Note that the layer structure of the head in the present invention may be a single layer or may be a laminated structure as in the above-described embodiment. In addition, in the case of a laminated structure, a laminated structure in which an aluminum cup is inserted and fixed inside, or a polyethylene resin layer, an EVOH layer, a polyethylene resin layer, or a polyethylene resin layer is directed from the inside to the outside. In addition, a laminated structure in which an oxygen absorbing layer, an EVOH layer, and a polyethylene resin layer are sequentially stacked is used, or a laminated structure that has both configurations is used.
[0027]
【The invention's effect】
According to the present invention, gas can be prevented from entering from the outside and the inside of the tube can be maintained in a low oxygen state, so that the contents are not oxidized and accompanied by quality deterioration.
[Brief description of the drawings]
FIG. 1 shows an embodiment of a multilayer tube according to the present invention.
FIG. 2 is a graph in which changes in oxygen concentration in a tube are investigated.
[Explanation of symbols]
1 Head 2 Body 2a Linear low density polyethylene resin layer 2b Oxygen absorption layer 2c Al layer 2d Low density polyethylene resin layer

Claims (2)

A tube comprising a head having a spout for contents and a body part connected to the head and shaped at its tail end in a fishtail shape,
At least the body part is composed of a laminated structure in which a resin layer capable of heel sheet, an oxygen absorption layer, an Al layer, and a polyethylene resin layer are sequentially stacked from the inside to the outside,
A laminated structure in which the head is formed by sequentially superposing a polyethylene resin layer, an EVOH layer and a polyethylene resin layer, or a polyethylene resin layer, an oxygen absorbing layer, an EVOH layer and a polyethylene resin layer from the inside to the outside. multilayer tube characterized in that it consists.   The multilayer tube according to claim 1, wherein the oxygen absorbing layer is made of a polyethylene resin layer containing an iron oxygen absorber and a copper oxygen absorber.

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