JP2016198911A - Multilayer structural body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multilayer structural body which at least partially has a multilayer structure containing an inner layer, an outer layer and a barrier layer, and can prevent delamination at a higher level.SOLUTION: There is provided a multilayer structural body at least partially having a multilayer structure containing an inner layer, an outer layer and at least one barrier layer positioned between the inner layer and the outer layer, where the inner layer and the outer layer are each independently formed of a resin composition (C) containing 94-99.9 mass% of polyester (A) containing a dicarboxylic acid unit containing 80 mol% or more of a terephthalic acid unit and a diol unit containing 80 mol% or more of an ethylene glycol unit and 0.1-6 mass% of polyamide (B) containing a diamine unit containing 70 mol% or more of a m-xylylenediamine unit and a dicarboxylic acid unit, and the barrier layer is formed of a resin composition (D) containing 1-40 mass% of the polyester (A) and 60-99 mass% of the polyamide (B).SELECTED DRAWING: Figure 1

Description

  The present invention relates to a multilayer structure, and more particularly to a multilayer structure suitably used as a container for packaging a substance that hates oxygen, such as beverages, foods, cosmetics and pharmaceuticals, or a preform thereof.

  Various plastic containers are used as containers for packaging beverages, foods, cosmetics, pharmaceuticals, and the like. Plastic containers are superior in terms of light weight, high transparency, freedom of design, safety, etc., but oxygen and other gases pass through the walls of the container compared to metal cans and glass bottles. Since it is easy to permeate | transmit, it becomes an important subject to prevent the deterioration of the content by the oxygen from the outside of a container, and the fall of a taste or fragrance.

Conventionally, a method has been known in which a barrel portion of a plastic container has a multilayer structure and, for example, a barrier layer made of a metaxylylene group-containing polyamide is provided between surface layers made of polyester such as polyethylene terephthalate to prevent oxygen from entering the inside of the container. ing. However, this method is excellent in that high barrier properties and transparency can be obtained, but it tends to cause delamination due to dropping or impact from the outside, resulting in deterioration of barrier properties and deterioration of appearance. It was a problem.
In order to solve the above problems, there has been proposed a method for preventing delamination by blending and using polyethylene terephthalate in addition to a metaxylylene group-containing polyamide in the barrier layer (Japanese Patent Laid-Open No. 2007-223667 (Patent Document 1)). No. 5,387,054 (Patent Document 2), Japanese Patent Laid-Open No. 58-197050 (Patent Document 3), etc.). This method is excellent in that the barrier property is not significantly impaired even if a small amount of polyethylene terephthalate is blended with a metaxylylene group-containing polyamide, but if the impact from the outside is large, delamination may not be sufficiently prevented. There was a problem that handling was difficult.
In addition, for the purpose of improving barrier properties, or for the purpose of reducing aldehydes, which are trace amounts of impurities contained in polyester, a method of blending a metaxylylene group-containing polyamide on the surface layer has been proposed, Prevention of delamination has not been studied (Japanese Patent Laid-Open No. 2000-168017 (Patent Document 4), Japanese Patent Laid-Open No. 2006-290436 (Patent Document 5)).

JP 2007-223667 A Japanese Patent No. 5387054 JP-A-58-197050 JP 2000-168017 A JP 2006-290436 A

  Under such circumstances, there is a need to provide a multilayer structure that has a multilayer structure including an inner layer, an outer layer, and a barrier layer at least in part and can prevent delamination at a higher level.

  As a result of intensive investigations in view of the above problems, the present inventors have used, as a barrier layer, a polyester blended with a predetermined amount ratio in addition to a metaxylylene group-containing polyamide, as well as an inner layer and an outer layer which are surface layers. By using a blend of a metaxylylene group-containing polyamide in addition to the polyester at a predetermined ratio, the interlayer adhesion can be improved as compared to the case of using a blend of a metaxylylene group-containing polyamide and a polyester only in the barrier layer or only in the surface layer. The present invention was found to be dramatically improved, and the present invention was completed based on these findings.

That is, this invention provides the multilayer structure shown below.
[1] A multilayer structure having at least a part of a multilayer structure including an inner layer, an outer layer, and at least one barrier layer positioned between the inner layer and the outer layer,
The inner layer and the outer layer are each independently 94 to 99.9% by mass of polyester (A) containing a dicarboxylic acid unit containing 80 mol% or more of terephthalic acid units and a diol unit containing 80 mol% or more of ethylene glycol units, and And a resin composition (C) containing 0.1 to 6% by mass of a polyamide (B) containing a diamine unit containing 70% by mole or more of a metaxylylenediamine unit and a dicarboxylic acid unit,
The barrier layer contains 1 to 40% by mass of a polyester (A) containing a dicarboxylic acid unit containing 80 mol% or more of terephthalic acid units and a diol unit containing 80 mol% or more of ethylene glycol units, and 70 metaxylylenediamine units. The multilayer structure which consists of a resin composition (D) containing 60-99 mass% of polyamides (B) containing the diamine unit and dicarboxylic acid unit which contain more than mol%.
[2] The multilayer according to [1], wherein the polyamide (B) is a polyamide containing a diamine unit containing 70 mol% or more of metaxylylenediamine units and a dicarboxylic acid unit containing 70 mol% or more of adipic acid units. Structure.
[3] Polyamide (B) includes a diamine unit containing 70 mol% or more of metaxylylenediamine units, and a dicarboxylic acid unit containing 70 to 99 mol% of adipic acid units and 1 to 30 mol% of isophthalic acid units. The multilayer structure according to [1] or [2], which is a polyamide containing.
[4] Diol whose polyester (A) contains 80 to 99.9 mol% of terephthalic acid units and 0.1 to 10 mol% of metal sulfoisophthalic acid units and 80 mol% or more of ethylene glycol units The multilayer structure according to any one of [1] to [3], which is a polyester including a unit.
[5] The multilayer structure according to any one of [1] to [4], which has at least a part of a three-layer structure including an inner layer / barrier layer / outer layer.
[6] It has a five-layer structure consisting of an inner layer / barrier layer / intermediate layer / barrier layer / outer layer at least in part,
94-99.9 mass% of polyester (A) in which an intermediate | middle layer contains the dicarboxylic acid unit which contains 80 mol% or more of terephthalic acid units, and the diol unit which contains 80 mol% or more of ethylene glycol units, and a metaxylylene diamine unit [1] to [4], comprising a resin composition (E) containing 0.1 to 6% by mass of a polyamide (B) containing 70 mol% or more of a diamine unit and a dicarboxylic acid unit. The multilayer structure described.
[7] The multilayer structure according to any one of [1] to [6], which is a preform.
[8] The multilayer structure according to any one of [1] to [6], which is a container obtained by blow molding a preform by a hot parison method or a cold parison method.
[9] The multilayer structure according to [7] or [8], which has a multilayer structure at least in the body portion.

  According to a preferred embodiment of the present invention, it has a high gas barrier property, does not easily cause delamination against a drop or an external impact, is easy to handle, changes in content due to oxygen, and deteriorates taste and flavor. A multilayer structure that can be effectively prevented can be provided. The multilayer structure of the present invention can be suitably used as a container for packaging a substance that hates oxygen, such as beverages, foods, cosmetics and pharmaceuticals, or a preform thereof.

It is a general | schematic fragmentary sectional view which shows an example of the 3 layer structure which the multilayer structure of this invention has. It is a general | schematic fragmentary sectional view which shows an example of the 5 layer structure which the multilayer structure of this invention has. It is a schematic sectional drawing which shows the preform which is an example of the multilayer structure of this invention. It is a schematic sectional drawing which shows the bottle which is an example of the multilayer structure of this invention.

Hereinafter, the multilayer structure of the present invention will be specifically described.
The multilayer structure of the present invention is a multilayer structure having at least a part of a multilayer structure including an inner layer, an outer layer, and at least one barrier layer positioned between the inner layer and the outer layer,
The inner layer and the outer layer are each independently 94 to 99.9% by mass of polyester (A) containing a dicarboxylic acid unit containing 80 mol% or more of terephthalic acid units and a diol unit containing 80 mol% or more of ethylene glycol units, and And a resin composition (C) containing 0.1 to 6% by mass of a polyamide (B) containing a diamine unit containing 70% by mole or more of a metaxylylenediamine unit and a dicarboxylic acid unit,
The barrier layer contains 1 to 40% by mass of a polyester (A) containing a dicarboxylic acid unit containing 80 mol% or more of terephthalic acid units and a diol unit containing 80 mol% or more of ethylene glycol units, and 70 metaxylylenediamine units. It is characterized by comprising a resin composition (D) containing 60 to 99% by mass of a polyamide (B) containing a diamine unit containing at least mol% and a dicarboxylic acid unit.

  In the present invention, polyester (A) and polyamide (B) having a predetermined structural unit are blended and used for each layer of the inner layer, the outer layer, and the barrier layer located between the inner layer and the outer layer. By adjusting the amount ratio of the polyester (A) and the polyamide (B) within a predetermined range, the interlayer adhesion is enhanced while maintaining a high barrier property. Even if a barrier resin such as a metaxylylene group-containing polyamide is added to the barrier layer to increase the barrier property, if the delamination occurs due to a drop or impact from the outside, the barrier property is reduced, and the content is reduced. Not only can it not be stored stably, it is also undesirable in appearance. Therefore, in the present invention, it is easy to handle while maintaining a high barrier property by making it difficult to cause delamination against a drop or external impact, and the content is deteriorated by oxygen and deteriorated in taste and flavor. It is an object of the present invention to provide a multilayer structure that can effectively prevent the above. Hereinafter, the inner layer, the outer layer, and the barrier layer constituting the multilayer structure of the multilayer structure of the present invention will be specifically described.

1. Inner layer and outer layer
In the multilayer structure of the present invention, the inner layer and the outer layer are layers that hold the contents safely and stably, and have a role of protecting the barrier layer. Each of the inner layer and the outer layer used in the multilayer structure of the present invention may be one layer or two or more layers.

  In the present invention, the inner layer and the outer layer are each independently a polyester (A) 94 to 99.9 containing a dicarboxylic acid unit containing 80 mol% or more of terephthalic acid units and a diol unit containing 80 mol% or more of ethylene glycol units. It is comprised from the resin composition (C) containing 0.1-6 mass% of polyamide (B) containing the diamine unit and dicarboxylic acid unit which contain 70 mass% or more of metaxylylene diamine units by mass%. Hereinafter, each component of the resin composition constituting each layer of the inner layer and the outer layer will be described.

[Polyester (A)]
The polyester (A) is a polyester containing a dicarboxylic acid unit containing 80 mol% or more of terephthalic acid units and a diol unit containing 80 mol% or more of ethylene glycol units, and the dicarboxylic acid is contained in the repeating structural unit of the polymer main chain. It has an ester bond {—C (═O) O—} composed of a unit and the diol unit.

The dicarboxylic acid unit constituting the polyester (A) contains terephthalic acid units in an amount of 80 mol% or more, preferably 85 mol% or more, more preferably 87 mol% or more, and further preferably 90 mol% or more. By including the terephthalic acid unit in the above-mentioned quantitative ratio, the polyester (A) is unlikely to be amorphous, and heat shrinkage is difficult when a multilayer structure is formed, and the heat resistance is good. The upper limit of the terephthalic acid unit contained in the dicarboxylic acid unit is not particularly limited, but is preferably 99.9 mol% or less, and more preferably 95 mol% or less.
Dicarboxylic acids constituting dicarboxylic acid units other than terephthalic acid units include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, decanedicarboxylic acid, dodecanedicarboxylic acid, Tetradecanedicarboxylic acid, hexadecanedicarboxylic acid, 3-cyclobutanedicarboxylic acid, 1,3-cyclopentanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 2,5 -Saturated aliphatic dicarboxylic acid exemplified by norbornane dicarboxylic acid, tricyclodecane dicarboxylic acid, dimer acid or the like, or ester-forming derivatives thereof, unsaturated aliphatic dicarboxylic acid exemplified by fumaric acid, maleic acid, itaconic acid, etc. Or these Ester-forming derivatives; orthophthalic acid, isophthalic acid, diphenic acid, 1,3-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 2,7- Naphthalene dicarboxylic acid, biphenyl ketone dicarboxylic acid, 4,4′-biphenyl dicarboxylic acid, 4,4′-biphenyl sulfone dicarboxylic acid, 4,4′-biphenyl ether dicarboxylic acid, 1,2-bis (phenoxy) ethane-p, Examples thereof include aromatic dicarboxylic acids exemplified by p′-dicarboxylic acid, pamoic acid, anthracene dicarboxylic acid and the like, and ester-forming derivatives thereof.
Among these, in particular, the use of aromatic dicarboxylic acids such as isophthalic acid, orthophthalic acid, naphthalenedicarboxylic acid, 4,4′-biphenyldicarboxylic acid, or ester-forming derivatives thereof can improve the physical properties of the resulting polyester. This is preferable.
Moreover, the polyester containing the structural unit derived from an alicyclic bifunctional compound such as 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, and 1,4-cyclohexanedicarboxylic acid is easy to produce, Moreover, the drop impact strength and transparency of the multilayer structure can be further improved, which is preferable. Among these, it is preferable to use 1,4-cyclohexanedicarboxylic acid which is easily available and has high drop impact strength.

The diol unit constituting the polyester (A) contains 80 mol% or more, preferably 85 mol% or more, more preferably 88 mol% or more, and still more preferably 90 mol% or more, of ethylene glycol units. By including the ethylene glycol unit in the above-mentioned quantitative ratio, the crystallinity is excellent, and the gas barrier property and the strength for retaining the contents can be obtained. The upper limit of the ethylene glycol unit contained in the diol unit is not particularly limited and is, for example, 99 mol%.
When a diol unit other than an ethylene glycol unit is included, the diol constituting the diol unit includes 1,2-propylene glycol, 1,3-propylene glycol, diethylene glycol, triethylene glycol, 1,2-butylene glycol, 1, 3-butylene glycol, 2,3-butylene glycol, 1,4-butylene glycol, 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, methylpentanediol, 1,2-cyclohexanediol, 1, 3-cyclohexanediol, 1,4-cyclohexanediol, 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, 1,4-cyclohexanediethanol, norbornene di Illustrative examples include butanol, tricyclodecane dimethanol, 1,10-decane glycol, 2-butene-1,4-diol, 1,12-dodecane diol, polyethylene glycol, polytrimethylene glycol, polytetramethylene glycol, and the like. Aliphatic glycol; hydroquinone, 4,4′-dihydroxybisphenol, 1,4-bis (β-hydroxyethoxy) benzene, 1,4-bis (β-hydroxyethoxyphenyl) sulfone, bis (p-hydroxyphenyl) ) Ether, bis (p-hydroxyphenyl) sulfone, bis (p-hydroxyphenyl) methane, 1,2-bis (p-hydroxyphenyl) ethane, bisphenol A, bisphenol C, 2,5-naphthalenediol, isosorbide, 2 , 2,4,4-Tetrame Examples thereof include aromatic glycols exemplified by til-1,3-cyclobutanediol and glycols obtained by adding ethylene oxide to these glycols.
Among these, 1,3-propylene glycol, 1,4-butylene glycol, 1,4-cyclohexanedimethanol and neopentyl glycol are particularly preferably used.

In one embodiment of the present invention, the copolymer component other than terephthalic acid / ethylene glycol contained in the polyester (A) includes isophthalic acid, orthophthalic acid, 2,6-naphthalenedicarboxylic acid, and 4,4′-biphenyldicarboxylic acid. At least one selected from the group consisting of diethylene glycol, neopentyl glycol, 1,4-cyclohexanedimethanol, 1,2-propanediol, 1,3-propanediol and 2-methyl-1,3-propanediol. It is preferable for achieving both transparency and moldability. In particular, at least one selected from the group consisting of isophthalic acid, 2,6-naphthalenedicarboxylic acid, neopentyl glycol and 1,4-cyclohexanedimethanol is more preferable.
Among these, a copolymer polyester containing a structural unit derived from isophthalic acid is excellent in moldability and is excellent in that whitening of a molded product is prevented by slowing down the crystallization rate. The proportion of the structural unit derived from isophthalic acid is preferably 1 to 10 mol%, more preferably 1 to 8 mol%, still more preferably 1 to 6 mol%, based on the total number of moles of dicarboxylic acid units.
In addition, the copolyester containing a structural unit derived from naphthalenedicarboxylic acid increases the glass transition point of the resin, improves heat resistance, absorbs ultraviolet rays, and therefore has a multilayer structure requiring resistance to ultraviolet rays. It is suitably used for production. The proportion of the structural unit derived from naphthalenedicarboxylic acid is preferably 0.1 to 15 mol%, more preferably 1.0 to 10 mol%, based on the total number of moles of dicarboxylic acid units. By setting it as said ratio, it becomes possible to protect appropriately the content accommodated in a multilayer structure from an ultraviolet-ray. As naphthalenedicarboxylic acid, a 2,6-naphthalenedicarboxylic acid component is preferable because it is easy to produce and economical.

  In one embodiment of the present invention, in particular, the composition of polyester (A) includes a combination of terephthalic acid / isophthalic acid // ethylene glycol, a combination of terephthalic acid // ethylene glycol / 1,4-cyclohexanedimethanol, terephthalic acid // The combination of ethylene glycol / neopentyl glycol is preferable for achieving both transparency and moldability. Needless to say, the polyester (A) may contain a small amount (5 mol% or less) of diethylene glycol produced by dimerization of ethylene glycol during the esterification (transesterification) reaction or polycondensation reaction.

Moreover, in one Embodiment of this invention, polyester (A) may also contain the structural unit derived from monofunctional compounds, such as monocarboxylic acid, monoalcohol, or these ester formation derivatives. Specific examples of these compounds include benzoic acid, o-methoxybenzoic acid, m-methoxybenzoic acid, p-methoxybenzoic acid, o-methylbenzoic acid, m-methylbenzoic acid, p-methylbenzoic acid, 2,3 -Dimethylbenzoic acid, 2,4-dimethylbenzoic acid, 2,5-dimethylbenzoic acid, 2,6-dimethylbenzoic acid, 3,4-dimethylbenzoic acid, 3,5-dimethylbenzoic acid, 2,4,6 -Trimethylbenzoic acid, 2,4,6-trimethoxybenzoic acid, 3,4,5-trimethoxybenzoic acid, 1-naphthoic acid, 2-naphthoic acid, 2-biphenylcarboxylic acid, 1-naphthalene acetic acid and 2-naphthalene acetic acid Aromatic monofunctional carboxylic acids such as propionic acid, butyric acid, n-octanoic acid, n-nonanoic acid, myristic acid, pentadecanoic acid, stearic acid, oleic acid, linoleic acid Aliphatic monocarboxylic acids such as linolenic acid; ester-forming derivatives of these monocarboxylic acids, aromatic alcohols such as benzyl alcohol, 2,5-dimethylbenzyl alcohol, 2-phenethyl alcohol, phenol, 1-naphthol and 2-naphthol Aliphatic or alicyclic such as butyl alcohol, hexyl alcohol, octyl alcohol, pentadecyl alcohol, stearyl alcohol, polyethylene glycol monoalkyl ether, polypropylene glycol monoalkyl ether, polytetramethylene glycol monoalkyl ether, oleyl alcohol and cyclododecanol And the formula monoalcohol.
Among these, benzoic acid, 2,4,6-trimethoxybenzoic acid, 2-naphthoic acid, stearic acid, and stearyl alcohol are preferable from the viewpoint of ease of polyester production and production cost thereof. The proportion of the structural unit derived from the monofunctional compound is 5% by mole or less, preferably 3% or less, more preferably 1% or less, based on the total number of moles of all the structural units of the polyester (A). The monofunctional compound functions as an end group of the polyester molecular chain or an end group of the branched chain, thereby suppressing excessive crosslinking of the polyester (A) and preventing gelation.

Furthermore, in one embodiment of the present invention, the polyester (A) contains a polyfunctional compound having at least three functional groups selected from a carboxyl group, a hydroxy group and an ester-forming group thereof as a copolymerization component. Also good. Examples of the polyfunctional compound include trimesic acid, trimellitic acid, 1,2,3-benzenetricarboxylic acid, pyromellitic acid, 3,4,3 ′, 4′-biphenyltetracarboxylic acid, and 1,4,5. , 8-Naphthalenetetracarboxylic acid and other aromatic polycarboxylic acids; 1,3,5-cyclohexanetricarboxylic acid and other alicyclic polycarboxylic acids; ethanetricarboxylic acid, propanetricarboxylic acid and butanetetracarboxylic acid and other aliphatic polycarboxylic acids Carboxylic acid; aromatic polyhydric alcohol such as 1,3,5-trihydroxybenzene; such as trimethylolmethane, trimethylolethane, trimethylolpropane, pentaerythritol, glycerin, hexanetriol and 1,3,5-cyclohexanetriol Aliphatic or cycloaliphatic polyhydric alcohols; 4-hydro Siisophthalic acid, 3-hydroxyisophthalic acid, 2,3-dihydroxybenzoic acid, 2,4-dihydroxybenzoic acid, 2,5-dihydroxybenzoic acid, 2,6-dihydroxybenzoic acid, protocatechuic acid, gallic acid and 2,4 -Aromatic hydroxycarboxylic acids such as dihydroxyphenylacetic acid; Aliphatic hydroxycarboxylic acids such as tartaric acid and malic acid; and esters thereof.
The proportion of the structural unit derived from the polyfunctional compound is preferably 10 mol% or less, more preferably 5 mol% or less, still more preferably 3 mol% or less, based on the total number of moles of all the structural units of the polyester (A). It is.
Among those described above, preferable polyfunctional compounds include trimellitic acid, pyromellitic acid, trimesic acid, trimethylolpropane, and pentaerythritol from the viewpoint of ease of production of polyester (A) and production cost.

In one embodiment of the present invention, the polyester (A) may contain at least one structural unit derived from a metal sulfonate.
The structural unit derived from the metal sulfonate can be introduced into the polyester (A) by using the metal sulfonate group-containing compound as a copolymer component of the polyester.
The metal sulfonate group-containing compound is represented by the formula: X—R, X is a dicarboxylic acid or diol, and R is —SO ₃ M. M is represented by a metal in the +1 or +2 state that can be selected from Li, Na, Zn, Sn, K and Ca. Among these, Na or Li is preferable in terms of easy production. The metal sulfonate group-containing compound contains two or more functional groups, and R is directly bonded to a side chain such as a diol, an aromatic ring of X which is a dicarboxylic acid, or a methylene group.
Examples of X in the formula include aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, orthophthalic acid, naphthalenedicarboxylic acid, diphenyl ether dicarboxylic acid, diphenyl-4,4-dicarboxylic acid; oxalic acid, malonic acid, succinic acid, A compound obtained by removing one hydrogen atom from a compound selected from linear aliphatic dicarboxylic acids such as glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid and sebacic acid; and cycloaliphatic dicarboxylic acids such as cyclohexanedicarboxylic acid Is mentioned. Among these, isophthalic acid is preferable because it is easy to produce.
X in the formula includes ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,9-nonanediol, diethylene glycol, and the like. Linear aliphatic glycols: those obtained by removing one hydrogen atom from cyclohexanediol such as 1,3-cyclohexanediol and alicyclic diols such as cyclohexanedimethanol. Of these, ethylene glycol, diethylene glycol and cyclohexanediol are preferred.
Among these, in the present invention, it is particularly preferable to have a metal sulfoisophthalic acid unit introduced by a metal sulfonate group-containing compound in which X in the formula is isophthalic acid. By having a metal sulfoisophthalic acid unit, the compatibility between the polyester (A) and the polyamide (B) can be increased, and the transparency can be improved.
The amount ratio of the metal sulfonate (—SO ₃ M) is preferably 0.1 mol% or more, more preferably 0.2 mol% or more, still more preferably with respect to the total number of moles of all the structural units of the polyester (A). Is 0.4 mol% or more, preferably 10 mol% or less, more preferably 5 mol% or less, still more preferably 4 mol% or less, and particularly preferably 2 mol% or less. The amount ratio of the metal sulfonate can be measured by measuring the amount of sulfur and metal in the polyester (A) and converting it to a molar amount.

The production method of the polyester (A) can be produced by applying a direct esterification method or a transesterification method, which are known methods.
Examples of the polycondensation catalyst to be used include known antimony compounds such as antimony trioxide and antimony pentoxide, germanium compounds such as germanium oxide, titanium compounds such as titanium acetate, and aluminum compounds such as aluminum chloride. However, it is not limited to these.
Further, as another production method, the polyester (A) may be produced by adopting a method of transesterifying different kinds of polyesters by a method such as a long residence time and / or high temperature extrusion.

  The polyester (A) is a dimer of an ethylene glycol component and may contain a small amount of diethylene glycol by-product units that are formed in a small amount in the polyester production process. In order for the multilayer structure of the present invention to maintain good physical properties, the proportion of diethylene glycol units in the polyester (A) is preferably as low as possible. The proportion of the structural unit derived from diethylene glycol is preferably 3 mol% or less, more preferably 1 to 2 mol%, based on all the structural units of the polyester (A).

  The moisture content of the polyester (A) is preferably 200 ppm or less, and more preferably 100 ppm or less. The polyester (A) may be one whose moisture content is reduced by drying or the like before being formed into a multilayer structure.

  The intrinsic viscosity of the polyester (A) (phenol / 1,1,2,2, -tetrachloroethane = a value measured at 25 ° C. in a mixed solvent of 60/40 mass ratio) is not particularly limited, but is usually 0.5 to It is desirable to be 2.0 dl / g, preferably 0.6 to 1.5 dl / g. When the intrinsic viscosity is 0.5 dl / g or more, the multilayer structure can exhibit mechanical properties necessary as a structure.

  In addition, the polyester (A) used for this invention may also contain the material (for example, a polyester monomer, a catalyst, and an oligomer) derived from regenerated polyester, used polyester, or industrial recycled polyester.

  Polyester (A) may be used alone or in combination of two or more.

  In this invention, polyester (A) is contained in the range of 94-99.9 mass% in the resin composition (C) which comprises an inner layer and an outer layer. The amount ratio of the polyester (A) in the resin composition (C) is preferably 94.5% by mass or more, more preferably 95.0% by mass or more, and preferably 99.5% by mass or less. Preferably it is 98.5 mass% or less, More preferably, it is 97.5 mass% or less.

[Polyamide (B)]
The polyamide (B) is a polyamide containing a diamine unit containing 70 mol% or more of a metaxylylenediamine unit and a dicarboxylic acid unit, and is composed of the diamine unit and the dicarboxylic acid unit in the repeating structural unit of the polymer main chain. Amide bond {—NH—C (═O) —}.

  The diamine unit in the polyamide (B) contains a metaxylylenediamine unit in an amount of 70 mol% or more, preferably 80 mol% or more, more preferably 90 mol% or more, and further preferably 95 mol% or more. By including the metaxylylenediamine unit in the above range, not only water resistance but also high strength and high elastic modulus and excellent gas barrier properties can be expressed, and molding of a resin composition containing polyamide (B) The property can be improved.

  Examples of the diamine constituting the diamine unit other than the metaxylylenediamine unit include aromatic diamines such as orthoxylylenediamine, paraxylylenediamine, and paraphenylenediamine; 1,2-bis (aminomethyl) cyclohexane, 1,3- Cycloaliphatic diamines such as bis (aminomethyl) cyclohexane and 1,4-bis (aminomethyl) cyclohexane; ethylenediamine, 1,3-propylenediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, heptamethylenediamine , Octamethylenediamine, nonamethylenediamine, decamethylenediamine, undecamethylene, dodecamethylenediamine, 2-methyl-1,5-pentanediamine, 1-amino-3-aminomethyl-3,5,5-trimethylcycle Aliphatic diamines such as hexane; can be exemplified a polyether diamine having an ether bond represented by Huntsman Corp. JEFFAMINE and Erasutamin (all trade names), but are not limited to. These can be used alone or in combination of two or more. Of these, paraxylylenediamine is preferable.

［式（II−１）中、ｎは２〜１８の整数であり、式（II−２）中、Ａｒはアリーレン基である。］ The dicarboxylic acid unit constituting the polyamide (B) is not particularly limited, and an aliphatic dicarboxylic acid unit, an alicyclic dicarboxylic acid unit, and an aromatic dicarboxylic acid unit are used. Among these, since it is excellent in heat resistance and molding processability, a linear aliphatic dicarboxylic acid unit represented by the following general formula (II-1) and an aromatic dicarboxylic acid unit represented by the following general formula (II-2) It is preferable to contain at least one dicarboxylic acid unit selected from Either the linear aliphatic dicarboxylic acid unit represented by the general formula (II-1) or the aromatic dicarboxylic acid unit represented by the following general formula (II-2) may be used alone, or a combination thereof may be used. It may be used.

[In Formula (II-1), n is an integer of 2-18, and Ar is an arylene group in Formula (II-2). ]

  Each amount ratio of the linear aliphatic dicarboxylic acid unit represented by the general formula (II-1) and the aromatic dicarboxylic acid unit represented by the general formula (II-2) contained in the dicarboxylic acid unit constituting the polyamide (B) Is not particularly limited, but from the viewpoint of the reactivity during polymerization, and the crystallinity and moldability of the polyamide compound, the total amount in the dicarboxylic acid unit is preferably 50 mol% or more, more preferably 70 mol% or more, still more preferably Is 80 mol% or more, particularly preferably 90 mol% or more. When a linear aliphatic dicarboxylic acid unit and an aromatic dicarboxylic acid unit are used in combination, the total amount of these units only needs to satisfy the above range.

  Examples of dicarboxylic acid units other than the dicarboxylic acid unit represented by formula (II-1) or (II-2) include oxalic acid, malonic acid, fumaric acid, maleic acid, 1,3-benzenediacetic acid, 1,4 -Although the dicarboxylic acid unit obtained from dicarboxylic acid, such as benzenediacetic acid, can be illustrated, it is not restrict | limited to these.

  In the dicarboxylic acid unit in the polyamide (B), the content ratio of the linear aliphatic dicarboxylic acid unit to the aromatic dicarboxylic acid unit (linear aliphatic dicarboxylic acid unit / aromatic dicarboxylic acid unit) is particularly limited. It is determined appropriately according to the application. For example, when the purpose is to increase the glass transition temperature of the polyamide (B) to lower the crystallinity of the polyamide (B), the linear aliphatic dicarboxylic acid unit / aromatic dicarboxylic acid unit is the sum of both units. Is preferably 0/100 to 60/40, more preferably 0/100 to 40/60, and still more preferably 0/100 to 30/70. When the purpose is to lower the glass transition temperature of the polyamide (B) to give the polyamide (B) flexibility, the linear aliphatic dicarboxylic acid unit / aromatic dicarboxylic acid unit is the sum of both units. When 100, it is preferably 40/60 to 100/0, more preferably 60/40 to 100/0, and still more preferably 70/30 to 100/0.

When the purpose is to impart moderate flexibility in addition to imparting an appropriate glass transition temperature and crystallinity to the polyamide (B), a linear aliphatic dicarboxylic acid represented by the general formula (II-1) It preferably contains an acid unit.
In general formula (II-1), n represents the integer of 2-18, Preferably it is 3-16, More preferably, it is 4-12, More preferably, it is 4-8.
Examples of the compound constituting the linear aliphatic dicarboxylic acid unit represented by the general formula (II-1) include succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, 1,10-decane. Examples thereof include, but are not limited to, dicarboxylic acid, 1,11-undecanedicarboxylic acid, 1,12-dodecanedicarboxylic acid and the like. These can be used alone or in combination of two or more.

What is necessary is just to determine suitably the kind of linear aliphatic dicarboxylic acid unit shown by general formula (II-1) used for this invention, and its quantity ratio according to the use of the multilayered structure of this invention.
In addition to imparting excellent gas barrier properties to polyamide (B), from the viewpoint of maintaining heat resistance after heat sterilization, it is selected from the group consisting of adipic acid units, sebacic acid units and 1,12-dodecanedicarboxylic acid units It is preferable that at least one selected from the total is contained in the dicarboxylic acid unit in an amount of 50 mol% or more, more preferably 70 mol% or more, still more preferably 80 mol% or more, and particularly preferably 90 mol% or more.

  Further, in addition to imparting excellent gas barrier properties to the polyamide (B), from the viewpoint of imparting appropriate thermal properties such as glass transition temperature and melting point, the adipic acid unit is incorporated into the linear aliphatic dicarboxylic acid unit. It is preferable to contain 50 mol% or more. Moreover, it is preferable that 50 mol% or more of sebacic acid units are contained in the linear aliphatic dicarboxylic acid unit from the viewpoint of imparting appropriate gas barrier properties and molding processability to the polyamide (B). Further, from the viewpoint of imparting low water absorption, weather resistance, and heat resistance, it is preferable that 50 mol% or more of 1,12-dodecanedicarboxylic acid units are contained in the linear aliphatic dicarboxylic acid units.

In addition to imparting further gas barrier properties to the polyamide (B), the aromatic dicarboxylic acid represented by the general formula (II-2) is used for the purpose of facilitating the moldability of the multilayer structure. Preferably it contains units.
In general formula (II-2), Ar represents an arylene group. The arylene group is preferably an arylene group having 6 to 30 carbon atoms, more preferably 6 to 15 carbon atoms, and examples thereof include a phenylene group and a naphthylene group.
Examples of the compound that can constitute the aromatic dicarboxylic acid unit represented by the general formula (II-2) include terephthalic acid, isophthalic acid, and 2,6-naphthalenedicarboxylic acid, but are not limited thereto. . These can be used alone or in combination of two or more.

What is necessary is just to determine suitably the kind of aromatic dicarboxylic acid unit shown by general formula (II-2) used for this invention, and its quantity ratio according to the use of the multilayer structure of this invention.
The aromatic dicarboxylic acid unit in the polyamide (B) is a total of at least one selected from the group consisting of an isophthalic acid unit, a terephthalic acid unit, and a 2,6-naphthalenedicarboxylic acid unit in the aromatic dicarboxylic acid unit. The content is preferably 50 mol% or more, more preferably 70 mol% or more, still more preferably 80 mol% or more, and particularly preferably 90 mol% or more. Among these, it is preferable to contain isophthalic acid and / or terephthalic acid in the aromatic dicarboxylic acid unit. The content ratio of the isophthalic acid unit to the terephthalic acid unit (isophthalic acid unit / terephthalic acid unit) is not particularly limited and is appropriately determined depending on the application. For example, from the viewpoint of reducing the appropriate glass transition temperature and crystallinity, the total of both units is preferably 100/100 to 100/0, more preferably 0/100 to 60/40, and even more preferably 0. / 100 to 40/60, more preferably 0/100 to 30/70.

The polyamide (B) used in the present invention is not particularly limited as long as it is a polyamide including a diamine unit and a dicarboxylic acid unit containing 70 mol% or more of metaxylylenediamine units. Since the mechanical properties are excellent, a polyamide containing a diamine unit containing 70 mol% or more of metaxylylenediamine units and a dicarboxylic acid unit containing 70 mol% or more of adipic acid units is used as the polyamide (B). It is preferable.
In another embodiment of the present invention, since the moldability is good in addition to the barrier property and the mechanical properties, the polyamide (B) is a diamine containing 70 mol% or more of metaxylylenediamine units. It is preferable to use a polyamide containing a unit and a dicarboxylic acid unit containing 70 to 99 mol% of adipic acid units and 1 to 30 mol% of isophthalic acid units.

The number average molecular weight (Mn) of the polyamide (B) is not particularly limited, but is preferably 5,000 or more, more preferably 10,000 or more, and further preferably 15,000 or more. Moreover, 50,000 or less is preferable, More preferably, it is 45,000 or less, More preferably, it is 40,000 or less. When the number average molecular weight of the polyamide (B) is in the above range, there are few unreacted materials as the polyamide, and the properties are stable. The number average molecular weight of the polyamide (B) can be determined from the quantitative value of the terminal amino group concentration and the terminal carboxyl group concentration by the following formula.
Number average molecular weight = 2 × 1,000,000 / ([NH ₂ ] + [COOH])
[NH ₂ ]: Terminal amino group concentration (μeq / g)
[COOH]: Terminal carboxyl group concentration (μeq / g)

  The polyamide (B) can be produced by polymerizing a diamine component constituting a diamine unit and a dicarboxylic acid component constituting a dicarboxylic acid unit. The degree of polymerization can be controlled by adjusting the polycondensation conditions and the like. A small amount of monoamine or monocarboxylic acid may be added as a molecular weight modifier during polycondensation. Further, in order to suppress the polycondensation reaction and obtain a desired degree of polymerization, the ratio (molar ratio) between the diamine component and the carboxylic acid component constituting the polyamide may be adjusted by shifting from 1.

  Examples of the polycondensation method of the polyamide (B) include, but are not limited to, a reactive extrusion method, a pressurized salt method, an atmospheric pressure dropping method, and a pressure dropping method. Among these, the atmospheric pressure dropping method and the pressure dropping method are preferable in terms of cost merit because no solvent is used, and the atmospheric pressure dropping method is particularly preferably used. When the reaction temperature is as low as possible, yellowing and gelation of the polyamide resin can be suppressed, and a polyamide resin having a stable property can be obtained.

The normal pressure dropping method is a method in which a dicarboxylic acid component is heated and melted under normal pressure, a diamine component is continuously dropped, and polycondensation is performed while removing condensed water. In this method, the polycondensation reaction is performed while raising the temperature of the reaction system so that the reaction temperature does not fall below the melting point of the polyamide compound to be produced. Compared with the pressurized salt method, the atmospheric pressure dropping method does not use water to dissolve the salt, so the yield per batch is large, and since there is no need to vaporize or condense the raw material components, the reaction rate is low. There is little decrease and the process time can be shortened.
In the pressure dropping method, first, a dicarboxylic acid component is charged into a polycondensation can and heated and melted, and then the diamine component is continuously dropped while pressurizing the inside of the can to preferably about 0.3 to 0.4 MPaG to condense. This is a method of polycondensation while removing water. In this method, the polycondensation reaction is performed while raising the temperature of the reaction system so that the reaction temperature does not fall below the melting point of the polyamide compound to be produced. When the set molar ratio is reached, the addition of the diamine component is terminated, and while gradually raising the inside of the can to normal pressure, the temperature is raised to about the melting point of polyamide (B) + 10 ° C. and maintained, and then gradually increased to 0.02 MPaG. While maintaining the pressure at a low pressure, the polycondensation is continued. When a constant stirring torque is reached, the inside of the can is pressurized to about 0.3 MPaG with nitrogen to recover the polyamide (B).
The method for adjusting the melt viscosity of the polyamide (B), that is, the number average molecular weight, is not limited to the method for determining the polymerization end point with the stirring torque in the polymerization method described above, but the molar ratio is set to 1 in the monomer charging stage in advance. There is a method of setting the target number average molecular weight by adjusting by shifting from the above.

In the polycondensation of polyamide, it is preferable to add a phosphorus atom-containing compound from the viewpoint of promoting the amidation reaction.
Examples of the phosphorus atom-containing compound include phosphinic acid compounds such as dimethylphosphinic acid and phenylmethylphosphinic acid; hypophosphorous acid, sodium hypophosphite, potassium hypophosphite, lithium hypophosphite, magnesium hypophosphite, Diphosphite compounds such as calcium hypophosphite and ethyl hypophosphite; phosphonic acid, sodium phosphonate, potassium phosphonate, lithium phosphonate, potassium phosphonate, magnesium phosphonate, calcium phosphonate, phenylphosphonic acid, ethylphosphone Phosphonic acid compounds such as acid, sodium phenylphosphonate, potassium phenylphosphonate, lithium phenylphosphonate, diethyl phenylphosphonate, sodium ethylphosphonate, potassium ethylphosphonate; phosphonous acid, sodium phosphonite, phosphorous acid Lithium phosphonate, potassium phosphonite, magnesium phosphonite, calcium phosphonite, phenyl phosphonite, sodium phenyl phosphonite, potassium phenyl phosphonite, lithium phenyl phosphonite, ethyl phenyl phosphonite, etc. Phosphonic acid compounds; phosphorous acid, sodium hydrogen phosphite, sodium phosphite, lithium phosphite, potassium phosphite, magnesium phosphite, calcium phosphite, triethyl phosphite, triphenyl phosphite, pyro-subite Examples thereof include phosphorous acid compounds such as phosphoric acid.
Among these, hypophosphite metal salts such as sodium hypophosphite, potassium hypophosphite, lithium hypophosphite and the like are particularly preferable because they are highly effective in promoting amidation reaction and excellent in anti-coloring effect. In particular, sodium hypophosphite is preferred. In addition, the phosphorus atom containing compound which can be used by this invention is not limited to these compounds.
The addition amount of the phosphorus atom-containing compound is preferably 0.1 to 1000 ppm, more preferably 1 to 600 ppm, and still more preferably 5 to 400 ppm in terms of phosphorus atom concentration in the polyamide. If it is 0.1 ppm or more, the polyamide is difficult to be colored during the polymerization and the transparency becomes high. If it is 1000 ppm or less, the polyamide is difficult to gel, and the mixing of fish eyes considered to be caused by the phosphorus atom-containing compound can be reduced, and the appearance of the molded product becomes good.

Further, it is preferable to add an alkali metal compound in combination with the phosphorus atom-containing compound in the polyamide polycondensation system. In order to prevent coloring of the polyamide during polycondensation, a sufficient amount of phosphorus atom-containing compound needs to be present, but in some cases, the gelation of the polyamide may be caused, so the amidation reaction rate is adjusted. Therefore, it is preferable to coexist an alkali metal compound.
As the alkali metal compound, alkali metal hydroxide, alkali metal acetate, alkali metal carbonate, alkali metal alkoxide, and the like are preferable. Specific examples of the alkali metal compound that can be used in the present invention include lithium hydroxide, sodium hydroxide, potassium hydroxide, rubidium hydroxide, cesium hydroxide, lithium acetate, sodium acetate, potassium acetate, rubidium acetate, cesium acetate. Sodium methoxide, sodium ethoxide, sodium propoxide, sodium butoxide, potassium methoxide, lithium methoxide, sodium carbonate and the like, but can be used without being limited to these compounds. The ratio of the phosphorus atom-containing compound to the alkali metal compound is such that the phosphorus atom-containing compound / alkali metal compound = 1.0 / 0.05 to 1.0 / from the viewpoint of controlling the polymerization rate and reducing the yellowness. The range of 1.5 is preferable, more preferably 1.0 / 0.1 to 1.0 / 1.2, and still more preferably 1.0 / 0.2 to 1.0 / 1.1.

  In this invention, 0.1-6 mass% of polyamide (B) is contained in the resin composition (C) which comprises an inner layer and an outer layer. The blending amount of the polyamide (B) in the resin composition is preferably 0.5% by mass or more, more preferably 1.5% by mass or more, still more preferably 2.5% by mass or more, and preferably 5%. 0.5% by mass or less, more preferably 5.0% by mass or less.

  In this invention, you may mix | blend various additives with the resin composition (C) which comprises an inner layer and an outer layer in the range which does not impair the characteristic of this invention. For example, one or a plurality of other resins such as polyester other than polyester (A), polyamide other than polyamide (B), polyolefin, and phenoxy resin can be blended. In addition, inorganic fillers such as glass fibers and carbon fibers; plate-like inorganic fillers such as glass flakes, talc, kaolin, mica, montmorillonite, and organized clay; impact modifiers such as various elastomers; crystal nucleating agents Lubricants such as fatty acid amides and fatty acid amides; antioxidants such as organic or inorganic halogen compounds, hindered phenols, hindered amines, hydrazines, sulfur compounds, phosphorus compounds; anti-coloring agents, benzotriazoles UV absorbers, mold release agents, plasticizers, colorants, UV absorbers, infrared absorbers (reheat additive), flame retardants, etc. to accelerate the heating of the preform and shorten the cycle time during molding The additive of can be illustrated. One or more additives can be used as necessary. The compounding amount of the additive in the resin composition (C) constituting the inner layer and the outer layer is not particularly limited as long as it does not impair the characteristics of the present invention.

  In the present invention, the resin composition constituting the inner layer and the resin composition constituting the outer layer may have exactly the same composition, and the type and amount ratio of the polyester (A) and the polyamide (B), You may have a composition which changes with kinds, quantity ratio, etc. of various additives. However, it is preferable that the resin composition constituting the inner layer and the resin composition constituting the outer layer have the same composition in terms of easy production and obtaining excellent delamination strength.

2. Barrier layer In the multilayer structure of the present invention, the barrier layer is a layer that is located between the inner layer and the outer layer and prevents oxygen from entering the inside of the container through the vessel wall from the outside of the container. The barrier layer used in the multilayer structure of the present invention may be a single layer or two or more layers.

  In the present invention, the barrier layer comprises 1 to 40% by mass of a polyester (A) containing a dicarboxylic acid unit containing 80 mol% or more of a terephthalic acid unit and a diol unit containing 80 mol% or more of an ethylene glycol unit, and metaxylylene diene. It is comprised from the resin composition (D) containing 60-99 mass% of polyamides (B) containing the diamine unit which contains 70 mol% or more of amine units, and the dicarboxylic acid unit. The polyester (A) and the polyamide (B) are as described in the polyester (A) and the polyamide (B) used for the resin composition (C) constituting the inner layer and the outer layer, respectively.

  The polyester (A) used in the resin composition (D) constituting the barrier layer should contain a dicarboxylic acid unit containing 80 mol% or more of terephthalic acid units and a diol unit containing 80 mol% or more of ethylene glycol units. There is no particular limitation. It may have the same composition as the polyester (A) used in the resin composition (C) constituting the inner layer and the outer layer, or may have a different composition. However, the polyester (A) used for the resin composition (D) constituting the barrier layer constitutes the inner layer and the outer layer in that the delamination can be more effectively prevented and the production is easy. It is preferable to have the same composition as the polyester (A) used for the resin composition (C).

  The polyamide (B) used in the resin composition (D) constituting the barrier layer is not particularly limited as long as it contains a diamine unit and a dicarboxylic acid unit containing 70 mol% or more of metaxylylenediamine units. It may have the same composition as the polyamide (B) used in the resin composition (C) constituting the inner layer and the outer layer, or may have a different composition. However, the polyamide (B) used for the barrier layer is used for the resin composition (C) constituting the inner layer and the outer layer in that the delamination can be more effectively prevented and the production is easy. It preferably has the same composition as the polyamide (B).

In this invention, the compounding quantity of polyester (A) contained in the resin composition (D) which comprises a barrier layer is 1-40 mass, Preferably it is 2 mass% or more, More preferably, it is 3 mass% or more, More preferably, it is 5 mass% or more, Most preferably, it is 15 mass% or more, Preferably it is 35 mass% or less, More preferably, it is 25 mass% or less.
Moreover, the compounding quantity of the polyamide (B) contained in the resin composition (D) which comprises a barrier layer is 60-99 mass%, Preferably it is 65 mass% or more, More preferably, it is 75 mass% or more. Moreover, it is preferably 98% by mass or less, more preferably 97% by mass or less, and still more preferably 95% by mass or less.
By including the polyester (A) and the polyamide (B) in the above range in the resin composition (D) constituting the barrier layer, delamination against dropping or impact from the outside is maintained while maintaining high barrier properties. A multilayer structure that is unlikely to occur and excellent in impact resistance can be obtained.

  In this invention, you may mix | blend various additives with the resin composition (D) which comprises a barrier layer in the range which does not impair the characteristic of this invention. As an additive which can be mix | blended with a barrier layer, the thing similar to the additive used for the resin composition (C) which comprises an inner layer and an outer layer can be used. One or more additives can be used as necessary.

  When the multilayer structure of the present invention has two or more barrier layers, the resin composition (D) constituting the barrier layer may have the same composition or a different composition. .

  The multilayer structure of the present invention has at least a part of the multilayer structure including the inner layer, the outer layer, and at least one barrier layer located between the inner layer and the outer layer. In the multilayer structure, the inner layer and the outer layer are included. And each layer of the barrier layer is composed of a resin composition containing polyester (A) and polyamide (B) in a predetermined quantitative ratio, thereby improving interlayer adhesion while maintaining high barrier properties, and from falling or externally It has a structure in which delamination hardly occurs with respect to the impact.

  The multilayer structure of the multilayer structure of the present invention is not particularly limited as long as it has an inner layer, an outer layer, and at least one barrier layer positioned between the inner layer and the outer layer, but the object of the present invention is impaired. Other layers including an adhesive layer, a protective layer, a barrier coating layer, a printing layer, and the like may be included as long as they are not included.

  In one embodiment of the present invention, the multilayer structure of the multilayer structure of the present invention preferably has, for example, a three-layer structure of inner layer 1 / barrier layer 2 / outer layer 3 as shown in FIG.

When the multilayer structure of the present invention has two or more barrier layers, an intermediate layer may be provided between the barrier layers. For example, in one embodiment of the present invention, the multilayer structure of the multilayer structure of the present invention has a five-layer structure of inner layer 1 / barrier layer 2A / intermediate layer 4 / barrier layer 2B / outer layer 3 as shown in FIG. It is preferable to have. The composition of the resin composition (D) constituting the plurality of barrier layers may be the same or different.
As the intermediate layer, since the interlayer adhesion with each barrier layer is good and the strength of the structure can be maintained, and further excellent in molding processability, a dicarboxylic acid unit containing 80 mol% or more of terephthalic acid units and Polyester (A) containing 94 to 99.9% by mass of a diol unit containing 80 mol% or more of ethylene glycol units, and a polyamide containing a diamine unit and dicarboxylic acid units containing 70 mol% or more of metaxylylenediamine units ( B) A layer made of the resin composition (E) containing 0.1 to 6% by mass is preferably used.
The polyester (A) and polyamide (B) contained in the resin composition (E) and the amount ratio thereof are the same as those of the resin composition (C) constituting the inner layer and the outer layer, and a preferred embodiment and a preferred range of the amount ratio. The same applies to the above. As the resin composition (E) constituting the intermediate layer, one having the same composition as the resin composition (C) constituting the inner layer and the outer layer can be used, and the inner layer and the outer layer are constituted within the above range. You may use what has a composition different from a resin composition (C). By having an intermediate layer made of the resin composition (E) between the barrier layer and the barrier layer, a plurality of barrier layers can be laminated while improving the interlayer adhesion of the barrier layer / intermediate layer / barrier layer. And the barrier property of the multilayer structure can be further improved.
In addition, as long as the objective of this invention is not impaired, you may have layers other than the above as an intermediate | middle layer, for example, an adhesive bond layer, an oxygen absorption layer, etc.

  In the multilayer structure of the present invention, the thicknesses of the inner layer, the outer layer, the barrier layer, and the intermediate layer may be appropriately selected according to the use and purpose of the multilayer structure.

  The ratio of the barrier layer in the multilayer structure of the present invention is not particularly limited, but is preferably 1% by mass or more, more preferably 2% by mass or more, and still more preferably based on the total mass of the multilayer structure. When the content is 3% by mass or more, preferably 20% by mass or less, more preferably 15% by mass or less, and still more preferably 10% by mass or less, a multilayer structure having good barrier properties can be obtained.

  The multilayer structure of the present invention can be suitably used as various containers or preforms thereof. In particular, it is suitable as a container for packaging a substance that hates oxygen, such as beverages, foods, cosmetics and pharmaceuticals, or a preform thereof.

The shape of the multilayer structure of the present invention is not particularly limited, and can be any shape such as a bottle, a deep-drawn container, a cup-shaped container, or a preform (preform) thereof, depending on the application and purpose. . The shape of the bottle is preferably a general shape of a plastic bottle.
When the multilayer structure of the present invention is various containers, the thickness of the inner layer is preferably 0.01 mm or more, more preferably 0.03 mm or more, still more preferably 0.05 mm or more, and preferably 2.0 mm. Hereinafter, it is more preferably 1.5 mm or less, and still more preferably 1.0 mm or less.
The thickness of the outer layer is preferably 0.01 mm or more, more preferably 0.05 mm or more, still more preferably 0.05 mm or more, and preferably 2.0 mm or less, more preferably 1.5 mm or less, still more preferably. Is 1.0 mm or less.
Further, the thickness of the barrier layer is preferably 0.005 mm or more, more preferably 0.01 mm or more, still more preferably 0.02 mm or more, and preferably 0.2 mm or less, more preferably 0.15 mm or less, Preferably it is 0.1 mm or less. When it has two or more barrier layers, it is preferable that the total thickness of each barrier layer has the above thickness.
Moreover, when it has two or more barrier layers and has an intermediate layer between the barrier layers, the thickness of the intermediate layer is preferably 0.01 mm or more, more preferably 0.03 mm or more. Further, it is 0.05 mm or more, preferably 2.0 mm or less, more preferably 1.5 mm or less, and still more preferably 1.0 mm or less.

  The capacity of the multilayer structure of the present invention is preferably 0.1 to 2.0 L, preferably 0.2 to 1.5 L, and preferably 0.3 to 1.0 L from the viewpoint of storage stability of the contents. More preferably it is.

The thickness of the multilayer structure in the case where the multilayer structure of the present invention is various containers is not particularly limited and may be appropriately selected depending on the application and purpose, but is usually in the range of 0.2 to 4.0 mm. preferable.
When the multilayer structure of the present invention is a preform, the container after blow-drawing may be appropriately selected so as to have the above thickness.

  In the multilayer structure of the present invention, for example, using an injection molding machine having two injection cylinders, the resin composition (C) constituting the inner layer and the outer layer is formed from the skin side injection cylinder, and the barrier layer is formed. The resin composition (D) to be obtained can be obtained as a multilayer preform by injecting the resin composition (D) from the core side injection cylinder into the mold cavity through the mold hot runner. Moreover, the obtained multilayer preform can be obtained as a molded body having an arbitrary shape by further biaxially stretching blow molding by a known method. By this method, a multilayer structure having an arbitrary bottle shape can be obtained.

  As the biaxial stretch blow molding method of the multilayer preform, a generally known method such as a so-called cold parison method or hot parison method can be used. For example, the surface of the multi-layer preform is stretched in the axial direction by mechanical means such as heating to 80 to 120 ° C. and then pressed with a core rod insert, and then normally 2 to 4 MPa of high-pressure air is blown and stretched in the transverse direction. A blow molding method may be mentioned. Alternatively, there is a method in which the mouth of the multilayer preform is crystallized, the surface is heated to 80 to 120 ° C., and then blow-molded in a mold at 90 to 150 ° C.

  The heating temperature of the multilayer preform is usually 80 to 120 ° C, preferably 90 to 110 ° C. When the heating temperature is lower than 80 ° C., the heating becomes insufficient, and the inner layer, the outer layer or the barrier layer, and further the intermediate layer may be cold-drawn and whitened. A temperature higher than 120 ° C. is not preferable because the barrier layer is crystallized and whitened. In addition, the delamination resistance may decrease.

For example, a multilayer structure which is a blow molded article having a three-layer structure can be obtained by biaxially stretching blow-molding a multilayer preform having a three-layer structure by a known method.
The manufacturing method of the multilayer preform having a three-layer structure is not particularly limited, and a known method can be used. For example, in the step of injecting the resin composition (C) constituting the inner layer and the outer layer from the skin side injection cylinder and injecting the resin composition (D) constituting the barrier layer from the core side injection cylinder, first, the inner layer and the outer layer are injected. The resin composition (C) constituting the barrier layer, the resin composition (D) constituting the barrier layer and the resin composition (C) constituting the inner layer and the outer layer, and then injecting the inner layer and the outer layer. A multilayer preform having a three-layer structure (inner layer / barrier layer / outer layer) can be produced by injecting a necessary amount of the resin composition (C) to fill the mold cavity.
For example, a multilayer structure which is a blow molded article having a five-layer structure can be obtained by biaxially stretching blow-molding a multilayer preform having a five-layer structure by a known method.
For example, when the resin composition constituting the inner layer and the outer layer and the resin composition constituting the intermediate layer have the same composition, first, the resin composition (C) that constitutes the inner layer, the intermediate layer, and the outer layer (C) ( Alternatively, the resin composition (E)) is injected, the resin composition (D) constituting the barrier layer is then injected alone, and finally the resin composition (C) constituting the inner layer, the intermediate layer and the outer layer is required. A multilayer preform having a five-layer structure (inner layer / barrier layer / intermediate layer / barrier layer / outer layer) can be produced by injection and filling the mold cavity.
When the resin composition (C) constituting the inner layer and the outer layer and the resin composition (E) constituting the intermediate layer have different compositions, first, the resin composition (C) constituting the inner layer and the outer layer is selected. Injection from the injection cylinder, then the resin composition (D) constituting the barrier layer is separately injected from another injection cylinder, and finally the resin composition (E) constituting the intermediate layer is injected in the required amount to form a cavity. By satisfying −, a multilayer preform having a five-layer structure (inner layer / barrier layer / intermediate layer / barrier layer / outer layer) can be produced.
The method for producing the multilayer preform is not limited to the above method. A person skilled in the art can manufacture a multilayer preform having a desired multilayer structure with reference to the above method.

In another preferred embodiment of the present invention, the multilayer structure of the present invention is formed by forming a multilayer sheet by a conventionally known method (such as an extrusion laminating method, a coextrusion method, or a fusion method using heat). It is good also as a desired shape by shape | molding. By this method, a multilayer structure having an arbitrary deep drawing shape or cup shape is obtained.
The method for producing the multilayer sheet is not particularly limited, but the coextrusion method is preferable in terms of production efficiency. In the co-extrusion method, two or more extruders are used, and before the barrier layer is extruded from the die lip, the inner layer and the outer layer are laminated on both surfaces in the multi-manifold die and extruded simultaneously from the die lip. It is a method of obtaining the multilayer sheet | seat which is a precursor of this.
Examples of a method for thermoforming the obtained precursor multilayer sheet to form a multilayer structure include, but are not limited to, general vacuum forming or pressure forming.

The multilayer structure of the present invention only needs to have at least a part of the multilayer structure including the inner layer, the outer layer, and at least one barrier layer positioned between the inner layer and the outer layer. There may be a portion that does not have.
For example, when the multilayer structure of the present invention has the shape of a preform as shown in FIG. 3 or the shape of a bottle as shown in FIG. (That is, the body portion may have a three-layer structure of inner layer 1 / barrier layer 2 / outer layer 3), and the barrier layer 2 may be close to the tip or bottom of the plug portion. May not extend.
Further, the barrier layer is not necessarily a continuous layer, and may be a discontinuous layer as long as the barrier property is not significantly impaired. In the case where the barrier layer is a discontinuous layer, for example, a region where the barrier layer is present and a region where the barrier layer is not present are arranged in a striped shape or a strip shape in the container body to enhance the peeling prevention effect. Is desirable.
The same applies when the multilayer structure of the present invention is a deep-drawn container, a cup-shaped container or the like.

The multilayer structure of the present invention prevents oxygen from entering from the outside of the container, hardly causes delamination due to dropping or external impact, is easy to handle, hardly causes poor appearance, and stabilizes the contents. Can be saved.
In addition, the multilayer structure of the present invention is less likely to cause delamination due to dropping or impact, and the contents can be stably stored even in a shape including uneven portions and bent portions where delamination is likely to occur. The shape of the structure is not limited to a shape with few concavo-convex portions and bent portions, and has an advantage that the degree of freedom in design is increased.

  The multilayer structure of the present invention is suitable as a container for packaging a substance that hates oxygen, such as beverages, foods, cosmetics, and pharmaceuticals, or a preform thereof. For example, carbonated drinks, juice, water, milk, sake, whiskey, shochu, coffee, tea, jelly drinks, health drinks and other liquid drinks; seasonings, sauces, soy sauce, dressings, liquid soup seasonings, etc .; liquid soups, etc. Suitable for storage and storage of various items such as liquid foods; various solid foods; liquid or solid pharmaceuticals or quasi-drugs; cosmetics such as lotions, cosmetic emulsions, hair styling agents, hair dyes, shampoos, etc. Used for.

  In addition, before and after filling these articles, the multilayer structure and contents can be sterilized in a form suitable for the article to be the contents. Sterilization methods include hot water treatment at 100 ° C. or lower, pressurized hot water treatment at 100 ° C. or higher, heat sterilization such as ultra-high temperature heat treatment at 130 ° C. or higher, electromagnetic wave sterilization of ultraviolet rays, micro breakage, gamma rays, etc., ethylene oxide And gas sterilization such as hydrogen peroxide and hypochlorous acid.

  EXAMPLES Hereinafter, although this invention is demonstrated more concretely using an Example and a comparative example, this invention is not restrict | limited to these Examples at all.

  In each Example and Comparative Example, as will be described later, a preform and a bottle, which are multilayer structures having at least part of a three-layer structure of an inner layer, an outer layer, and a barrier layer, were produced, and the oxygen permeability of the obtained bottles, The delamination resistance and trunk haze were measured and evaluated by the following methods.

(1) Oxygen transmission rate (OTR)
In accordance with ASTM D3985, an oxygen permeability test by MOCON method was performed. MOCON OX-TRAN 2/61 was used for the measurement. The 500 mL bottle obtained in each Example and Comparative Example was filled with 100 mL of water, and the temperature was 23 ° C., the bottle internal humidity was 100% RH, and the external humidity was 50% RH under the condition of an oxygen partial pressure of 0.21 atm. Measurement was performed by circulating 1 atm of nitrogen at 20 mL / min inside the bottle, and detecting oxygen contained in the nitrogen after flowing through the bottle with a coulometric sensor. The lower the value, the less oxygen permeation and the better gas barrier properties.

(2) Delamination Resistance Based on ASTM D2463-95 Procedure B, the delamination height (minimum drop distance at which delamination occurs) was determined by a bottle drop test based on the following method.
First, the bottles obtained in each Example and Comparative Example were filled with 500 mL of colored water, capped, and allowed to stand at 5 ° C. for 24 hours. Thereafter, the bottle was dropped vertically from a predetermined height through a round cylinder so that the bottom part was in contact with the floor. Since the delaminated location becomes cloudy and can be distinguished visually, the presence or absence of delamination of the bottle was visually determined.
Note that delamination occurred in some bottles that had undergone delamination. The drop height interval was increased by 15 cm. The number of test bottles was 30.

(3) Body haze About the bottle obtained by each Example and the comparative example, the body part which has 3 layer structure of an inner layer, a barrier layer, and an outer layer was cut out, and all the layers were piled up in the state which the measurement site | part has not peeled. The measurement was carried out by the transmission method using “SH7000” manufactured by Nippon Denshoku Industries Co., Ltd. (using a 12V / 50W halogen lamp as the light source) in accordance with JIS K7136.

<Example 1>
Using an injection molding machine (manufactured by Sumitomo Heavy Industries, model DU130CI) having two injection cylinders and a two-part mold (manufactured by Kortec), under the conditions shown below, (Y) / (X) / ( A preform having in part a three-layer structure consisting of Y) was produced.
First, as a material constituting the inner layer and outer layer (Y), polyester (A1) (isophthalic acid copolymerized polyethylene terephthalate (polyethylene terephthalate-isophthalate copolymer resin, manufactured by Nihon Unipet, trade name “Unipet BK- 2180 ")) and polyamide (B1) (polymetaxylylene adipamide (manufactured by Mitsubishi Gas Chemical Co., Ltd., MX nylon S6007)) at a ratio shown in Table 1, a resin composition (C) is injected from an injection cylinder. Then, the resin composition (D) blended at a ratio shown in Table 1 as a material constituting the layer (X) to be the barrier layer from another injection cylinder, the resin composition ( C) is injected at the same time, and finally the resin composition (C) constituting the layer (Y) is injected in a necessary amount to fill the cavity. (Y) / (X) / (Y). Preform shape to obtain a parison (27 g) having a portion of three-layer structure of the full-length 95 mm, outer diameter 22 mm, was thick 4.2 mm.
Skin side injection cylinder temperature: 280 ° C
Core side injection cylinder temperature: 280 ° C
Resin channel temperature in mold: 290 ° C
Mold cooling water temperature: 15 ° C
Cycle time: 40s
The material constituting the layer (X) is a resin mixture (D) obtained by blending the polyester (A1) and the polyamide (B1). These materials are melt-kneaded in an injection molding machine. Resin composition (D). Similarly, the material constituting the layer (Y) is made of a resin mixture (C) containing polyester (A1) and polyamide (B1) as raw materials. By melting and kneading these raw materials in an injection molding machine, Resin composition (C).

The obtained preform was biaxially stretched and blow molded by a biaxially stretched blow molding apparatus (manufactured by Frontier, model EFB1000ET) to obtain a petaloid type bottle. The total length of the bottle is 223 mm, the outer diameter is 65 mm, the inner volume is 500 mL, and the bottom is a petaloid shape. Dimples were not provided on the trunk. The biaxial stretch blow molding conditions are as shown below. The ratio of the layer (X) to the total mass of the obtained bottle was 3% by mass.
Preform heating temperature: 108 ° C
Stretching rod pressure: 0.5 MPa
Primary blow pressure: 0.7 MPa
Secondary blow pressure: 2.5 MPa
Primary blow delay time: 0.34 sec
Primary blow time: 0.30 sec
Secondary blow time: 2.0 sec
Blow exhaust time: 0.6 sec
Mold temperature: 30 ℃
The obtained bottles were evaluated for oxygen barrier properties, delamination height, and trunk haze, and are shown in Table 1.

<Examples 2 to 8>
The preform was formed in the same manner as in Example 1 except that the composition shown in Table 1 was used as the resin composition (C) constituting the layer (Y) and the resin composition (D) constituting the layer (X). The bottle was obtained by molding and further subjected to secondary stretch blow. The obtained bottle was evaluated for oxygen barrier properties, delamination height, and trunk haze, and shown in Table 1.

<Comparative Examples 1-7>
The preform was formed in the same manner as in Example 1 except that the composition shown in Table 1 was used as the resin composition (C) constituting the layer (Y) and the resin composition (D) constituting the layer (X). The bottle was obtained by molding and further subjected to secondary stretch blow. The obtained bottles were evaluated for oxygen barrier properties, delamination height, and trunk haze, and are shown in Table 2.

<Examples 9 to 14>
The ratio of the layer (X) to the total mass of the bottle is changed from 3% by mass to 5% by mass, and the resin composition (C) constituting the layer (Y) and the resin composition (D) constituting the layer (X) A bottle was obtained by molding a preform in the same manner as in Example 1 except that the composition shown in Table 3 was used, and then performing secondary stretch blow. The obtained bottles were evaluated for oxygen barrier properties, delamination height, and trunk haze, and are shown in Table 3.

<Comparative Examples 8-11>
The ratio of the layer (X) to the total mass of the bottle is changed from 3% by mass to 5% by mass, and the resin composition (C) constituting the layer (Y) and the resin composition (D) constituting the layer (X) A bottle was obtained by molding a preform in the same manner as in Example 1 except that the composition shown in Table 4 was used, and further subjected to secondary stretch blow. The obtained bottles were evaluated for oxygen barrier properties, delamination height, and trunk haze, and are shown in Table 4.

<Example 15>
Of the resin composition (C) constituting the layer (Y), polyester (A1) is converted to polyester (A2) (polyethylene terephthalate-sodium sulfoisophthalate copolymer resin, intrinsic viscosity = 0.8 dl / g, dicarboxylic acid 100 mol) (Polyethylene terephthalate resin copolymerized with 2.0 mol% of isophthalic acid and 0.45 mol% of sodium 5-sulfoisophthalate with respect to%), and the resin composition (D) constituting layer (X) Among them, a preform was formed in the same manner as in Example 1 except that the composition described in Table 5 was used with the polyester (A1) as the polyester (A2), and a bottle was obtained by performing secondary stretch blow. . The obtained bottle was evaluated for oxygen barrier properties, delamination height, and body haze, and shown in Table 5.

  As shown in Tables 1 to 5, it was found that the bottles of the examples of the present application had high barrier properties, and the peel height showing interlayer adhesion was dramatically improved as compared with that of the comparative example. The trunk haze was also within an allowable range. On the other hand, in Comparative Examples 1-3 and 8-10 which do not contain polyester (A) in a barrier layer, it turned out that the delamination height is low and interlayer adhesion is inferior. Further, in Comparative Examples 4 and 5 in which the inner layer and the outer layer did not contain polyamide (B), the barrier property was low, and the interlayer peeling height was low, so the interlayer adhesion was also low. In Comparative Example 6 having no barrier layer, the barrier property is remarkably low, and in Comparative Examples 7 and 11 in which the inner layer and the outer layer are made only of the polyester (A) and the barrier layer is made only of the polyamide (B), delamination is performed. The height was extremely low.

  The multilayer structure of the present invention has a high gas barrier property, does not easily cause delamination against dropping or external impact, is easy to handle, and can stably store contents, It is suitably used as a container for packaging a substance that hates oxygen, such as food, cosmetics and pharmaceuticals, or a preform thereof.

1 Inner layer 2, 2A, 2B Barrier layer 3 Outer layer 4 Intermediate layer

Claims (9)

A multilayer structure having at least a part of a multilayer structure including an inner layer, an outer layer, and at least one barrier layer positioned between the inner layer and the outer layer,
The inner layer and the outer layer are each independently 94 to 99.9% by mass of polyester (A) containing a dicarboxylic acid unit containing 80 mol% or more of terephthalic acid units and a diol unit containing 80 mol% or more of ethylene glycol units, and And a resin composition (C) containing 0.1 to 6% by mass of a polyamide (B) containing a diamine unit containing 70% by mole or more of a metaxylylenediamine unit and a dicarboxylic acid unit,
The barrier layer contains 1 to 40% by mass of a polyester (A) containing a dicarboxylic acid unit containing 80 mol% or more of terephthalic acid units and a diol unit containing 80 mol% or more of ethylene glycol units, and 70 metaxylylenediamine units. The multilayer structure which consists of a resin composition (D) containing 60-99 mass% of polyamides (B) containing the diamine unit and dicarboxylic acid unit which contain more than mol%.   The multilayer structure according to claim 1, wherein the polyamide (B) is a polyamide containing a diamine unit containing 70 mol% or more of metaxylylenediamine units and a dicarboxylic acid unit containing 70 mol% or more of adipic acid units.   The polyamide (B) is a polyamide containing a diamine unit containing 70 mol% or more of metaxylylenediamine units, and a dicarboxylic acid unit containing 70 to 99 mol% of adipic acid units and 1 to 30 mol% of isophthalic acid units. The multilayer structure according to claim 1 or 2, wherein   The polyester (A) comprises a dicarboxylic acid unit containing 80 to 99.9 mol% of terephthalic acid units and 0.1 to 10 mol% of metal sulfoisophthalic acid units, and a diol unit containing 80 mol% or more of ethylene glycol units. The multilayer structure as described in any one of Claims 1-3 which is polyester containing.   The multilayer structure according to any one of claims 1 to 4, which has at least a part of a three-layer structure including an inner layer / barrier layer / outer layer. It has a five-layer structure consisting of an inner layer / barrier layer / intermediate layer / barrier layer / outer layer at least in part,
94-99.9 mass% of polyester (A) in which an intermediate | middle layer contains the dicarboxylic acid unit which contains 80 mol% or more of terephthalic acid units, and the diol unit which contains 80 mol% or more of ethylene glycol units, and a metaxylylene diamine unit It consists of a resin composition (E) containing 0.1-6 mass% of polyamides (B) containing a diamine unit containing 70 mol% or more and a dicarboxylic acid unit, according to any one of claims 1 to 4. Multilayer structure.   The multilayer structure according to any one of claims 1 to 6, which is a preform.   The multilayer structure according to any one of claims 1 to 6, which is a container obtained by blow-molding a preform by a hot parison method or a cold parison method. The multilayer structure according to claim 7 or 8, which has a multilayer structure at least in a body portion.

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