JP2004160935A - Multilayered container - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a multilayered container which is not easily peeled off due to a fall and an impact and has excellent delamination resistance. <P>SOLUTION: Characteristically, this multilayered container includes outermost and innermost layers which are composed of a resin A, and at least one intermediate layer which is composed of a resin B; the resin A is predominantly composed of a thermoplastic polyester resin which is obtained by polymerizing an acid component containing a terephthalic acid of 80 mol% or more and a glycol component containing ethylene glycol of 80 mol% or more; the resin B is a gas barrier resin wherein an oxygen permeability coefficient of a three-times×three-times oriented film under the condition of 23°C-60%RH is less than 0.15 cc×mm/m<SP>2</SP>×day×atm; and the thickness of the resin B layer of a ground contact part of the container and the means thickness of the resin B layer of a body part of the container satisfy the specified relational expressions, respectively. <P>COPYRIGHT: (C)2004,JPO

Description

【００５０】
【発明の効果】
本発明によれば、優れた耐層間剥離性を有し、かつガスバリア性に優れた多層容器を得ることができ、本発明の工業的意義は大きい。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to the prevention of delamination of a multi-layer container, and more specifically, a multi-layer container having improved interlayer adhesion between an innermost and outermost layer and an intermediate layer when receiving a shock during transportation or dropping of the multi-layer container. It concerns a container.
[0002]
[Prior art]
At present, plastic containers (bottles) mainly composed of polyester such as polyethylene terephthalate (PET) are widely used for tea, fruit juice drinks, carbonated drinks and the like. The proportion of small plastic bottles is increasing year by year. Since the ratio of the surface area per unit volume increases as the bottle becomes smaller, the expiration date of the contents tends to be shorter when the bottle is made smaller. In addition, in recent years, beer that is easily affected by oxygen and light is sold in plastic bottles, and tea in plastic bottles is sold hot, and the range of use of plastic containers is expanding. Is required.
[0003]
In response to the above requirements, as a method of imparting gas barrier properties to a bottle, a multilayer bottle using a thermoplastic polyester resin and a gas barrier resin, a blended bottle, and a single layer bottle of a thermoplastic polyester resin, carbon coating, vapor deposition, application of a barrier resin. Barrier-coated bottles and the like have been developed.
[0004]
An example of a multi-layer bottle is to fill a mold cavity by injecting a thermoplastic polyester resin such as PET and a thermoplastic gas barrier resin such as polymetaxylylene adipamide (polyamide MXD6) that form the innermost and outermost layers. A bottle obtained by biaxially stretch-blow-molding a parison having a three-layer or five-layer structure obtained by the above method has been put to practical use.
[0005]
Further, a resin having an oxygen capturing function of capturing oxygen in a container while blocking oxygen from outside the container has been developed and applied to a multilayer bottle. As the oxygen-scavenging bottle, a multilayer bottle using polyamide MXD6 mixed with a transition metal-based catalyst as a gas barrier layer is preferable in terms of oxygen absorption rate, transparency, strength, moldability, and the like.
[0006]
The multilayer bottle is used for containers for beer, tea, carbonated drinks, etc. due to its good gas barrier properties. The use of multi-layer bottles in these applications will maintain the quality of the contents and improve shelf life, while delamination will occur between different resins, for example, between the innermost and outermost layers and the middle layer, reducing the commercial value. There is a risk of damage.
[0007]
As a method of solving such a problem, a backflow adjusting device capable of causing a certain amount of backflow toward the gas barrier layer side when the resin constituting the innermost and outermost layers is finally injected into the mold cavity is used. It has been proposed to improve the delamination resistance by introducing a coarse mixed resin between the layers (for example, see Patent Document 1), but there is a problem that a special device is used.
[0008]
[Patent Document 1]
JP 2000-254963 A
[0009]
[Problems to be solved by the invention]
An object of the present invention is to solve the above-mentioned problems, and to provide a multilayer container which is less likely to be separated by dropping or impact and has excellent delamination resistance.
[0010]
[Means for Solving the Problems]
The present inventors have conducted intensive studies on the delamination resistance of the multilayer container, and as a result, determined the barrier layer thickness ratio in the container grounding portion, and averaged the barrier layer thickness of the trunk from the vicinity of the container mouth plug to the grounding portion. It has been found that by defining the thickness ratio, it is possible to obtain a multilayer container capable of suppressing delamination without impairing the gas barrier properties, and reached the present invention.
[0011]
That is, the present invention relates to a multilayer container comprising an outermost layer and an innermost layer made of resin A and at least one intermediate layer made of resin B, wherein resin A contains an acid component containing terephthalic acid of 80 mol% or more and ethylene glycol. Is a thermoplastic polyester resin obtained by polymerizing a glycol component containing at least 80% by mole of a thermoplastic resin, and the resin B is a 3 × 3 stretched film which has an oxygen permeability at 23 ° C. and 60% RH. Coefficient is 0.15cc · mm / m²-Gas-barrier resin less than day-atm and thickness B of resin B layer at the container grounding portion_BbAnd the average thickness T of the resin B layer in the container body_BHowever, the present invention relates to a multilayer container characterized by satisfying the formulas (1) and (2), respectively.
(T_Bb/ T_Tb) <0.005 Expression (1)
(T_B/ T_T) / X> V_B/(0.15×A×T_T・ ・ ・ ・ ・ ・ Equation (2)
T_B; Average thickness of resin B layer in container body (cm)
T_Bb; Thickness (cm) of resin B layer in container grounding part
T_T; Average thickness of all layers in the container body (cm)
T_Tb; Thickness (cm) of all layers at the container grounding part
V_BThe amount of gas barrier resin used in the container (cm³)
A: Outer surface area of container (cm²)
X: oxygen permeability coefficient (cc · mm / m) of the resin B layer in the container body at 23 ° C. and 60% RH²・ Day ・ atm)
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
The multilayer container of the present invention is a multilayer container including an outermost layer and an innermost layer made of a resin (resin A) containing a thermoplastic polyester resin as a main component, and at least one intermediate layer made of a gas barrier resin (resin B). is there. As a specific layer configuration, for example, a three-layer configuration in which resin A, resin B and resin A are laminated in this order, or a resin A, resin B, resin A, resin B and resin A are laminated in this order A five-layer configuration is exemplified, but is not limited thereto. Further, a layer made of a resin other than the resin A and the resin B may be included. However, as will be described later, it is preferable to form only the resin A and the resin B because the two injection cylinders can be used for molding.
[0013]
The multilayer container of the present invention is obtained by blow molding a multilayer parison having the same layer configuration. For example, using an injection molding machine having two injection cylinders, a multilayer parison obtained by injecting resin A and resin B from each injection cylinder through a mold hot runner into a mold cavity is further used. Obtained by biaxial stretch blow molding.
[0014]
For example, in a method of manufacturing a multilayer parison by the above method, first, resin A is injected, then resin B and resin A are simultaneously injected, and then required amount of resin A is injected to fill the mold cavity. A parison having a three-layer structure (resin A-resin B-resin A) can be manufactured.
[0015]
Similarly, first, resin A is injected, then resin B is injected alone, and finally, resin A is injected to fill the mold cavity, thereby forming a five-layer structure (resin A-resin B-resin A-resin). Parisons having B-resin A) can be produced. The method for producing the multilayer parison is not limited to the above method.
[0016]
In the multilayer container of the present invention, the thickness of the resin B layer at the container grounding portion needs to satisfy Expression (1). At the same time, the average thickness of the resin B layer in the container body needs to satisfy the expression (2).
Here, the container grounding portion refers to a portion of the container that is in contact with the horizontal surface when the container is placed on a horizontal surface, and the layer thickness at the grounding portion is the average layer thickness at the portion. The container body portion refers to a body portion excluding the grounding portion and the bottom surface, and the layer average thickness is an average thickness in a region where the resin B layer exists. If there are a plurality of resin B layers, the total thickness is used.
(T_Bb/ T_Tb) <0.005 Expression (1)
(T_B/ T_T) / X> V_B/(0.15×A×T_T・ ・ ・ ・ ・ ・ Equation (2)
T_B; Average thickness of resin B layer in container body (cm)
T_Bb; Thickness (cm) of resin B layer in container grounding part
T_T; Average thickness of all layers in the container body (cm)
T_Tb; Thickness (cm) of all layers at the container grounding part
V_BThe amount of gas barrier resin used in the container (cm³)
A: Outer surface area of container (cm²)
X: oxygen permeability coefficient (cc · mm / m) of the resin B layer in the container body at 23 ° C. and 60% RH²・ Day ・ atm)
[0017]
In equation (1), (T_Bb/ T_Tb) Is less than 0.005, so that the interlayer adhesion between the layers when the multilayer container is transported or when it is subjected to an impact when dropped is improved, and the content of the content is satisfied by satisfying the expression (2). The container has gas barrier properties that meet the requirements.
[0018]
The resin A in the present invention is obtained by polymerizing an acid component containing terephthalic acid of 80 mol% or more, preferably 90 mol% or more, and a glycol component containing ethylene glycol of 80 mol% or more, preferably 90 mol% or more. The main component is a thermoplastic polyester resin.
Other acid components other than terephthalic acid include isophthalic acid, diphenylether-4,4-dicarboxylic acid, naphthalene-1,4 or 2,6-dicarboxylic acid, adipic acid, sebacic acid, decane-1,10-carboxylic acid. , Hexahydroterephthalic acid and the like can be used. Other glycol components other than ethylene glycol include propylene glycol, 1,4-butanediol, neopentyl glycol, diethylene glycol, cyclohexanedimethanol, 2,2-bis (4-hydroxyphenyl) propane, and 2,2-bis ( 4-Hydroxyethoxyfur) propane and the like can be used. Further, as a raw material monomer of the thermoplastic polyester resin (resin A), P-oxybenzoic acid, which is an oxyacid, may be used.
[0019]
Further, as the resin A, other thermoplastic resins can be blended with the thermoplastic polyester resin as long as the characteristics of the present invention are not impaired. Examples of other thermoplastic resins include polyolefin-based resins, polycarbonate, polyacrylonitrile, polyvinyl chloride, and polystyrene.
[0020]
Resin A has an intrinsic viscosity of 0.55 to 1.50, preferably 0.65 to 1.4. When the intrinsic viscosity is 0.55 or more, the multilayer parison can be obtained in a transparent amorphous state, and the mechanical strength of the obtained multilayer container can be satisfied. When the intrinsic viscosity is 1.5 or less, troubles in molding due to an increase in viscosity can be avoided.
[0021]
The gas barrier resin (resin B) constituting the intermediate layer in the present invention has an oxygen permeability coefficient of 0.15 cc · mm / m at 23 ° C. and 60% RH in a 3 × 3 stretched film.²A gas barrier resin having less than day.atm, for example, polyamide resin such as polyamide MXD6, polyvinyl alcohol resin, ethylene-vinyl alcohol copolymer resin, vinyl chloride copolymer resin, vinylidene chloride copolymer resin, acrylonitrile copolymer resin These resins may be used alone or as a mixture of two or more. Among them, polyamide resin and ethylene-vinyl alcohol copolymer resin are preferable, and polyamide MXD6 is particularly preferable.
Further, other thermoplastic resins may be mixed and used as long as the above oxygen permeability coefficient is satisfied.
[0022]
The polyamide resin is obtained by melt-polymerizing a diamine component and a dicarboxylic acid component, or by solid-phase polymerization after melt polymerization. In the polyamide MXD6, it is necessary that the diamine component contains at least 70 mol% of metaxylylenediamine. When the amount of meta-xylylenediamine in the diamine component is 70 mol% or more, excellent gas barrier properties can be maintained. Diamine components that can be used other than meta-xylylenediamine include para-xylylenediamine, 1,3-bis (aminomethyl) cyclohexane, 1,4-bis (aminomethyl) cyclohexane, tetramethylenediamine, hexamethylenediamine, and nonamethylenediamine , 2-methyl-1,5-pentanediamine and the like, but are not limited thereto.
[0023]
The dicarboxylic acid component in the polyamide MXD6 needs to contain adipic acid in an amount of 70 mol% or more. When the adipic acid content in the dicarboxylic acid component is 70 mol% or more, a decrease in gas barrier properties and a decrease in crystallinity can be prevented. Examples of dicarboxylic acid components that can be used other than adipic acid include suberic acid, azelaic acid, sebacic acid, 1,10-decanedicarboxylic acid, terephthalic acid, isophthalic acid, and 2,6-naphthalenedicarboxylic acid, but are not limited thereto. It is not done.
Also, a small amount of a monoamine or a monocarboxylic acid may be added as a molecular weight regulator during the polycondensation of the polyamide.
[0024]
The above polyamide resin is produced by a melt polycondensation method. As the melt polycondensation method, for example, there is a method in which a nylon salt composed of meta-xylylenediamine and adipic acid is heated in the presence of water under pressure and polymerized in a molten state while removing added water and condensed water. . It is also produced by a method in which meta-xylylenediamine is directly added to adipic acid in a molten state and polycondensed. In this case, in order to keep the reaction system in a uniform liquid state, meta-xylylenediamine is continuously added to adipic acid, and during this time, the reaction system is raised so that the reaction temperature does not fall below the melting points of the resulting oligoamide and polyamide. While heating, the polycondensation proceeds.
[0025]
The relative viscosity (1 g of a polyamide resin dissolved in 100 ml of a 96% aqueous sulfuric acid solution and measured at 25 ° C., the same applies hereinafter) of a relatively low molecular weight polyamide obtained by melt polymerization is usually about 2.28. When the relative viscosity after the melt polymerization is 2.28 or less, a high-quality polyamide having a low color tone and a good color tone can be obtained. The relatively low molecular weight polyamide obtained by melt polymerization is then subjected to solid state polymerization. Solid-state polymerization is performed by heating a polyamide having a relatively low molecular weight obtained by melt polymerization into pellets or powder, and heating the mixture to a temperature of 150 ° C. or higher and a melting point of the polyamide or lower under reduced pressure or an inert gas atmosphere. Will be implemented. The relative viscosity of the solid-phase polymerized polyamide is preferably 2.3 to 4.2. Within this range, molding into a multilayer container is good, and the performance of the obtained multilayer container, particularly, mechanical performance, is good. Although some effects of the present invention can be obtained even with a polyamide having a relatively low molecular weight after melt polymerization, the polyamide is not practical as a material for a multilayer container because the mechanical strength, particularly the impact resistance, is insufficient.
[0026]
Further, as the gas barrier resin (resin B) constituting the intermediate layer in the present invention, a polyamide obtained by polymerizing a diamine component and a dicarboxylic acid component, 90 to 99.9% by mass, and a layered silicate of 10 to 0.1% You may mix and use mass% by melt-kneading etc. and use it.
[0027]
As the layered silicate used in the present invention, a 1: 1 type layered silicate composed of one tetrahedral layer and one octahedral layer, that is, kaolinite, halloysite, chrysotile, etc., or two tetrahedral layers 2: 1 type layered silicate consisting of one octahedral layer, ie, smectites such as montmorillonite, hectorite, beidellite, savonite, mica such as muscovite, phlogovite, talc, pyrophyllite, vermiculite, chlorite And the like.
These layered silicates may be those which have been brought into contact with a swelling agent such as a polymer compound, an organic compound or an inorganic compound in advance to expand the interlayer.
[0028]
The addition amount of the layered silicate in the present invention is preferably 0.1 to 10% by weight, more preferably 0.2 to 5% by weight. If the added amount of the layered silicate is 0.1% by weight or more, the effect of improving gas barrier properties is exhibited, and if it is 10% by weight or less, transparency is not impaired.
[0029]
In the present invention, the layered silicate contained in the polyamide must be uniformly dispersed without local aggregation. The term “dispersion” as used herein means that layered silicates are separated into a plate shape in a polyamide, and 50% or more of them have an interlayer distance of 50 angstroms or more. The interlayer distance refers to the distance between the centers of gravity of the flat objects. The longer this distance, the better the dispersion state, the better the appearance such as transparency when finally made into a multilayer container, and the better the barrier property against gaseous substances such as oxygen and carbon dioxide.
[0030]
As for the method of melt-kneading the polyamide and the layered silicate, a method in which the layered silicate is added during the melt polymerization of the polyamide resin and stirred, or a method in which various kinds of commonly used extruders such as a single-screw or twin-screw extruder are used. A method of kneading, or a method in which a mixture in which a high-concentration layered silicate is added in advance to a polyamide, a so-called masterbatch, and then a method of melt-kneading the masterbatch and the polyamide, and the like, may be mentioned. The method is not limited.
[0031]
Further, as the gas barrier resin (resin B) constituting the intermediate layer in the present invention, a transition metal-based catalyst is used in an amount of 0.001 to 0.1% based on 100 parts by weight of a polyamide obtained by polymerizing a diamine component and a dicarboxylic acid component. It may contain 5 parts by weight.
[0032]
The transition metal-based catalyst used in the present invention is preferably a Group VIII metal component of the periodic table such as iron, cobalt and nickel, and other Group I metals such as copper and silver: tin, titanium and zirconium. Group IV metal, group V metal of vanadium, group VI metal such as chromium, and VII metal component such as manganese can be exemplified. Among these metal components, the cobalt component has a high oxygen absorption rate and is particularly suitable for the purpose of the present invention.
[0033]
The transition metal-based catalyst is used in the form of a low-valent inorganic acid salt, organic acid salt or complex salt of the transition metal. Examples of the inorganic acid salts include halides such as chlorides, oxyacid salts of sulfur such as sulfuric acid, oxyacid salts of acetate and nitrogen, phosphorus oxyacid salts such as phosphate, and silicates. On the other hand, examples of the organic acid salt include carboxylate, sulfonate, phosphonate, etc., and carboxylate is suitable for the purpose of the present invention. Specific examples thereof include acetic acid, propionic acid, and isopropylate. Ononic acid, butanoic acid, isobutanoic acid, pentanoic acid, isopentanoic acid, hexanoic acid, heptanoic acid, isoheptanoic acid, octanoic acid, 2-ethylhexanoic acid, nonanoic acid, 3,5,5-trimethylhexanoic acid, decanoic acid, neodecane Acid, undecanoic acid, lauric acid, myristic acid, palmitic acid, margaric acid, stearic acid, arachinic acid, lindelic acid, tuzunic acid, petroselinic acid, oleic acid, linoleic acid, linolenic acid, arachidonic acid, formic acid, oxalic acid, Transition metal salts such as sulfamic acid and naphthenic acid are exemplified. On the other hand, as the complex of the transition metal, a complex with β-diketone or β-keto acid ester is used, and as the β-diketone or β-keto acid ester, for example, acetylacetone, acetoacetate, 1,3-cyclohexyl, etc. Sadione, methylenebis-1,3-cyclohexadione, 2-benzyl-1,3-cyclohexadione, acetyltetralone, palmitoyltetralone, stearoyltetralone, benzoyltetralone, 2-acetylcyclohexanone, 2-benzoylcyclohexanone , 2-acetyl-1,3-cyclohexanedione, benzoyl-p-chlorobenzoylmethane, bis (4-methylbenzoyl) methane, bis (2-hydroxybenzoyl) methane, benzoylacetone, tribenzoylmethane, diacetylbenzoylmeta , Stearoylbenzoylmethane, palmitoylbenzoylmethane, lauroylbenzoylmethane, dibenzoylmethane, bis (4-chlorobenzoylmethane), bis (methylene-3,4-dioxybenzoyl) methane, benzoylacetylphenylmethane, stearoyl (4-methoxy Benzoyl) methane, butanoylacetone, distearoylmethane, acetylacetone, stearoylacetone, bis (cyclohexanoyl) -methane, dipivaloylmethane and the like can be used.
[0034]
In the multilayer container of the present invention, the transition metal-based catalyst is contained in an amount of 0.001 to 0.5 parts by weight, particularly 0.005 to 0.3 parts by weight, as a transition metal per 100 parts by weight of the gas barrier resin. Preferably, it is contained. If the amount of the transition metal-based catalyst is below the above range, the oxygen absorption rate is undesirably reduced as compared with the case within the above range. On the other hand, even if this amount exceeds the above range, the oxygen absorption rate is further improved. However, it is not preferable because there is a problem of deterioration and coloring of the resin during molding.
[0035]
In the present invention, if necessary, a colorant, an ultraviolet absorber, an antistatic agent, an antioxidant, a lubricant, a nucleating agent, an antibacterial agent, and the like can be blended with the resin A and the resin B and used.
[0036]
The multilayer container according to the present invention can suppress delamination without impairing gas barrier properties, is less likely to be separated by dropping or impact, and is not limited to a shape having less unevenness as in the past, and has a high degree of freedom in design. Can be increased.
[0037]
【Example】
Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples. In addition, a method for measuring main characteristics measured in the present example and the like will be described.
(1) Intrinsic viscosity [η] of polyethylene terephthalate (PET): A mixed solvent of phenol / tetrachloroethane = 6/4 (weight ratio) is used. Measurement temperature 30 ° C.
(2) Relative viscosity of polyamide MXD6 [ηrel. ]: 1 g of resin / 100 ml of 96% aqueous sulfuric acid solution, measurement temperature 25 ° C.
(3) Oxygen transmission rate: Model: OX-TRAN 2/20 manufactured by Modern Control Co., Ltd., 23 ° C., relative humidity 100% (inside the container), 50% RH (outside the container) according to ASTM D3985. It was measured under an atmosphere.
(4) Drop test: After putting 500 ml of water into the container and capping the container, the multilayer container left standing at 5 ° C. for 24 hours was dropped, and the presence or absence of delamination was visually checked. The multilayer container was dropped so that the bottom contacted the floor (vertical drop). Fall height 75, 100cm. Evaluation was based on the number of bottles that were delaminated when 100 bottles were dropped.
[0038]
Example 1
A multilayer parison and a multilayer hollow container were manufactured by the following method.
As resin A, PET having an intrinsic viscosity of 0.75, and as resin B, polyamide MXD6 having a relative viscosity of 2.70 (oxygen permeation coefficient at 23 ° C. and 60% RH in a 3 × 3 stretched film; 0.064 cc · mm / m²* Day * atm) was used.
For the production of the multilayer parison, an injection molding machine (model: M200, 4 pieces) manufactured by Meiki Seisakusho Co., Ltd. was used. Two injection cylinders were used for molding. The resin A is filled into the mold via the injection cylinder a, and the resin B is filled into the mold via the injection cylinder b.
Using the above resin, the resin A was first injected under the following conditions, a predetermined amount of the resin A was injected, then the resin B was injected simultaneously with the resin A, and then the resin A was injected to form a three-layer parison. .
Resin temperature in injection cylinder a: 280 ° C
Resin temperature in injection cylinder b: 270 ° C
Injection speed of injection cylinder b: 5.5 cm / sec
Resin channel temperature in mold: 280 ° C
Mold cooling water temperature: 15 ℃
The three-layer parison obtained by injection molding has a total length of 110 mm, an outer shape of 26.5 mmφ, a thickness of 4.5 mm, and a ratio of the resin B to the total weight of the parison is 5 wt%.
[0039]
The above three-layer parison was biaxially stretch blow-molded under the following conditions using a blow molding machine (manufactured by Krupp Corpoplast, Model: LB-01) to obtain a hollow three-layer container. The three-layer container has a total length of 223 mm, an outer diameter of 65 mm, an inner volume of 500 ml, and a bottom shape of a champagne type.
Parison heating temperature: 100 ° C
Blow pressure: 3.0MPa
[0040]
The obtained three-layer container exhibited the following performance, and satisfied both the expressions (1) and (2).
T_B; Average thickness of resin B layer in container body: 0.0031 cm
T_BbA thickness of the resin B layer at the container grounding portion: 0.00023 cm
T_TAverage thickness of all layers in container body: 0.042 cm
T_TbThe thickness of all layers at the container grounding portion: 0.064 cm
V_BUse amount of gas barrier resin in container: 1.14 cm³
A; outer surface area of container: 400 cm²
X: oxygen permeability coefficient of the resin B layer in the container body at 23 ° C. and 60% RH: 0.064 cc · mm / m²・ Day ・ atm
Formula (1): T_Bb/ T_Tb= 0.0036
Equation (2): (T_B/ T_T) /X=1.15, V_B/(0.15×A×T_T) = 0.45
[0041]
The obtained three-layer container was filled with water, and the delamination resistance was evaluated by a drop test. Further, the oxygen permeability of the container was measured to evaluate the oxygen barrier property.
The three-layer container showed good delamination resistance and oxygen barrier properties. Table 1 shows the results.
[0042]
Example 2
As the resin B, 97 parts by mass of a metaxylylene group-containing polyamide resin and 3 parts by mass of a layered silicate: “Orben” manufactured by Shiraishi Industry Co., Ltd. (using 34 wt% of a trimethyloctadecyl ammonium salt as a swelling agent) were used. After blending, the above-mentioned material is supplied at a rate of 6 kg / hr to a co-rotating twin-screw extruder having a cylinder diameter of 20 mmφ, melt-kneaded at a cylinder temperature of 270 ° C., extruded a strand from an extruder head, and cooled. A three-layer container was prepared in the same manner as in Example 1 except that the pelletized resin was used. Incidentally, the oxygen permeability coefficient at 23 ° C. and 60% RH of a stretched film 3 × 3 times the resin used as the resin B has a value of 0.028 cc · mm / m²* Day * atm.
[0043]
The obtained three-layer container exhibited the following performance, and satisfied both the expressions (1) and (2).
T_B; Average thickness of resin B layer in container body: 0.0035 cm
T_BbA thickness of the resin B layer at the container grounding portion: 0.00018 cm
T_TAverage thickness of all layers in container body: 0.042 cm
T_TbThe thickness of all layers in the container grounding portion: 0.061 cm
V_BUse amount of gas barrier resin in container: 1.14 cm³
A; outer surface area of container: 400 cm²
X: oxygen permeability coefficient of the resin B layer in the container body at 23 ° C. and 60% RH: 0.030 cc · mm / m²・ Day ・ atm
Formula (1): T_Bb/ T_Tb= 0.0030
Equation (2): (T_B/ T_T) /X=2.78, V_B/(0.15×A×T_T) = 0.45
[0044]
The obtained three-layer container was filled with water, and the delamination resistance was evaluated by a drop test. Further, the oxygen permeability of the container was measured to evaluate the oxygen barrier property.
The three-layer container exhibited good delamination resistance and excellent oxygen barrier properties. Table 1 shows the results.
[0045]
Example 3
Three layers were prepared in the same manner as in Example 1 except that a resin obtained by mixing 0.4 parts by weight of cobalt stearate and 0.04 parts by weight of cobalt atom with respect to 100 parts by weight of a metaxylylene group-containing polyamide was used as the resin B. A container was made. Incidentally, the oxygen permeability coefficient at 23 ° C. and 60% RH of a stretched film 3 × 3 times the resin used as the resin B is 0.005 cc · mm / m 2.²* Day * atm.
The obtained three-layer container exhibited the following performance, and satisfied both the expressions (1) and (2).
T_B; Average thickness of resin B layer in container body: 0.0033 cm
T_BbA thickness of the resin B layer at the container grounding portion: 0.00021 cm
T_TAverage thickness of all layers in container body: 0.042 cm
T_Tb; Total layer thickness at the container grounding portion: 0.055 cm
V_BUse amount of gas barrier resin in container: 1.14 cm³
A; outer surface area of container: 400 cm²
X: oxygen permeability coefficient of the resin B layer in the container body at 23 ° C. and 60% RH: 0.005 cc · mm / m²・ Day ・ atm
Formula (1): T_Bb/ T_Tb= 0.0038
Equation (2): (T_B/ T_T) /X=3.93, V_B/(0.15×A×T_T) = 0.45
[0046]
The obtained three-layer container was filled with water, and the delamination resistance was evaluated by a drop test. Further, the oxygen permeability of the container was measured to evaluate the oxygen barrier property.
The three-layer container exhibited good delamination resistance and excellent oxygen barrier properties. Table 1 shows the results.
[0047]
Comparative Example 1
A three-layer container was produced in the same manner as in Example 1, except that the injection speed of the injection cylinder b was set at 2.3 cm / sec.
The resulting three-layer container exhibited the following performance, satisfying expression (2) but not satisfying expression (1).
T_B; Average thickness of resin B layer in container body: 0.0025 cm
T_BbA thickness of the resin B layer at the container grounding portion: 0.00053 cm
T_TAverage thickness of all layers in container body: 0.045 cm
T_Tb; Total layer thickness at the container grounding portion: 0.061 cm
V_BThe amount of gas barrier resin used in the container: 0.96 cm³
A; outer surface area of container: 400 cm²
X: oxygen permeability coefficient of the resin B layer in the container body at 23 ° C. and 60% RH: 0.064 cc · mm / m²・ Day ・ atm
Formula (1): T_Bb/ T_Tb= 0.0087
Equation (2): (T_B/ T_T) /X=8.68, V_B/(0.15×A×T_T) = 0.36
[0048]
The obtained three-layer container was filled with water, and the delamination resistance was evaluated by a drop test. Further, the oxygen permeability of the container was measured to evaluate the oxygen barrier property.
The three-layer container exhibited good oxygen barrier properties, but had insufficient delamination resistance. Table 1 shows the results.
[0049]
[Table 1]

[0050]
【The invention's effect】
According to the present invention, a multilayer container having excellent delamination resistance and excellent gas barrier properties can be obtained, and the industrial significance of the present invention is great.

Claims (11)

A multilayer container comprising at least one outermost layer and innermost layer made of resin A, and at least one intermediate layer made of resin B, wherein resin A contains at least 80 mol% of an acid component containing terephthalic acid and at least 80 mol% of ethylene glycol. A resin mainly composed of a thermoplastic polyester resin obtained by polymerizing a glycol component containing a resin, wherein the resin B has a 0.15 cc oxygen permeability coefficient at 23 ° C. and 60% RH in a 3 × 3 stretched film. · ^mm / m is 2 · day · atm under the gas barrier resin, and the resin B layer thickness _{T Bb} in the container grounding portion, the resin B layer average thickness _{T B} of the container body portion, respectively formula (1) and A multilayer container satisfying (2).
(T _Bb / T _Tb ) <0.005 Expression (1)
(T _B / T _T ) / X> V _B /(0.15×A×T _T ) Equation (2)
T _B ; Average thickness of resin B layer in container body (cm)
T _Bb ; Resin B layer thickness (cm) at container grounding part
T _T ; average thickness of all layers in container body (cm)
T _Tb ; total layer thickness (cm) at the container grounding part
V _B ; amount of gas barrier resin used in the container (cm ³ )
A: Outer surface area of container (cm ² )
X: oxygen permeability coefficient of the resin B layer in the container body at 23 ° C. and 60% RH (cc · mm / m ² · day · atm) The multilayer container according to claim 1, wherein the resin B is a polyamide obtained by polymerizing a diamine component containing at least 70 mol% of metaxylylenediamine and a dicarboxylic acid component containing at least 70 mol% of adipic acid. Resin B has 90 to 99.9% by mass of polyamide obtained by polymerizing a diamine component containing 70 mol% or more of metaxylylenediamine and a dicarboxylic acid component containing 70 mol% or more of adipic acid, and a layered silicate of 10 to 0.9%. The multilayer container according to claim 1, comprising 1% by mass. Resin B is prepared by polymerizing a diamine component containing at least 70 mol% of meta-xylylenediamine and a dicarboxylic acid component containing at least 70 mol% of adipic acid with 100 parts by weight of a transition metal catalyst based on 100 parts by weight of a polyamide. The multilayer container according to claim 1, wherein the multilayer container contains 0.5 to 0.5 parts by weight. The multilayer container according to claim 1, wherein the resin B is an ethylene-vinyl alcohol copolymer resin. The multilayer container according to any one of claims 1 to 5, which is a three-layer container in which resin A, resin B, and resin A are laminated in this order. The multilayer container according to claim 6, wherein the three-layer container is obtained by blow molding a three-layer parison in which resin A, resin B, and resin A are laminated in this order. The three-layer parison fills each cylinder with resin A and resin B using an injection molding machine having two injection cylinders, and fills the resin in the order of resin A, resin A and resin B, and resin A. The multilayer container according to claim 7, which is obtained by injection molding in a mold cavity. The multilayer container according to any one of claims 1 to 5, which is a five-layer container in which resin A, resin B, resin A, resin B, and resin A are laminated in this order. The multilayer container according to claim 9, wherein the five-layer container is obtained by blow molding a five-layer parison in which resin A, resin B, resin A, resin B, and resin A are laminated in this order. The five-layer parison is filled with resin A and resin B in each cylinder using an injection molding machine having two injection cylinders, and the resin is injected into the mold cavity in the order of resin A, resin B, and resin A. The multilayer container according to claim 10, which is obtained by injection molding in the inside.