JP3096514B2 - Multilayer containers and packages - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming an optically anisotropic molten phase with a layer of a thermoplastic resin and improving gas barrier properties.
A laminate with a layer of copolymerized polyester having , preferably
Multilayer container made of heat oriented multilayer laminates were filled with contents into the vessel, Oyo preservability, thermoformability excellent package
And a method for producing the package .

[0002]

2. Description of the Related Art Polyester, especially polyethylene terephthalate (hereinafter sometimes abbreviated as PET), is
Because it has excellent properties such as hygiene, fragrance retention, and processability, soy sauce, seasonings such as sauces, juice, cola,
It is widely used as containers for soft drinks such as ramune, draft beer, cosmetics, and pharmaceuticals. Furthermore, in addition to the above-mentioned performance, since it is lighter than glass, has moderate pressure resistance, and has gas barrier properties, further growth as a substitute for glass bottles is expected in the future. However, lager beer and wine, which are expected to be the largest markets for glass bottles, have a longer shelf life, and carbonated beverages and other beverages have a smaller container, which increases the surface area of the container per unit volume. In order to further reduce the intrusion of oxygen from the atmosphere and the dissipation of carbon dioxide gas, there is a strong demand for improving the gas barrier properties of the container. It is extremely difficult to improve the gas barrier properties of PET itself because it is already at a very high level and it is necessary to improve the mechanical properties such as container molding performance and pressure resistance. It is.

Conventionally, various methods have been proposed for improving the gas barrier properties of PET containers. For example, a method of coating the inner and outer layers of the container with polyvinylidene chloride or the like, a method of forming a multilayer structure of 2 to 9 layers using an ethylene-vinyl alcohol copolymer, and the like have been proposed. In addition to conventional polyester molding equipment, equipment for coating and multi-layer containers is required, which is not only industrially disadvantageous, but also in the case of multi-layer containers due to the use of heterogeneous polymers, the point of easy delamination, Furthermore, there is an inconvenience in collecting and reusing used containers and incineration. Also, a method of manufacturing a container from a blend of different polymers such as polyester and nylon in advance has been proposed (JP-B-53-3361).
No. 8, JP-A-56-64839). In this case, the container can be manufactured with the existing equipment, but it is disadvantageous in that the physical properties of the container are deteriorated and that the container is recovered and reused.

In plastic containers, particularly under the condition where heat and moisture act simultaneously, such as in retort sterilization, which has recently been spotlighted as a food distribution form, the conventional PET container and ethylene-vinyl alcohol copolymer described above are used. Insufficient gas barrier properties have been pointed out in multi-layer containers containing one or more layers, and polyvinylidene chloride-based polymers have been used in view of more recent global environmental problems (recycling is not possible. Is not preferred.

On the other hand, a method using a so-called thermotropic liquid crystal polymer which forms an optically anisotropic molten phase as a gas barrier material has been proposed in recent years (Japanese Patent Application Laid-Open No. Sho 61).
-192762, JP-A-62-1119265, JP-A-62-187033, JP-A-64-45242,
JP-A-1-288421 and the like). Also, Polym. P
repr. (Am. Chem. Soc., Div. Po.
lym. Chem. ), 30 (1), 3-4 (198
In 9), the amount of oxygen gas permeated at 35 ° C. of a melt extruded film obtained from a thermotropic liquid crystal polymer produced from 40 mol% of polyethylene terephthalate and 60 mol% of 4-acetoxybenzoic acid is as follows. 36cc ・ 20
It is reported that μm / m ↑ 2 · day · atm.

Japanese Patent Publication No. 56-18016 discloses a compound represented by the formula -OC-R1-CO-O-R2-O- (where R1 is an alicyclic divalent radical having 4 to 20 carbon atoms; -40 aliphatic divalent radicals or C6-C16 aromatic divalent radicals having a carbonyl bond separated by at least 3 carbon atoms, R2 is an aliphatic divalent radical having 2-40 carbon atoms, An alicyclic divalent radical having 4 to 20 carbon atoms, an aromatic divalent radical having 6 to 20 carbon atoms, or a molecular weight of 200 to 200;
A method for producing a copolymerized polyester by reacting a polyester having a repeating unit represented by 8000 poly (alkylene oxide) divalent radicals) with an acyloxy aromatic carboxylic acid is disclosed.
Only acyloxybenzoic acids are specifically exemplified as acyloxyaromatic carboxylic acids.

[0007]

However, there are many problems when using the conventionally proposed thermotropic liquid crystal polymer as a molded product for an oxygen barrier. That is, the first problem is that molded products obtained from the conventionally proposed thermotropic liquid crystal polymer generally have high crystallinity, large mechanical property anisotropy, and small elongation. The point is that stretching is substantially impossible. Therefore, from such polymers, various molded articles for oxygen barrier, for example, films, sheets, bottles,
It is very difficult to form into cups, trays, bags and the like.

For this reason, Japanese Patent Application Laid-Open No. 62-187033 proposes a laminated stretch molded article having a layer made of a thermo (thermotropic) liquid crystal polyester and a layer made of a polyester containing a polyethylene terephthalate component on at least one surface thereof. Have been. In the publication, the thickness ratio of the layer made of polyester (which does not form optically anisotropic) to the layer made of thermo-liquid crystalline polyester is such that the polyester layer is 50 to 98% of the total thickness of the laminated stretch-formed product, It is disclosed that the thermal liquid crystal polyester layer is 2 to 50%, preferably 5 to 20%, and the thermal liquid crystal polyester layer is 50%.
It is described that when the above is the case, it is difficult to stretch as compared with the case where the polyester is stretched alone. On the other hand, there has been proposed a thermotropic liquid crystal polymer which gives a molded article having small anisotropy in mechanical properties. For example, JP-A-60-28428 discloses a terephthaloyl group,
A thermotropic liquid crystal polyester comprising a 3-dioxyphenylene group and a 2-substituted-1,4-dioxyphenylene group has been proposed. As described above, the moldability of the thermotropic liquid crystal polymer is improved by the introduction of the isoskeleton and the substituent, and it is not always sufficient, but the production of various molded articles is likely to be easy.

A second problem that may occur when the conventionally proposed thermotropic liquid crystal polymer is used as a molded product for an oxygen barrier is that molded articles obtained from the thermotropic liquid crystal polymer include: Oxygen barrier properties are not necessarily high enough. For example, Polym. Pre
pr. (Am. Chem. Soc., Div. Poly.
m. Chem. ), 30 (1), 3-4 (1989), a film obtained from a thermotropic liquid crystal polymer produced from 40 mol% of polyethylene terephthalate and 60 mol% of 4-acetoxybenzoic acid. Of oxygen gas permeation is 36 cc · 20 μm / m ↑ 2 · da
As reported to be y · atm, the polymer is at a level that is not necessarily a high performance oxygen barrier material. According to the study by the present inventors, it has been found that the oxygen barrier property of the film obtained from the thermotropic liquid crystal polyester described in JP-A-60-28428 is not always high.

Japanese Patent Application Laid-Open No. 61-89816 proposes a multilayer sheet and a multilayer film composed of a thermotropic liquid crystal polymer and a thermoplastic polymer. And the properties of the thermotropic liquid crystal polymer relating to gas barrier properties, moldability, and stretchability are not disclosed.Moreover, containers and containers using the thermotropic liquid crystal polymer are not disclosed. The technical idea of a food package obtained by filling the contents and further treating under the condition where heat and moisture simultaneously act is not disclosed. JP-A-2-253950 proposes a multilayer sheet and a multilayer film composed of a thermotropic liquid crystal polymer and a thermoplastic polymer, and their use in various packaging materials and retort foods, particularly utilizing gas barrier properties. No properties regarding stretchability are disclosed.

[0011]

In view of such a situation,
The present inventors have conducted intensive studies to provide a polyester multilayer container having excellent gas barrier properties and moldability that cannot be achieved by a conventional container made of a thermal liquid crystal polymer, and as a result, completed the present invention. Reached. That is, the present invention comprises at least one layer mainly composed of a thermoplastic resin ,
In effect,

[0012]

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(Wherein Ar represents a 1,4-phenylene group or a 2,6-naphthylene group), a structural unit (1) represented by the following formula:

[0014]

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Structural unit (2) represented by the following formula:

[0016]

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Which comprises the structural unit (1) and the structural unit (2) in a substantially equal number of moles, and the total amount of the structural unit (1) and the structural unit (2) Is 15 to 90 mol%, the amount of the structural unit (3) is 10 to 85 mol% , and the oxygen permeation amount is 20 cc · 20 μm / m.
Multilayer container, characterized by comprising a laminate of a layer of heat-crystal polyester is ² · day · atm or less, the heating extension
The multilayer container comprising a stretched multilayer laminate, a package in which the multilayer container is filled with contents , and the multilayer container
After filling the contents and sealing, treat with hot water or steam.
A method for producing a package, characterized in that:

The term "container" used in the present specification means a molded article suitable mainly for packaging of foods and drinks, pharmaceuticals and the like. Such molded articles include sheets and films made of the multilayer polyester of the present invention, as well as bottomed containers such as bottles, trays, cups, and bags.

Hereinafter, the present invention will be described specifically. The structural unit (1) of the thermal liquid crystalline polyester used in the present invention is a structural unit introduced by an aromatic dicarboxylic acid component,
Specifically, it is a terephthaloyl group and / or a naphthalene-2,6-dicarbonyl group. Part of the structural unit (1), preferably 20 mol% or less of the structural unit (1), may be replaced by another dicarboxylic acid component. As other dicarboxylic acid components, for example, isophthalic acid,
2,7-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid,
Those corresponding to dicarboxylic acids such as succinic acid, adipic acid and sebacic acid can be mentioned. In addition, if the amount of the obtained polyester is within the range that enables melt molding, a part of the structural unit (1) can be replaced with a polycarboxylic acid component such as trimellitic acid, trimesic acid, and pyromellitic acid. is there.

The structural unit (2) in the thermal liquid crystalline polyester used in the present invention is an ethylenedioxy group introduced by ethylene glycol, and a part thereof, preferably 20 mol of the structural unit (2). % Or less may be replaced by a structural unit that can be introduced by another glycol. Examples of glycols other than ethylene glycol include 1,2-propanediol, 1,3
-Propanediol, 1,4-butanediol, 1,3
-Butanediol, 2-methyl-1,3-propanediol, 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 3-methyl-1,5
-Pentanediol, 1,4-cyclohexanedimethanol, diethylene glycol, triethylene glycol, o-, m- or p-xylylene glycol. Further, if the amount of the obtained polyester is within a range in which the polyester can be melt-molded, a part of the structural unit (2) is
It is also possible to substitute a structural unit that can be introduced by a polyhydric alcohol such as glycerin, trimethylolpropane, triethylolpropane, and pentaerythritol.

The structural unit (1) and the structural unit (2) in the thermal liquid crystalline polyester used in the present invention are a reaction mainly composed of terephthalic acid or its ester-forming derivative and ethylene glycol, 2,6-naphthalene Reaction based on dicarboxylic acid or an ester-forming derivative thereof and ethylene glycol as a main component, or a mixture of terephthalic acid and 2,6-naphthalenedicarboxylic acid, or a reaction based on an ester-forming derivative thereof and ethylene glycol as a main component By using the polyester obtained by the above as one of the raw materials, the polyester is introduced into the molecules of the thermal liquid crystal polyester in the present invention.

The polyethylene terephthalate, polyethylene naphthalate or a copolymer thereof used in the production of the thermal liquid crystalline polyester in the present invention can be produced by a method which has been established for the production of conventional polyesters such as polyethylene terephthalate. For example, it can be obtained by a method of subjecting a dicarboxylic acid and a glycol to an esterification reaction followed by polycondensation, a method of subjecting a dicarboxylic acid ester and a glycol to interesterification and then a polycondensation. In this case, it is sometimes preferable to use an esterification catalyst, a transesterification catalyst, a polycondensation catalyst, a stabilizer, and the like.However, as these catalysts, stabilizers, and the like, in the production of polyester, particularly polyethylene terephthalate, What is known as a usable catalyst, stabilizer and the like can be used. For example, catalysts that promote these reactions include sodium, magnesium, calcium, zinc, manganese, tin, tungsten,
Metal compounds such as germanium, titanium, antimony,
Examples of the stabilizer include phosphorus compounds such as phosphoric acid, phosphoric acid esters, phosphorous acid, and phosphites. Further, if necessary, other additives (colorant, ultraviolet absorber, light stabilizer, antistatic agent, flame retardant,
(A crystallization accelerator, etc.) can also be added.

The degree of polymerization of the raw material polyester such as polyethylene terephthalate, polyethylene naphthalate and copolymers thereof used in producing the thermal liquid crystalline polyester used in the present invention is not particularly limited, but phenol / tetrachloroethane is used. 30 in an equal weight mixed solvent
It is desirable to use one having an intrinsic viscosity of 0.01 to 1.5 dl / g measured at ° C.

The structural unit (1) and the structural unit (2) are
In their total amount, 15 to 9
It is present in the range of 0 mol%, preferably in the range of 25-85 mol%, more preferably in the range of 30-80 mol%.

On the other hand, the structural unit (3) in the thermal liquid crystalline polyester used in the present invention is a 6-oxy-2-naphthoyl group. Part of the structural unit (3), preferably 10
The mole% or less may be replaced by another hydroxycarboxylic acid component. Examples of the hydroxycarboxylic acid component other than the 6-oxy-2-naphthoyl group include 7-
Oxynaphthoyl groups such as an oxy-2-naphthoyl group, a 4-oxy-1-naphthoyl group and a 5-oxy-1-naphthoyl group are exemplified.

In the thermal liquid crystalline polyester used in the present invention, the content of the structural unit (3) is suitably in the range of 10 to 85 mol%, more preferably 15 to 75 mol%, and further preferably 20 to 85 mol%. ~ 70 mol%. When the content of the structural unit (3) exceeds 85 mol%, disadvantages such as difficulty in melt polymerization and remarkable impairment of the moldability occur. Since no liquid crystal is formed, the gas barrier property is greatly reduced, which is not preferable.

The structural unit (3) in the thermal liquid crystalline polyester used in the present invention is usually introduced into a polymer molecule by using a corresponding acyloxycarboxylic acid as a raw material. As the acyloxycarboxylic acid, acetoxycarboxylic acid obtained by reacting the corresponding hydroxycarboxylic acid with acetic anhydride is preferable.

The thermal liquid crystalline polyester used in the present invention has a property of forming a liquid crystal (having optical anisotropy) in a molten phase. Confirmation of such optical anisotropy in the molten phase, as is well known to those skilled in the art, using a polarizing microscope equipped with a heating device, under crossed Nicols, preferably 5-20 μm This can be done by observing a thin slice of a degree between the cover glasses at a constant heating rate and observing that light is transmitted at a certain temperature or higher. In this observation, the transmission of polarized light can be observed more reliably by applying light pressure to the sample sandwiched between the cover glasses at a high temperature or by sliding the cover glass. In this observation, the temperature at which polarized light starts to pass is the transition temperature to an optically anisotropic molten phase. It is desirable that the transition temperature be 350 ° C. or lower, more preferably 300 ° C. or lower, from the viewpoint of ease of melt molding.

The transition temperature of the thermal liquid crystalline polyester in the present invention to an optically anisotropic molten phase is difficult to determine by a differential scanning calorimeter, unlike the conventionally proposed thermal liquid crystalline polyester. That is, as is clear from the examples below, when the thermal liquid crystal polyester in the present invention is measured by a differential scanning calorimeter, a clear endothermic peak may not be observed depending on the composition, and an endothermic peak may be observed, for example. In that case, the peak is not necessarily based on the transition from the crystal to the liquid crystal. In the thermal liquid crystalline polyester of the present invention, the endothermic peak becomes smaller as the ratio of the structural unit (3) increases, and the ratio of the structural unit (3) becomes 3
Above 5 mol%, the endothermic peak is often not observed.

The production of the thermo-liquid crystalline polyester in the present invention comprises:
For example, preparing a polyester fragment by first acidifying polyethylene terephthalate, polyethylene naphthalate, a copolymer thereof or a mixture thereof with 6-acyloxy-2-naphthoic acid, and subsequently increasing the degree of polymerization of the polyester fragment This is carried out by a method of preparing a desired thermal liquid crystal polyester. The first stage acidosis is
Usually, the reaction is performed at 250 to 300 ° C. in an atmosphere of an inert gas such as nitrogen, argon or carbon dioxide.

As the starting compound, 6-acyloxy-2-
Instead of naphthoic acid, 6-hydroxy-2-naphthoic acid can also be used. In that case, 6-hydroxy-2-naphthoic acid and a lower aliphatic acid anhydride, preferably acetic anhydride, were reacted to convert (acylate) substantially all hydroxyl groups into acyloxy groups, preferably acetoxy groups. Thereafter, without isolating the corresponding acyl ester produced, it is reacted with a predetermined raw material polyester to produce the thermal liquid crystal polyester in the present invention. In this case, the raw material polyester is 6-hydroxy-
It can be added to the system at any time before and after the acylation reaction of 2-naphthoic acid. In the 6-hydroxy-2-naphthoic acid acylation reaction step, the 6-acyloxy-2-naphthoic acid produced as the reaction proceeds may precipitate in the system, making stirring difficult. A solvent that does not adversely affect the desired acylation reaction and has a boiling point of about 100 to 200 ° C.
It is particularly desirable that acetic acid be present in the system.

Most of the theoretical distillate of the lower aliphatic acid generated in the acidolysis reaction between the 6-acyloxy-2-naphthoic acid and the raw material polyester goes out of the system. Next, the product of the acidolysis reaction remaining in the system is removed under reduced pressure for 250 minutes.
Further de-lower aliphatic acids at ~ 350 ° C increase the degree of polymerization to a logarithmic viscosity suitable for shaping the desired article, preferably greater than or equal to 0.1 dl / g. In this case, the polymerization temperature is preferably 270 ° C. or higher from the viewpoint of the reaction rate and 350 ° C. or lower from the viewpoint of suppressing the decomposition of the polyester, and particularly preferably 270 to 320 ° C. In this polymerization step, the degree of reduced pressure is gradually increased, and it is desirable that the pressure is finally reduced to 1 mmHg or less, preferably 0.5 mmHg or less. Further, as a method for further increasing the molecular weight, a solid phase polymerization method well known in the art can be used.

The thermal liquid crystalline polyester used in the present invention comprises:
The logarithmic viscosity measured at 60 ° C. in pentafluorophenol is 0.1 dl in view of the mechanical strength of the obtained molded article.
/ G or more, preferably 0.3 dl / g or more, more preferably 0.4 dl / g or more. Also,
Although there is no critical upper limit for the logarithmic viscosity, it is preferably not more than 3.0 dl / g, and more preferably not more than 2.0 dl / g from the viewpoint of ease of melt polymerization, moldability and the like.

Regarding the composition ratio of the structural units (1), (2) and (3) of the thermal liquid crystalline polyester used in the present invention, the polymer was dissolved in an appropriate solvent, and the NMR spectrum of the solution was measured. And a polymer having substantially the same composition as the raw material composition ratio is usually obtained.

The thermal liquid crystal polyester in the present invention is different from a conventionally known thermal liquid crystal polymer in that the molded product obtained by quenching from a molten state has a very low crystallinity, and is usually obtained by X-ray diffraction. The crystallinity is not more than 20%. The crystallinity decreases as the proportion of the structural unit (3) in the thermal liquid crystal polyester increases. For this reason, a molded article such as a film form obtained from the thermo-liquid polyester in the present invention is different from the conventionally proposed thermo-liquid polyester, and can be heated and stretched in uniaxial and biaxial directions as described later. Yes, in many cases, simultaneous or sequential biaxial stretching of 2 × 2 times or more or 3 × 3 times or more is possible. Moreover, the molded article made of the thermo-liquid crystalline polyester of the present invention has excellent gas barrier properties. Furthermore, as is clear from the examples below, the molded articles obtained from the thermo-liquid crystalline polyester of the present invention have conventionally been proposed with respect to mechanical properties such as flexural strength and flexural modulus despite low crystallinity. It is significantly larger than that of the molded article obtained from the liquid crystalline polyester.

The thermal liquid crystalline polyester in the present invention can be melt-molded by a conventionally known method with respect to ordinary polyesters, whereby various molded products can be obtained. The film obtained from the thermo-liquid crystalline polyester in the present invention is transparent depending on its thickness.
Many films having a thickness of 5 μm have sufficient transparency. Providing such a transparent film is also a feature of the polyester of the present invention, which is not found in the conventional thermal liquid crystal polyester.

Another requirement of the present invention is that it comprises a laminate of the layer of the thermo-liquid crystalline polyester and at least one layer mainly composed of a thermoplastic resin. By laminating a layer of a thermoplastic resin on the layer of the thermo-liquid crystal polyester, a package excellent in gas barrier properties, hot water resistance, retort resistance, and thermoformability can be obtained.

As the resin forming the layer mainly composed of a thermoplastic resin, a thermoplastic resin having a glass transition temperature (Tg) of 170 ° C. or less is suitably used. Especially Tg15
A thermoplastic resin of 0 ° C. or lower is preferred. Here, Tg
Is a value obtained by DSC (measured at a heating rate of 10 ° C./min). A typical example is a hydrophobic resin, particularly a polyolefin resin. As the polyolefin resin, high-density, medium-density or low-density polyethylene, polypropylene, vinyl acetate, acrylate, or butene, hexene, polyethylene copolymerized with α-olefins such as 4-methyl-1-pentene, Ionomer resin, polypropylene homopolymer,
Polypropylene graft copolymerized with ethylene, or polypropylene copolymerized with α-olefins such as ethylene, hexene and 4-methyl-1-pentene, poly-1-butene, poly-4-methyl-1-pentene, or And a modified polyolefin obtained by reacting maleic anhydride or the like with the polyolefin described above, and an ethylene-vinyl alcohol copolymer. Among them, polypropylene (PP) is suitable for the purpose of the present invention.

Further, as a resin forming a layer mainly composed of a thermoplastic resin, poly (ethylene terephthalate),
Polyester resins such as poly (ethylene naphthalate), poly (butylene terephthalate), poly (ethylene terephthalate / isophthalate), and polystyrene resins such as polystyrene, styrene-butadiene copolymer, and styrene-isoprene copolymer Or, polyamide resins such as polycarbonate resin, nylon 6, nylon 66, nylon 6/12 copolymer, nylon 6 / 6,6 copolymer and the like can be mentioned.

Further, the resin forming the layer mainly composed of a thermoplastic resin may be used alone or in combination of two or more kinds. In addition, inorganic fillers such as talc, mica, clay, sericite, glass flake, calcium carbonate, silicic acid, and titanium may be added as long as the formability is not impaired.

In laminating the layer mainly composed of the above-mentioned thermoplastic resin on the layer composed of the polyester, one of the inner layer and the outer layer of the layer composed of the polyester is used.
It is an essential requirement to be laminated on the layers, and more preferably on the inner and outer layers. In particular, in order to impart hot water resistance and retort resistance, it is effective to be laminated on the inner and outer layers. When laminated on the inner and outer layers, the resin forming the inner and outer layers may be the same or different. Further, a plasticizer, a lubricant, an antioxidant, a colorant, an ultraviolet absorber or the like or another polymer may be added as long as the function and effect of the present invention are not impaired.

In the present invention, a multilayer laminate comprising at least one layer mainly composed of the above-mentioned thermoplastic resin and the polyester layer and a sealed container using the multilayer laminate can be produced by a conventionally known method. Particularly, it is suitably used for a heat-stretched multilayer laminate. In the co-extrusion method, after melt-kneading in an extruder corresponding to each resin layer, the resin layer is extruded into a predetermined shape through a multilayer multiple die such as a T-die or a circular die. In the co-injection method, after melt-kneading with an injection machine corresponding to each resin layer, the mixture is injected into a mold to produce a multilayer container or a preform for the container. In the dry lamination method, the polyester resin in the present invention is melt-kneaded with an extruder, and then is extruded from a molding die such as a T-die or a circular die, and a film obtained mainly by a thermoplastic resin is used as a sheet. And a sheet are laminated to produce a multilayer laminate. In laminating, both films and sheets may be stretched. In addition, a multilayer laminate is manufactured by a sand lamination method or an extrusion lamination method. For the layer mainly composed of a thermoplastic resin in the co-extrusion method, scrap generated when the multilayer container of the present invention is produced can be used as a raw material or a part of the raw material. Further, the scrap can be used as a layer independent of at least one layer mainly composed of a thermoplastic resin and the polyester layer.

When the layers of the multilayer container of the present invention are prepared by a coextrusion method, an adhesive resin layer is sandwiched between at least one layer mainly composed of a thermoplastic resin and the polyester layer. The usual method of laminating is employed. The adhesive resin is not particularly limited as long as it does not cause delamination at a practical stage. For example, an unsaturated carboxylic acid or an anhydride thereof may be an olefin-based polymer (eg, polyethylene, polypropylene, polybutene, etc.). Polyolefin, olefin-based copolymer)
And a modified olefin polymer containing a carboxyl group, which is obtained by chemically (e.g., addition reaction, graft reaction). Specifically, maleic anhydride graft-modified polyethylene, maleic anhydride graft-modified polypropylene, maleic anhydride graft-modified ethylene-
One or two kinds of mixtures selected from an ethyl acrylate copolymer and a maleic anhydride graft-modified ethylene-vinyl acetate copolymer are exemplified. Further, glycidyl acrylate, a polymerizable unsaturated compound having a glycidyl group such as glycidyl methacrylate, a polymerizable unsaturated compound having a methacryloxypropyltrimethoxysilane group, a glycidyl group, a modified olefin polymer such as an alkoxysilane group. Can be These functional groups may be used in combination. Specifically, glycidyl-modified polyethylene, glycidyl-modified polypropylene, glycidyl-modified ethylene-ethyl acrylate copolymer, glycidyl-modified ethylene-vinyl acetate copolymer, alkoxysilane-modified polyethylene, alkoxysilane-modified polypropylene,
One or two kinds of mixtures selected from alkoxysilane-modified ethylene-vinyl acetate copolymers are exemplified. In addition, a polyester resin containing a polyvalent carboxylic acid, a polyhydric alcohol, or a hydroxycarboxylic acid as a component is also exemplified as the adhesive resin.

When the dry laminating method is employed, the adhesive for dry laminating is not particularly limited as long as the interlayer adhesive strength is sufficient. For example, polyurethane-based and polyester-based adhesives for dry lamination are mentioned. In lamination, a corona discharge treatment, a sputtering treatment, a high-frequency treatment, a flame treatment, a chromic acid treatment, a solvent etching treatment and the like, or a surface treatment combining these may be performed.

The laminate produced by these methods takes the form of a sheet, film, parison, preform, or the like, and the laminate is reheated at a predetermined temperature by vacuum pressure forming, biaxial stretching blow molding, or the like. And a method of subjecting the multilayer laminate (sheet, film) to a biaxial stretching machine and performing a heating and stretching operation, and a method of stretching and blowing a parison or preform obtained by a co-injection method. It is formed in a container having a predetermined shape.

Further, with respect to the multilayer container of the present invention, the average thickness of all the layers of the body wall is 40 to 2500 μm, particularly 250 μm.
The thickness ratio of the polyester layer to the total layer thickness is not particularly limited.
50%, preferably 1 to 30%, particularly preferably 2 to 2
0%.

When the thermoplastic resin layer is A and the polyester layer is B, the layer structure of the multilayer container of the present invention is as follows.
/ B, A / B / A, A / B / A / B, A / B / A / B /
A and the like. The adhesive resin layer described above and the recovery layer of the multilayer container of the present invention can be arranged in each interlayer.

In the present invention, as described above, the heat-stretched multilayer laminate is a container or sheet such as a cup or a bottle obtained by heat-stretching, or a film-like material. This means an operation in which the multilayer laminate is left at a temperature required for stretching for a predetermined time and the multilayer laminate becomes substantially uniform thermally. Considering the operability, a method of heating and uniformizing with various heaters is preferable.

The heating operation may be performed simultaneously with or before the stretching. In addition, the heating operation means that a multilayer laminate that has been thermally uniformly heated is chucked, plugged,
It means an operation of uniformly forming a cup, a bottle, or a film by a vacuum force, a pneumatic force, or the like, and any of uniaxial stretching, simultaneous biaxial stretching, and sequential biaxial stretching can be employed.

The stretchability of the thermal liquid crystalline polyester in the present invention will be described. Films and sheets obtained by extrusion-molding the thermo-liquid crystalline polyester from a molding die such as a T-die or a circular die by a conventionally known method are subjected to a heat stretching operation to increase the area by 1.3 times or more as compared with that before stretching. It is an essential requirement to achieve the present invention that the magnification is preferably at least 4 times, more preferably at least 9 times. Here, the stretching temperature is the glass transition temperature of the thermo-liquid crystalline polyester + 10
C. to glass transition temperature + 150.degree. C. or glass transition temperature + 10.degree. C. to melting point, preferably glass transition temperature + 3.
The range is from 0 ° C. to the glass transition temperature + 130 ° C. or the glass transition temperature + 30 ° C. to the melting point, and the glass transition temperature and the melting point are values obtained by thermal analysis according to a method described later.
When the stretchability of the film or sheet obtained from the thermo-liquid crystal polyester in the present invention is less than 1.3 times, a multilayer comprising the thermo-liquid polyester layer in the present invention and a layer mainly composed of a thermoplastic resin. Even if an attempt is made to obtain a multilayer container from the laminate, the layer of the thermo-liquid crystalline polyester is broken and a desired container cannot be obtained.

The thermal liquid crystal polyester of the present invention has excellent oxygen barrier properties, has a performance 20 to 400 times or more that of polyethylene terephthalate, and has a very small humidity dependence of the excellent oxygen barrier properties. . For example, the thermal liquid crystal polyester in the present invention usually has an oxygen transmission rate measured at 20 ° C. of 20 cc · 20 μm / m ／ 2 · d.
Provides a quenched film with ay · atm or less. The oxygen barrier property may be further improved by subjecting the molded article to heat treatment.

The thus obtained multilayer container of the present invention comprises:
After filling the contents, especially food, the inside is degassed by known means if necessary, or nitrogen gas, after replacing the inside with an inert gas such as carbon dioxide gas, sealing by means such as heat sealing, Subsequently, it is sterilized by hot water or steam (especially high-temperature, high-pressure steam sterilization) such as a so-called boil treatment at 100 ° C. or lower or a retort treatment carried out at a temperature condition exceeding 100 ° C., especially at 105 to 135 ° C. Thus, the package of the present invention, in particular, a food package is obtained.
Here, as the boil sterilization treatment or the retort sterilization treatment, ordinary hot water or steam heat treatment conditions can be adopted. For the retort sterilization treatment, various methods such as a recovery type, a replacement type, a shower type, a spray type and the like are adopted.

When the multilayer container of the present invention is a cup or tray type container, a particularly excellent food package is obtained.

The contents to be filled are mainly foods. Here, as food, you can eat it as it is,
Cooked or semi-cooked foods that are warmed prior to eating are suitable. Next, examples of sterilized foods will be described. Cooked curry, cooked bean sprouts, beef stew, borscht, meat sauce, sour pork, sukiyaki, chinese bean, happo, meat, potato, oden, asparagus boiled, sweet corn, mushroom, tuna cream boiled, consommé,
Various soups such as potage, miso soup, pork juice, kenchin soup, rice, pot rice, fried rice, pilaf, porridge, spaghetti,
Additive foods such as buckwheat, udon, ramen, noodles, kamamai-no-moto, Chinese buckwheat noodles, etc. , Yakiniku, yakitori, roast chicken, pork ketchup, fish meat, bacon, kamaboko, pudding, jelly, yokan, various pet foods, and the like.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited thereto. Parts mean parts by weight.

[0056]

EXAMPLES The measurement of physical properties, the moldability and the evaluation of retort in this example were performed according to the following methods. (1) Logarithmic viscosity (ηinh) 0.1 g / dl using a pentafluorophenol solvent
At 60 ° C. ηinh = ln (t1 / t0) / c [wherein, ηinh represents a logarithmic viscosity (dl / g), t0 represents a flow time in a solvent (second), and t1 is a flow time in a sample solution (second). Represents the concentration of the sample in the solution (0.1 g
/ Dl). (2) Thermal analysis Differential scanning calorimeter (DSC; manufactured by Mettler, TA-300)
0), the sample was quenched from the molten state.
The melting point (Tm) and glass transition temperature (Tg) were measured at a heating rate of 0 ° C./min. (3) Oxygen Permeation (OTR) Gas Permeability Measurement System (MODERN CONTROL)
S company OX-TRAN10 / 50A)
It measured about the blown film under conditions of ° C and 65% of relative humidity. The unit is cc ・ 20μm / m ↑ 2
* Day * atm. (4) Stretchability A single-layer film is formed by an inflation film forming method.
This film was 3 × 3 times (area 9 times) at a temperature of 100 to 200 ° C. using a biaxial stretching device manufactured by Toyo Seiki Seisaku-sho, Ltd.
For biaxial stretching. (5) Thermoformability The external appearance was visually evaluated using a vacuum pressurized air molding machine manufactured by Asano Laboratory (drawing ratio: 1/1, round bottom cup, heater temperature: 400 ° C.). (6) Retort test Using the container prepared in (5), a sealed container filled with corn beef as a test sample was used as a test sample, and a retort apparatus (Hisaka Manufacturing Co., Ltd., high temperature and high pressure cooking sterilization tester RCS-). (40RTGN), a retort treatment at 120 ° C. for 60 minutes was performed, and a sensory test such as a change in taste was performed. (7) Polymer composition The obtained polymer was used as a trifluoroacetic acid solution, and 500
MHz 1H-NMR (manufactured by JEOL, JNM GX-50
0). As a result of the measurement, it was confirmed that the constituent compositions of the thermal liquid crystal polyesters obtained in the examples and the comparative examples were consistent with the composition of the charged raw materials within the analytical accuracy in each case.

Example 1 975 g (4.0 mol) of polyethylene naphthalate having an intrinsic viscosity of 0.65 dl / g measured at 30 ° C. using a phenol / tetrachloroethane equal weight mixed solvent, and 6-acetoxy-2-naphthoe 1390 g (6.0 mol) of acid was charged into a reactor having an internal volume of 8 liters equipped with a stirrer, a distillation column and a nitrogen gas inlet, and the inside of the reaction system was replaced with nitrogen three times, and then at 290 ° C. for 1 hour under a nitrogen stream. The mixture was stirred and heated, and then the pressure inside the system was gradually reduced, and the reaction was carried out at about 30 mmHg for about 2 hours. As a result of this operation, about 90% of the theoretical amount of acetic acid distilled out. Next, the degree of vacuum in the reaction system was further increased, and the reaction was carried out at 1 mmHg or less for 5 hours, and then the produced polyester (polymer A) was taken out.

The obtained polymer was dissolved in trifluoroacetic acid and 1 H-NMR spectrum was measured. As a result, the structural unit ratio of the present polymer was [(constituent unit (1) + constituent unit (2)] / constituent unit (3)). Was found to be 57/43 in molar ratio. This is substantially the same as the charged raw material composition ratio. A small piece of the resulting polymer is
nkam) The temperature was raised at a rate of 10 ° C./min in a nitrogen atmosphere in a heating apparatus for microscopes TH-600 at a rate of 10 ° C./min. As the temperature rose, the amount of transmitted light further increased, and even when the temperature was finally raised to 350 ° C., an optically anisotropic molten phase was still formed. In addition, as a result of analyzing a sample obtained by rapidly cooling the polymer from a molten state by a DSC at a heating rate of 10 ° C./min, a glass transition point was observed at 88 ° C.
No endothermic peak was observed. Furthermore, the crystallinity of a sample obtained by quenching the polymer from the molten state was measured by X-ray wide-angle scattering. As a result, the crystallinity was 8%. Next, a small injection molding machine (TK14-1A) manufactured by Tabata Machine
(P type), cylinder temperature 280 ° C, injection pressure 8
00kg / mm ↑ 2, 75 × 15 × 2 at mold temperature 30 ° C
A test piece having a size of mm was prepared. The obtained test piece is J
When the flexural strength and flexural modulus were measured by a method according to IS K7203, the following results were obtained (in each case, the flow direction of the resin).

Flexural strength 2138 kg / cm
$ 2

Flexural modulus 12.9 × 10 ↑ 4
kg / cm ↑ 2

Next, the present polymer prepared by a scale-up facility (the composition of each structural unit of the polymer was confirmed to be substantially the same as the above-mentioned polymer A by measurement of 1 H-NMR spectrum) Was heated and kneaded at 280 ° C., extruded from a circular die having a diameter of 40 mm and a slit width of 0.6 mm, and a film having a thickness of about 100 μm was obtained by an inflation film forming method. The oxygen permeability of the film was measured using a gas permeability measuring device OX-TRAN10 / 50A manufactured by MODERN CONTROLOLS.
The measurement was performed under the conditions of ° C and 65% relative humidity. In addition, this film was produced using a biaxial stretching device manufactured by Toyo Seiki Seisaku-sho, Ltd.
As a result of simultaneous biaxial stretching of 3 × 3 times (9 times the area) at a temperature of 150 ° C., a film having a uniform thickness of about 10 μm was obtained.

The logarithmic viscosity of the polymer, the result of DSC analysis,
Table 1 shows the results of the evaluation of the oxygen permeability and the stretchability of the film.
And Table 2.

Further, using the above-mentioned film having a thickness of about 100 μm obtained by the above-mentioned inflation film forming method as an intermediate layer and a polypropylene sheet having a thickness of about 300 μm as an inner and outer layer, dry laminating is performed, and a three-layer multilayer sheet is formed. Obtained. As a dry laminating adhesive, two-pack type urethane adhesive Taketake A-385 (manufactured by Takeda Pharmaceutical Co., Ltd.) is used as a main agent, and Takenate A-10 (manufactured by Takeda Pharmaceutical Co., Ltd.) is used as a curing agent. }It was used. The amount of the adhesive applied was 4.0 g / m @ 2. After lamination, 40
Curing was carried out for 3 days. The thermoforming of the multilayer sheet was performed by using a vacuum press forming machine manufactured by Asano Laboratories Co., Ltd.
° C, the bottom has a radius of 33 mm and the top opening has a radius of 3
A cup-shaped container having a circular shape of 7 mm and a height of 37 mm was obtained.
The cup had good appearance without any uneven stretching such as cracks and uneven thickness.

The obtained cup was filled with corned beef as a content and replaced with nitrogen gas, and then heat-sealed as a lid with a laminated film of aluminum foil / polypropylene to obtain a sealed container to obtain a test sample (1). A 110 cc glass bottle was filled with corned beef, purged with nitrogen gas, and sealed with an aluminum cap to prepare a control sample (0). The above sample was subjected to a retort apparatus (Hisaka Manufacturing Co., Ltd., high temperature and high pressure cooking sterilization tester RCS).
-40 RTGN) and a retort treatment at 120 ° C. for 60 minutes was performed. After retort treatment, Sample (1) did not show any particular defect in appearance and morphology. This sample (1) was placed in a control sample (0) at 20 ° C. and 65% RH.
Was stored in a refrigerator (5 ° C.). Three months later, both were opened,
When age and gender were evaluated by 10 panelists randomly selected, 10 out of 10 panelists showed no change in taste, color and odor, and had good storage stability. Tables 1 and 2 also show the results of the thermoformability and the retort test.

Example 2 A polyester was obtained in the same manner as in Example 1 except that the molar ratio of polyethylene naphthalate / 6-acetoxy-2-naphthoic acid was changed to 50/50. This polymer was observed under a polarizing microscope crossed Nicols using the apparatus used in Example 1. Light transmission started at around 230 ° C., and the transmitted light amount further increased with increasing temperature,
Finally, even when the temperature was raised to 350 ° C., an optically anisotropic molten phase was still formed. Further, a sample obtained by rapidly cooling the polymer from a molten state was analyzed by DSC at a heating rate of 10 ° C./min. As a result, a glass transition point at 82 ° C. and a slightly endothermic peak at 235 ° C. were observed. Further, the crystallinity of a sample obtained by quenching the polymer from the molten state was measured by wide-angle X-ray scattering. As a result, the crystallinity was 11%. Next, injection molding was performed under the same conditions as in Example 1, and the bending strength and the bending elastic modulus were measured. The results shown below were obtained (in each case, the flow direction of the resin). Further, other evaluation tests were performed in the same manner as in Example 1.

Bending strength 2046 kg / cm
$ 2

Bending elastic modulus 12.1 × 10 ↑ 4
kg / cm ↑ 2

Tables 1 and 2 show the logarithmic viscosity of the obtained polymer, the results of DSC analysis, the oxygen permeability of the film, the stretchability, the thermoformability and the results of the retort test.

Example 3 A polyester was obtained in the same manner as in Example 1 except that the molar ratio of polyethylene naphthalate / 6-acetoxy-2-naphthoic acid was changed to 60/40. When the polymer was observed under a polarizing microscope crossed Nicols using the apparatus used in Example 1, light began to be transmitted from around 250 ° C., and thereafter, the amount of transmitted light increased further with an increase in temperature,
Finally, even when the temperature was raised to 350 ° C., an optically anisotropic molten phase was still formed. Further, as a result of analyzing a sample obtained by quenching the polymer from a molten state by a DSC at a heating rate of 10 ° C./min, a glass transition point was observed at 80 ° C. and an endothermic peak was observed at 252 ° C. Next, injection molding was performed under the same conditions as in Example 1, and the bending strength and the bending elastic modulus were measured. The results shown below were obtained (in each case, the flow direction of the resin). Further, other evaluation tests were performed in the same manner as in Example 1.

Bending strength 1844 kg / cm
$ 2

Bending elastic modulus 10.8 × 10 ↑ 4
kg / cm ↑ 2

The logarithmic viscosity of the obtained polymer, the result of DSC analysis, the amount of oxygen permeation of the film, the stretchability, the thermoformability and the result of the retort test are shown in Tables 1 and 2.

Example 4 A polyester was obtained in the same manner as in Example 1, except that the molar ratio of polyethylene naphthalate / 6-acetoxy-2-naphthoic acid was changed to 30/70. When the polymer was observed under a polarizing microscope crossed Nicols using the apparatus used in Example 1, light began to be transmitted from around 150 ° C., and the transmitted light amount further increased with increasing temperature,
Finally, even when the temperature was raised to 350 ° C., an optically anisotropic molten phase was still formed. In addition, as a result of analyzing a sample obtained by quenching the polymer from a molten state by a DSC at a heating rate of 10 ° C./min, no endothermic peak was observed except for the glass transition point at 93 ° C. Further, the crystallinity of a sample obtained by quenching the polymer from a molten state was measured by X-ray wide-angle scattering. As a result, the crystallinity was 7%. Further, other evaluation tests were performed in the same manner as in Example 1.

The logarithmic viscosity of the obtained polymer, the results of DSC analysis, the oxygen permeability of the film, the stretchability, the thermoformability and the results of the retort test are shown in Tables 1 and 2.

Example 5 1504 g (8.0 mol) of 6-hydroxy-2-naphthoic acid, 918 g (9.0 mol) of acetic anhydride, phenol /
Using a stirrer, 484 g (2.0 mol) of polyethylene naphthalate having an intrinsic viscosity of 0.65 dl / g measured at 30 ° C. using a mixed solvent of tetrachloroethane and the like, and 960 g (16.0 mol) of acetic acid as a reaction solvent. The reaction system was charged to a reactor having an internal volume of 8 liters equipped with a distillation column and a nitrogen gas injection port. After the inside of the reaction system was replaced with nitrogen three times, the mixture was stirred and heated under a nitrogen stream under reflux conditions for about 2 hours. Then, about 3
After the temperature was raised to 290 ° C. over a period of time, the pressure inside the system was gradually reduced, and the reaction was carried out at about 30 mmHg for about 2 hours. As a result, about 95% of the theoretical amount of acetic acid and acetic anhydride were distilled off. Next, the degree of vacuum in the reaction system was further increased, and the reaction was carried out at 1 mmHg or less for 1 hour, and then the produced polyester was taken out.

The polymer was observed under a polarizing microscope crossed Nicols using the apparatus used in Example 1.
Light began to be transmitted from the vicinity, and thereafter, the amount of transmitted light increased further as the temperature was increased. Even when the temperature was finally increased to 350 ° C., an optically anisotropic molten phase was still formed. Further, as a result of analyzing a sample obtained by quenching the polymer from the molten state at a heating rate of 10 ° C./min by DSC, no endothermic peak was observed at all except for a glass transition point at 97 ° C. Further, the crystallinity of a sample obtained by quenching the polymer from a molten state was measured by X-ray wide-angle scattering, and as a result, the crystallinity was 9%.
Met. Further, other evaluation tests were performed in the same manner as in Example 1.

The logarithmic viscosity of the obtained polymer, the results of DSC analysis, the oxygen permeability of the film, the stretchability, the thermoformability, and the results of the retort test are shown in Tables 1 and 2.

Example 6 In Example 5, 564 g (3.0 mol) of 6-hydroxy-2-naphthoic acid, 367 g (3.6 mol) of acetic anhydride and 360 g (6.0 mol) of acetic anhydride were used. Mol) and 1694 g of polyethylene naphthalate (7.
0 mol) to obtain a polyester in the same manner as in Example 5. When this polymer was observed under a polarizing microscope crossed Nicols using the apparatus used in Example 1, it was found that 250
The light began to be transmitted from around ℃, and thereafter, the amount of transmitted light increased further with an increase in the temperature, and the optically anisotropic molten phase was still formed even when the temperature was finally increased to 350 ℃. Also,
As a result of analyzing a sample obtained by quenching the polymer from a molten state by a DSC at a heating rate of 10 ° C./min, a glass transition point at 122 ° C. and an endothermic peak at 256 ° C. were observed. Further, other evaluation tests were performed in the same manner as in Example 1.

The logarithmic viscosity of the obtained polymer, the results of DSC analysis, the oxygen permeability of the film, the stretchability, the thermoformability and the results of the retort test are shown in Tables 1 and 2.

Example 7 In Example 5, 376 g (2.0 mol) of 6-hydroxy-2-naphthoic acid, 245 g (2.4 mol) of acetic anhydride, 240 g (4.0 mol) of acetic acid were used. Mol) and 1936 g of polyethylene naphthalate (8.
0 mol) to obtain a polyester in the same manner as in Example 5. When this polymer was observed under a polarizing microscope orthogonal Nicols using the apparatus used in Example 1, 255
The light began to be transmitted from around ℃, and thereafter, the amount of transmitted light increased further with an increase in the temperature, and the optically anisotropic molten phase was still formed even when the temperature was finally increased to 350 ℃. Also,
As a result of analyzing a sample obtained by quenching the polymer from a molten state by a DSC at a heating rate of 10 ° C./min, a glass transition point at 122 ° C. and an endothermic peak at 258 ° C. were observed. Further, other evaluation tests were performed in the same manner as in Example 1.

The logarithmic viscosity of the obtained polymer, the result of DSC analysis, the oxygen permeability of the film, the stretchability, the thermoformability, and the results of the retort test are shown in Tables 1 and 2.

Example 8 Polyethylene terephthalate (4.0 mol) having an intrinsic viscosity of 0.70 dl / g measured at 30 ° C. using a mixed solvent of phenol / tetrachloroethane and the like in place of polyethylene naphthalate in Example 1 And a polyester was obtained in the same manner as in Example 1 except that the polymerization temperature was changed to 280 ° C. When this polymer was observed under a polarizing microscope crossed Nicols using the apparatus used in Example 1, light began to be transmitted from around 180 ° C., and thereafter, the amount of transmitted light further increased with increasing temperature, and finally increased to 350 ° C. Even when the temperature was raised to the maximum, an optically anisotropic molten phase was still formed. In addition, a sample obtained by quenching the polymer from the molten state was taken as 1
As a result of DSC analysis at a heating rate of 0 ° C./min, no endothermic peak was observed except for the glass transition point at 82 ° C. Furthermore, as a result of measuring the crystallinity of a sample obtained by rapidly cooling the polymer from a molten state by X-ray wide-angle scattering,
The crystallinity was 13%. Further, other evaluation tests were performed in the same manner as in Example 1.

The logarithmic viscosity of the obtained polymer, the results of DSC analysis, the oxygen permeability of the film, the stretchability, the thermoformability, and the results of the retort test are shown in Tables 1 and 2.

Example 9 Example 3 was repeated, except that the same polyethylene terephthalate (6.0 mol) as used in Example 8 was used instead of polyethylene naphthalate, and the polymerization temperature was changed to 280 ° C. A polyester was obtained in the same manner as described above. When this polymer was observed under a polarizing microscope crossed Nicols using the apparatus used in Example 1, light began to be transmitted from around 225 ° C., and thereafter, the amount of transmitted light further increased with an increase in temperature. Even when the temperature was raised to the maximum, an optically anisotropic molten phase was still formed. A sample obtained by rapidly cooling the polymer from a molten state was analyzed by DSC at a heating rate of 10 ° C./min.
An endothermic peak was observed at ° C. Further, other evaluation tests were performed in the same manner as in Example 1.

The logarithmic viscosity of the obtained polymer, the results of DSC analysis, the oxygen permeability of the film, the stretchability, the thermoformability, and the results of the retort test are shown in Tables 1 and 2.

Example 10 In Example 5, 1128 g (6.0 mol) of 6-hydroxy-2-naphthoic acid, 643 g (6.3 mol) of acetic anhydride, 720 g (12.0 mol) of acetic acid were used as a raw material and a solvent. A polyester was obtained in the same manner as in Example 5 except that 484 g (2.0 mol) of polyethylene naphthalate and 384 g (2.0 mol) of the same kind of polyethylene terephthalate used in Example 8 were used. When this polymer was observed under a polarizing microscope crossed Nicols using the apparatus used in Example 1, light began to be transmitted from around 150 ° C., and thereafter, the amount of transmitted light increased further with an increase in temperature, and finally increased to 350 ° C. Even when the temperature was raised to the maximum, an optically anisotropic molten phase was still formed. Further, as a result of analyzing a sample obtained by quenching the polymer from a molten state by a DSC at a heating rate of 10 ° C./min, an endothermic peak was not observed at all except for a glass transition point at 85 ° C. Further, other evaluation tests were performed in the same manner as in Example 1.

The logarithmic viscosity of the obtained polymer, the result of DSC analysis, the oxygen permeability of the film, the stretchability, the thermoformability and the result of the retort test are shown in Tables 1 and 2.

Comparative Example 1 A polyester was obtained in the same manner as in Example 1 except that p-acetoxybenzoic acid (6.0 mol) was used instead of 6-acetoxy-2-naphthoic acid. The polymer was observed under a polarizing microscope crossed Nicols using the apparatus used in Example 1. When the polymer started to transmit light at around 255 ° C., the transmitted light amount further increased with increasing temperature,
Finally, even when the temperature was raised to 350 ° C., an optically anisotropic molten phase was still formed. Further, as a result of analyzing a sample obtained by quenching the polymer from the molten state by a DSC at a heating rate of 10 ° C./min, no glass transition point was observed, and only an endothermic peak was observed at 258 ° C. Furthermore, the crystallinity of a sample obtained by quenching the polymer from a molten state was measured by wide-angle X-ray scattering. As a result, the crystallinity was 27%. Also,
Other evaluation tests were performed in the same manner as in Example 1.

The logarithmic viscosity of the obtained polymer, the results of DSC analysis, the oxygen permeability of the film, the stretchability, the thermoformability, and the results of the retort test are shown in Tables 1 and 2.

Comparative Example 2 A polyester was obtained in the same manner as in Example 1 except that p-acetoxybenzoic acid (4.0 mol) was used instead of 6-acetoxy-2-naphthoic acid. When this polymer was observed under a polarizing microscope crossed Nicols using the apparatus used in Example 1, light began to transmit at around 260 ° C., and thereafter, the amount of transmitted light further increased with increasing temperature,
Finally, even when the temperature was raised to 350 ° C., an optically anisotropic molten phase was still formed. In addition, as a result of analyzing a sample obtained by rapidly cooling the present polymer from a molten state at a heating rate of 10 ° C./min by DSC, no glass transition point was observed, and only an endothermic peak was observed at 263 ° C. Further, other evaluation tests were performed in the same manner as in Example 1.

The logarithmic viscosity of the obtained polymer, the results of DSC analysis, the oxygen permeability of the film, the stretchability, the thermoformability and the results of the retort test are shown in Tables 1 and 2.

Comparative Example 3 A polyester was obtained in the same manner as in Example 1 except that p-acetoxybenzoic acid (6.0 mol) was used instead of 6-acetoxy-2-naphthoic acid. When this polymer was observed under a polarizing microscope crossed Nicols using the apparatus used in Example 1, light began to be transmitted from around 200 ° C., and thereafter, the amount of transmitted light further increased with increasing temperature,
Finally, even when the temperature was raised to 350 ° C., an optically anisotropic molten phase was still formed. In addition, as a result of analyzing a sample obtained by quenching the polymer from a molten state by a DSC at a heating rate of 10 ° C./min, no glass transition point was observed, and only an endothermic peak was observed at 205 ° C. Next, injection molding was performed under the same conditions as in Example 1, and the bending strength and the bending elastic modulus were measured. The results shown below were obtained (in each case, the flow direction of the resin). Further, other evaluation tests were performed in the same manner as in Example 1.

Bending strength 970 kg / cm ↑
2

Flexural modulus 8.1 × 10 ↑ 4k
g / cm ↑ 2

The logarithmic viscosity of the obtained polymer, the result of DSC analysis, the oxygen permeability of the film, the stretchability, the thermoformability and the result of the retort test are shown in Tables 1 and 2.

Comparative Example 4 A polyester was obtained in the same manner as in Example 1, except that the molar ratio of polyethylene naphthalate / 6-acetoxy-2-naphthoic acid was 90/10. This polymer was observed under a polarizing microscope crossed Nicols using the apparatus used in Example 1, and did not form an optically anisotropic molten phase at any temperature of 350 ° C. or lower. A sample obtained by quenching the polymer from a molten state was subjected to 10 ° C /
As a result of a DSC analysis at a heating rate of 1 minute, a glass transition point was observed at 123 ° C and an endothermic peak was observed at 260 ° C. Also,
Other evaluation tests were performed in the same manner as in Example 1.

The logarithmic viscosity of the obtained polymer, the result of DSC analysis, the oxygen permeability of the film, the stretchability, the thermoformability and the result of the retort test are shown in Tables 1 and 2.

Comparative Example 5 166 g (1.0 mol) of terephthalic acid, 100 g (0.52 mol) of resorcinol diacetate, and 104 g (0.5 mol) of methylhydroquinone diacetate
Was charged into a reactor equipped with a stirrer, a distillation column and a nitrogen gas inlet, and after the inside of the reaction system was replaced with nitrogen three times, the temperature was raised to 200 ° C. to 320 ° C. over 5 hours while stirring under a nitrogen stream, About 90% of the distilled acetic acid was distilled off. Thereafter, the degree of vacuum in the reaction system was further increased, and the reaction was carried out at 1 mmHg or less for 1 hour to take out the polymer.

The polymer was observed under a polarizing microscope crossed Nicols using the apparatus used in Example 1.
Light began to be transmitted from the vicinity, and thereafter, the amount of transmitted light increased further as the temperature was increased. Even when the temperature was finally increased to 350 ° C., an optically anisotropic molten phase was still formed. Further, a sample obtained by rapidly cooling the present polymer from a molten state was analyzed by DSC at a heating rate of 10 ° C./min. As a result, a glass transition point at 127 ° C. and an endothermic peak at 200 ° C. were observed. Further, the crystallinity of a sample obtained by quenching the polymer from the molten state was measured by X-ray wide-angle scattering. As a result, the crystallinity was 10%. Further, other evaluation tests were performed in the same manner as in Example 1.

The logarithmic viscosity of the obtained polymer, the results of DSC analysis, the oxygen permeability of the film, the stretchability, the thermoformability and the results of the retort test are shown in Tables 1 and 2.

Comparative Example 6 The results of DSC analysis of the polyethylene naphthalate used in Example 1 and the results of the oxygen permeability, stretchability, thermoformability and retort test of the film are shown in Tables 1 and 2.

Comparative Example 7 DSC of polyethylene terephthalate used in Example 6
Tables 1 and 2 also show the analysis results, the oxygen permeability of the film, the stretchability, the thermoformability, and the results of the retort test.

Examples 11 to 13 and Comparative Examples 8 to 9 Using the inflation films obtained in Examples 1 to 3 and Comparative Examples 6 and 7 at a temperature of 100 to 240 ° C.
The film was simultaneously biaxially stretched by a factor of 3 and heat-set at a temperature of 120 to 200 ° C. for 15 minutes to obtain a biaxially stretched film. Table 3 shows the oxygen permeation amount of the obtained film.

[0104]

[Table 1]

[0105]

[Table 2]

[0106]

[Table 3]

[0107]

The gas barrier property, thermoformability, hot water resistance and retort resistance are excellent.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-60-186526 (JP, A) JP-A-1-182319 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B32B 1/00-35/00 B65D 65/40 B65D 1/00-1/48 C08G 63/60

Claims (4)

(57) [Claims] 1. At least one resin mainly composed of a thermoplastic resin.
And species of the layers, substantially following formula 1 ## STR1 ## (In the formula 1, Ar represents a 1,4-phenylene group or a 2,6-naphthylene group.) A structural unit (1) represented by the following formula: The structural unit (2) represented by the following formula 3 Wherein the structural unit (1) and the structural unit (2) are contained in substantially equal moles, and the total amount of the structural unit (1) and the structural unit (2) is 15 to 90 mol%, the amount of the structural unit (3) is 10 to 85 mol% ,
And the oxygen permeation amount is 20 cc · 20 μm / m ² · day ·
A multilayer container comprising a laminate with a layer of a thermo-liquid crystalline polyester of atm or less . 2. A heat-stretched multilayer laminate.
The multilayer container according to claim 1, wherein 3. The multilayer container according to claim 1 or 2,
A package filled with contents. 4. The multilayer container according to claim 1 is filled with the contents, sealed, and then subjected to hot water or steam treatment .
And a method for producing a package .