JPS63296941A - Heat-resistant polyester container with gas barrier properties - Google Patents

Abstract

PURPOSE:To improve gas barrier properties and shock resistance drastically, to enable preservation of the contents for a long period of time and to enable grille and oven heating, by making use of a multi-layer vessel where it possesses a heat-resistant resin layer on one side of a specific ethylene-vinyl acetate copolymer saponified matter layer and an adhesive resin layer between them further and a shrinkage factor of a belly part of the vessel under specific heating conditions is at most a set value. CONSTITUTION:To make use of a heat-resistant multi-layer polyester vessel where it possesses a heat-resistant polyester PET layer at least on one face of an ethylene- vinyl acetate copolymer saponified matter EVOH layer, whose ethylene content is 25-60mol.%, a degree of saponification of an ingredient of vinyl acetate is 90mol.% or higher, preferably 96mol.% or higher, a thermoplastic polyester adhesive resin layer between the EVOH layer and PET layer, a shrinkage factor of a belly part of the vessel at 10% or lower at the time when it is heated for 30 minutes in an oven or a range at 220 deg.C and gas barrier properties. It is especially effective to add a crystallization accelerator to a polymer by making ethylene terephthalate into a main constituent unit of the PET.

Description

Detailed Description of the Invention Human and Industrial Application Fields The present invention is a multilayer polyester container that has high gas barrier properties and can be distributed at room temperature.
Contents (food), not food that can be stored for a long time
You can use it in boiling, microwave heating, and grill open heating (without transferring it to another container).
The present invention relates to a heat-resistant multilayer polyester container that has high gas barrier properties and can be used at temperatures up to 220°C.

B. Conventional technology A crystallization accelerator is added to thermoplastic polyester (PET) whose main repeating unit is ethylene terephthalate, and heat-setting is performed during thermoforming or in a subsequent process to achieve heat resistance (220°C). The method for imparting the following is known (Japanese Unexamined Patent Publication No. 59-62660), and a large number of heat-resistant containers have been manufactured. The heat-resistant PET container contains contents (food)
Boil heating, microwave heating, and open grill heating are possible without transferring to another container.

In particular, the ability to heat the grill open makes it possible to add nibbles to the surface of the food. Therefore, it was expected that the uses of such containers would further expand, but at present they are only used for limited purposes due to the following problems. That is, the container is made of PET to provide heat resistance.
It is necessary to increase the crystallinity of As a result, the impact strength is reduced, and although some containers are made of laminated thin PET layers, they do not have sufficient strength. Even more tragically, when the thickness of the container was increased to make it more reusable, there was a major problem in that the impact resistance decreased, making the container more susceptible to breakage. Furthermore, since the gas barrier properties of the container are poor, if food is to be stored in this container for a long period of time, it must be stored at a low temperature (frozen or refrigerated). Therefore, to make matters worse, PET containers with increased crystallinity exhibit even lower impact strength at low temperatures, making the containers more likely to break.

Therefore, as a method to improve these drawbacks and to significantly improve the long-term storage stability of foods at room temperature, a method of combining other functional resins, such as gas barrier resins, with the PET layer may be considered. Therefore, the PET layer should be made of polyvinylidene chloride (PVDC) or polyacrylonitrile (P).
A heat-resistant multi-layer PET container with gas barrier properties was created by combining AN), but grill open heating (220
℃), the coloring and odor were so severe that it was unusable.

On the other hand, saponified ethylene-vinyl acetate copolymer (EVO) I), which has the best gas barrier properties, has almost no coloration or odor when heated with an open grill (220°C). It is considered to be an effective resin that solves the problem. However, as an adhesive resin for bonding the PET layer and the EVOH layer, polyolefins or ethylene-vinyl acetate copolymers to which ethylenically unsaturated carboxylic acid or its acid anhydride (e.g., maleic anhydride) is added or grafted are used. , ethylene-acrylic acid copolymer, ethylene-acrylic acid copolymer, metal salts thereof, etc., when grill open heating (220°C),
Not only was the adhesive resin colored and had a strong odor, but also peeling occurred at the interface of the adhesive layer, probably due to insufficient adhesiveness, making it unusable.

Problems that C9 Ming is trying to resolve EVOH/PET composite containers are a container that has excellent gas barrier properties without impairing the performance of PET containers, which have good heat resistance. This container is 1. In addition to having high gas barrier properties, it not only allows distribution at room temperature and long-term storage, but also allows the contents (food) to be stored in the same container without being transferred to another container. It is an excellent container that can be heated by boiling, microwave heating, and open grill heating (220°C or less).

However, there is almost no adhesive resin to effectively bond the PET M and EVOH layers, and even if there was, the adhesive resin would be discolored and emit a strong odor when heated with an open grill (220°C). However, due to insufficient adhesion, peeling occurred at the interface of the adhesive layer, and the product was not usable at all.

Therefore, the present inventors conducted a thorough study on heat-resistant polyester containers having a PET layer and an EV OH layer, and found that when heated with an open grill (220°C), the blue color and odor of the adhesive resin Not only was there almost no peeling at the interface of the adhesive layer, but surprisingly, the container was less likely to break, probably due to the increased impact strength of the container, and as a result, the thickness of the container was increased. They discovered the possibility of making a rigid container and completed the present invention.

Means for Solving Points D and Il The present invention has an ethylene content of 25 to 60 mol% and a saponification degree of vinyl acetate component of 90 mol% or more, preferably 96 mol%.
Having a #thermal polyester (B) layer on at least one side of the saponified ethylene-vinyl acetate copolymer (4) layer,
Container body (longitudinal direction) when thermoplastic Borienether-based adhesive resin (C) WIJ is provided between the circuit layer and the (B) layer, and heated in an oven at 220°C for 30 minutes.
This is a heat-resistant multilayer polyester container with gas barrier properties and a shrinkage rate of 10% or less.

Detailed explanation of E1 invention The present invention will be explained in more detail below.

The PET used in the present invention is a polyester containing ethylene terephthalate as a main unit, 80 mol% or more, preferably 90 mol% or more of ethylene terephthalate units, dicarboxylic acids other than terephthalic acid, or It can contain glycol components other than ethylene glycol. Note that dicarboxylic acids other than terephthalic acid include aromatic dicarboxylic acids such as isophthalic acid, orthophthalic acid, naphthalene dicarboxylic acid, diphenyl ether dicarboxylic acid, diphenyl-4,4 dicarboxylic acid, oxalic acid, malonic acid,
These include aliphatic dicarboxylic acids such as succinic acid, geltanic acid, adipic acid, pimelic acid, corkic acid, azelaic acid, and heptapasic acid, and alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid. Glycol components other than ethylene glycol that can be used include ], 3-propanediol, ], 4-butanediol, 1,5-bentanediol, 1,6-hexanediol, and 9-nonanediol. ,
Examples include aliphatic glycols such as diethylene glycol and triethylene glycol, and alicyclic diols such as cyclohexanediol and cyclohexane dimetatool, and one or more of these can be used. The molecular weight of the polyester greatly affects sheet molding or the physical properties of containers, so the intrinsic viscosity is 0.60.
It is desirable that it be at least a/9, preferably at least 0.70 a/f. The intrinsic viscosity here is a value measured at 30° C. in a mixed solvent of phenol/tetrachloroethane (1:1 weight ratio).

Furthermore, in order to increase the crystallization rate of the polyester, which is practically important in molding heat-resistant containers, a method of adding a crystallization accelerator to the polymer is particularly effectively utilized in the present invention. Here, the crystallization accelerator can be selected from a wide variety of compounds, and one group of them includes inorganic compounds having a minute particle size (2 to 3 μm or less). Examples include talc, silica, calcium carbonate, titanium dioxide, and magnesium oxide.

These are generally used in a proportion of 0.01 to 5% by weight based on the PET. Another group includes polyolefins, especially polymers made from olefin monomers having 2 to 6 carbon atoms, such as low density polyethylene, high density polyethylene, flocculent low density polyethylene, polypropylene, polyisopropylene, polybutene , poly-4-methylpentene, and the like. These are used in a proportion of 1 to 15% by weight, more preferably 2 to 8% by weight, based on the PET. Furthermore, 7 to 30
Examples include sodium stearate, sodium benzoate, and potassium salts of organic acids having 5 carbon atoms, potassium salts, or sodium salts of organic polymers having carboxyl groups.
Mention may be made of the sodium salts (such as ionomers) of ethylene-acrylic acid or methacrylic acid copolymers, the sodium salts (fully or partially neutralized salts) of styrene-maleic anhydride copolymers. The amount of these added to the PET is generally 0.01 to 5 M% by weight for organic acid salts and 0.1 to 10% by weight for salts of organic polymers.

Furthermore, since the final product is exposed to high temperatures for a long period of time, it is effective to add 0.05 to 5% by weight of a heat stabilizer to PET. Furthermore, one or more of the following heat stabilizers are often added. Examples of heat stabilizers include alkylated substituted phenols, bisphenols, substituted bisphenols, thiobisphenols, polyphenols, thiobisacrylates, aromatic amines,
Examples of aromatic amines include primary polyamines, diallylamine, bis-diallylamine, alkylated diallylamine, ketone-diallylamine condensation products, aldehyde-amine condensation products, and aldehyde-amines. can be opened. In addition, as a highly preferable heat stabilizer, 2
There are polyphenols having a phenol ring structure of more than
-di(-butyl-4-hydroxydiphenyl)-hyropionate)methane and 1,3.5-)limethyl-2
．． Examples include 4.6-tris(3.5-di-t-butyl-4-hydroxybenzyl)benzene. Among them, tetrakis(methylene 3-(3.5-di also monobutyl-4-hydroxydiphenyl)methane) is particularly preferably used.In addition, when mixing these, other additives (plasticizers, lubricants, antistatic Agents, especially coloring agents, etc.) may be used freely within the range that does not impede the effects of the present invention.Furthermore, the foamed structure or the frame structure may be resistant to heat, ultraviolet rays, or electron beams. In order to
It is possible to add an otogenerating agent, a crosslinking agent, and an auxiliary agent depending on the purpose.

Uniformly dispersing crystallization accelerators, heat stabilizers, and other additives in the PET beyond the margins below is important because it has a significant impact on the performance of the final product container, but its addition and uniform dispersion is important. There are no particular limitations on the method of
A method of adding additives such as the crystallization accelerator during the polymerization of PET, a method of tri-blending additives to PET, melt extrusion, and blending PET in a desired ratio to a master pellet made into a pellet, a method of adding additives to PET. Direct use of triblended, melt extruded and pelletized resin;
Examples include a method in which additives are blended with PET and used directly. Suitable methods include a method of adding the additive during polymerization of PET, or a method of triblending the additive with PET, melt extruding it, and directly using a pelletized resin. The obtained PET composition has an intrinsic viscosity of 0.65 to 1.2 when measured in a pheno-/I//tetofchloroethane mixed solvent (1:1 weight ratio) at 30°C;
Preferably, the intrinsic viscosity is increased to 0.70 to 1.0, depending on the case, by a commonly used solid phase polymerization method or the like.

The EVOH used in the present invention has an ethylene content of 20 to
60 molv! %, preferably 25-55-T:A/%,
The degree of saponification of the vinyl acetate component is 9096 or higher, preferably
It is a saponified ethylene-vinyl acetate copolymer of 961N or more. When the ethylene content becomes 20 molv96 or less,
The molding temperature becomes close to the decomposition temperature, making molding difficult. On the other hand, if the ethylene content is 60 mol% or more, the gas barrier properties will deteriorate, which is not preferable. In addition, the degree of saponification of the vinyl acetate component is less than 96%, especially less than 9096 12VOH
is undesirable because gel-like substances tend to occur frequently and gas barrier properties are low. Furthermore, EVOH with has a silicon compound in the molecule and 0. It is more desirable to contain 0005 to 0.2 mo/L/96. When using such EVOH containing silicon compounds, the EVOH in a multilayer container
Under moisture absorption layer, empty state without food in particular, 220
℃ When heated in the oven for 30 minutes, EVOH f
This is preferable because it improves the interlayer adhesion between f and the adhesive resin layer. Further, it may be preferable to use the silicon compound-containing EVOH by mixing the silicon compound-containing EVOH with an EVOH that does not contain a silicon compound. and,
The silicon unit contained in EVOH is as follows (Il, <1
Selected from 0 and side.

[However, here, n is O~1, m is 0~2, R1 is lower grade 7
- A lower alkyl group having a μ group, an allyl group, or an allyl group, R2 is an alkoxyl group having 1 to 40 carbon atoms, and the alkoxyl group may have an oxygen-containing substituent. R3 is hydrogen or a methyl group, R4 is hydrogen or a lower alkyl group, R' is an alkylene group or 2 in which chain carbon atoms are bonded to each other by oxygen or nitrogen.
a valent organic residue, R6 is hydrogen, halogen, a lower alkyl group, an allyl group, or a lower alkyl group having an allyl group,
R7 is an acyloxyl group or an acyloxyl group (here, the acyloxyl group or acyloxyl group may have a substituent having oxygen or nitrogen), Ha is hydrogen,
A halogen, a lower alkyl group, an allyl group, or a lower alkyl group having an allyl group, R9 is a lower alkyl group. More specifically, R1 represents a lower alkyl group having 1 to 5 carbon atoms, an allyl group having 6 to 18 carbon atoms, or a lower alkyl group having 1 to 5 carbon atoms having an allyl group having 6 to 18 carbon atoms. , R4 represents a hydrogen atom or a lower alkyl group of #1 to #5, and R8 represents a 7μ kylene group having 1 to 5 carbon atoms or a divalent organic residue in which chain carbon atoms are bonded to each other by oxygen or nitrogen. and R6 is hydrogen, halogen, a lower alkyl group having 1 to 5 carbon atoms, an allyl group having 6 to 18 carbon atoms, or 1 having an allyl group having 6 to 18 carbon atoms.
~5 lower alkyl group, R7 is an acyloxyl group having 1 to 40 carbon atoms or an acyloxyl group (here, a/v
:2KV/L/ group or acyloxyl group refers to a substituent having oxygen or nitrogen, a lower alkyl group having 1 to 5 carbon atoms, and a carbon number .

18 allyl group, or a lower 7y group having 1 to 5 carbon atoms, and R9 represents a lower alkyl group having 1 to 5 carbon atoms. Vinyltriethoxysilane, vinyltriethoxysilane, etc. are preferably used. The EVOH is ASTM-01238
-65T, the melt viscosity index measured at 190°C and 21601 load is 0.1 to 259710 minutes, preferably 0.
．． 3 to 20y/10 minutes. Further, one or more additives (various resins, antioxidants, plasticizers, colorants, etc.) may be freely used within the range that does not impede the effects of the present invention. In particular, as a measure to improve the thermal stability of EVOH and prevent gel formation, it is preferable to add a hindered phenol ρ type or hindered amine type thermal stabilizer in an amount of 0.0 to 5 weight.

As one typical example of the thermoplastic resin used in the present invention, the molar ratio of ester μ group/amide group is 90/10 to
10/900 polyester-amide copolymer. As the force μ ponic acid component of the copolymer, terephthalate μ
Aromatic dicarboxylic acids such as orthophthalic acid, naphthalene dicarboxylic acid, diphenyl ether dicarboxylic acid, diphenyl/L'-4.4 dicarboxylic acid, oxalic acid, malonic acid, succinic acid, geltanic acid, adipic acid, pimelic acid , aliphatic dicarboxylic acids such as corkic acid, azelaic acid, and sebacic acid, and alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid, and one or more of these can be used. In addition, the glyco-μ components include ethylene glycol, It 3-propanedio-A/, 1.4-butanediol, 1.5-pentanedio-μ, 1.6-hexanedio-μ, 9-nonanediol, diethylene glycol, Triethylene glycol ~,
aliphatic glycols and cyclohexanediol, such as
Examples include alicyclic di-y such as cyclohexane dimetatool, and one or more of these can be used. In addition, trivalent or higher-valent carboxylic acids or alcohols can also be used in small amounts. Furthermore, the amine components include piperazine, pentaethylene diamine, hexaethylene diamine, nonane ethylene diamine, deca ethylene diamine, undeca ethylene One or more acid amides such as mido, ω-amine hebutanoic acid, ω-aminononanoic acid, etc. can be used. A polyester-amide copolymer obtained by co-condensing these, a melt mixture composition of the copolymer and polyester or polyamide, and a mixture composition of polyamide and polyester are used.

When the ester/V group in these polyesteramides (in the case of a mixed composition, the composition) is 90 mol% or more, or when the amide group is 9O-e-/l/96 or more, the heat resistance Adhesion between PET and EVOH is not sufficient. The molar ratio of ester group/amide group is 85/15 to 15
/85 is more suitable. Preferably, the dicarboxylic acid component is one or more of terephthalic acid, adipic acid, azefinic acid, and succinic acid, and the glycol component is one or more of ethylene glycol and 1,4-cyclohexane dimetatool, and the amine component is preferably one or more of terephthalic acid, adipic acid, azefinic acid, and succinic acid. A polyester-amide containing biverazine and having an ester group/amide group molar ratio of 0/30 to 10/90, or one or more of terephthalic acid, adipic acid, azelaic acid and succinic acid as a dicarboxylic acid component, and 6 nylon, 6-66 nylon, 66 nylon, 6-12 nylon, 6-9 nylon, 10 to 80 weight of polyester containing one or more of ethylene glycol and 1,4-cyclohexane dimetatool as a glycol component. % solution polymerized compositions.

As a more preferable example of the thermoplastic polyester system used in the present invention, Kl and Cr are contained in a polyester composed of a dicarboxylic acid component and a glycol component.

One or more elements selected from the group consisting of Sn, Go, and Si in an amount of 0.1 to 100 moles of the dicarboxylic acid component.
Examples include modified polyesters containing 5 moles. As the metal element, among these, AI and Cr are preferable because they provide a large adhesive force, and M is particularly preferable. In addition, a phenomenon occurs in which the content is not less than 0.1 mole. In the present invention, these elements include embodiments in which these elements are mixed in polyester as compounds containing these elements, and further embodiments in which these elements are present in a state of being chemically bonded to polyester molecules, but the latter is preferable because high adhesive strength can be obtained. As a method for bonding the above-mentioned elements to polyester, a method of adding a compound of the above-mentioned element (particularly preferably a metal ester, a chelate compound, an organic acid salt, etc.) during polymerization of polyester can be mentioned.

For example, examples of the Al compound include aluminum acetylacetonate, aluminum ethoxide, aluminum propoxide, and reaction products of these compounds and monocarboxylic acids. Examples of the Cr compound include chromium acetylacetonate or chromium monocarboxylate, and examples of the Sn compound include tetofethyl stanate, tetofuprovir nutanate, tetofuptylstanate, or the reaction product of these with monocarboxylic acid. As the Ge compound, germanium dioxide is used, and as the Si compound, methyltriethoxysilane,
Methyltriethoxysilane, dimethyldimethoxysilane, and dimethyldimethoxysilane can be used. In particular, aluminum acetylacetonate,
Aluminum ethoxide and aluminum propoxide can be produced.

It is preferable to add these compounds to the polyester polymerization reaction system after the polyester polymerization reaction is almost completed and at 230° C. or lower.

The additive can be added by dissolving it in a diol, or by dissolving it in a monocarboxylic acid or its ester to prevent gelation of the polymer during polymerization. The dicarboxylic acid component constituting the thermoplastic polyester containing these elements includes aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, orthophthalic acid, naphthalene dicarboxylic acid, diphenyl ether dicarboxylic acid, and diphenyl-4,4 dicarboxylic acid. acid, aliphatic dicarboxylic acids such as oxalic acid, malonic acid, succinic acid, geltanic acid, adipic acid, pimelic acid, corkic acid, azelaic acid, sepacic acid, and alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid, One or more of these can be used.

In addition, glycol components include ethylene glycol, 1
．． 3-70 lovandiol, 1,4-butanediol,
Aliphatic glycols such as 1,5-bentanediol, 1,6-hexanediol, 1,9-nonanediol, diethylene glycol, triethylene glycol, and alicyclic diols such as cyclohexanediol and cyclohexane dimetatool are used. , one or more of these can be used. Furthermore, trivalent or higher carboxylic acids or alcohols can also be used in small amounts.

Preferably, the dicarboxylic acids used are terephthalic acid, isophthalic acid, and adipic acid, and the diols used are TEHA, ethylene glycol, and diethylene glycol.

The intrinsic viscosity of the obtained thermoplastic polyester is 0.50
dll/I or more, preferably 0.6
It is preferable that the value is 0/fI or more. The intrinsic viscosity here refers to the value measured at 30°C in a mixed solvent of phenol/tetrachloroethane (1:1 weight ratio). Extrusion lamination method, dofuifumi method, coextrusion lamination method, coextrusion sheet production method (
feedblock method, multi-manifold method, etc.)
There is a method of obtaining a multilayer sheet or parison by a coextrusion direct blow method, a coextrusion pipe method, a coinjection method, various solution coating methods, etc., and using these to obtain a container, or a method of directly obtaining a molded container. If the shaped container is obtained directly, the container is heat treated in a mold heated to a temperature sufficient to achieve the desired degree of crystallinity and impart heat resistance. The temperature range of the mold is 150 to 215°C,
The temperature is preferably 160 to 200°C and held in the mold for 2 to 60 seconds, preferably 2 to 20 seconds. On the other hand, it is important to rapidly cool the container immediately after obtaining the container from the multilayer sheet or parison by secondary processing. It is desirable that the multilayer sheet or parison (hereinafter referred to as multilayer structure) be externally heated and thermoformed as quickly as possible, and the thermoforming temperature range is 110°C.
-170°C, preferably 120-160°C. Also,
When thermoforming, E, which is a component of the multi-I structure,
The water content of VOHJ- is not particularly limited, but it is preferably within 0.01 to 5%. The thermoformed container is then heat treated in a mold heated to 1 ML degree, sufficient to achieve the desired degree of crystallinity and impart heat resistance. The temperature range of the mold is 150-215℃
The temperature is preferably 160 to 200°C, and the temperature is kept in the mold for 2 to 60 seconds, preferably 2 to 20 seconds. The molded product is hot and flexible, so care must be taken when removing it from the mold.In some cases, it may be necessary to put it back into a low-temperature mold or blow cold air into the mold to stop the molding. The shape of the item is adjusted. The molded product was heated in a microwave oven at 220℃ for 3
The shrinkage rate of the container body (vertical direction) when heated for 0 minutes is 10
% or less, preferably 6% or less. Here, the shrinkage rate of the container body (vertical direction) is 100 x (dimension before heating - 7
The value is calculated by dividing the dimension of Xl heat eroding by the dimension before heating.

There are no particular limitations on the shape of the multilayer structure, and it may be shaped like a tray, a cup, or a bolt. And regarding the stretching magnification when secondary processing the multi-layer m-adic body to make a molded container.

The area ratio is 20 or less, preferably 3 to 15 times.

Scraps generated by trimming when obtaining molded products are
After being pulverized, either directly or pelletized, it is recovered and used. The collection method is not particularly limited, but the scrap is crushed, and if it has absorbed moisture, it is dried and then tri-blended with raw PET, or the crushed scrap is pelletized and then tri-blended with raw PET. There is a method of blending, a method of blending pulverized scrap and raw material PET into pellets, etc. The blending ratio of the raw PET composition and scrap is usually about 2 to 100%. At this time, in order to improve dispersibility and thermal stability and suppress abnormalities during container molding, metal soaps (aliphatic or/or aromatic carboxylates, etc.), chelate compounds (EDTA, etc.), and alkalis or alkaline soil metal carbon cfj
! It may be preferred to add one or more salts.

Also, multi-layer hi! As for the construction process, PET composition/
EVOII / PETm composition, PEr composition / shielding property (
Support) fat/EVOH/contact resin/pzrm compound, P
ET composition/adhesive resin/EVOH/adhesive resin/PET composition/PET, PETM composition/adhesive resin/EVOH/adhesive resin/PET, PET/PE
T composition/adhesive tree j+y/avou/adhesive resin/PET composition/PET, PET composition/recovered PE
Tm compound/adhesive resin/EVOH/adhesive resin/PE
T composition, PET composition/recovered PET composition/adhesive resin/EVOH/adhesive resin/recovered PET composition/PE
T composition, PET composition/recovered PET composition/adhesive resin/resin/EVOH/adhesive resin/PET composition/PET
, PET/PET composition/Recovered PET Mi composition/
Representative examples include adhesive resin/EVOH/adhesive resin/PET compositions. The thickness of each layer is not particularly limited, but generally the total thickness of the container body is 200μ to 2000μ, the EVOH layer is 2tt to 200μ, and the adhesive resin layer is 2tt to 200μ.
It is μ~200μ.

The thus obtained multilayer container of the present invention has extremely good gas barrier properties and is also a food packaging container with good heat resistance. It is a container with excellent properties that allows it to be heated in a boiling oven, in a microwave oven, and even in a grill oven (220°C) without being transferred to another container. This container is also effective in fields where aromatic properties are required.

The present invention will be further explained below with reference to Examples.

The present invention is not limited in any way by this.

Example U - Example 1 EVOH had an ethylene content of 44 mol%, a degree of saponification of 99.4, a vinyl trimethoxyb of 70.02 mol%, and a melt index (Mii 190°C-2160y).
) 1.69/1 o min, and as a heat-resistant PET composition, MI (190
-2160, p) 3 parts by weight of low density polyethylene of 5.0 f710 minutes, 1.2 parts by weight of T'i 0x as a pigment, and 0.5 iffi part of Irganox 1010 (manufactured by Ciba Geigi) as a heat stabilizer were tri-blended. The pellets were pelletized using a twin screw type, vent type 40φ extruder and dried at 150° C. for 8 hours.

Further, as the adhesive resin, polyester/l/ obtained by the following method was used. That is, 0.20 mol of hexylene glycol 2004% aluminum inpropoxide and 0.20 mol of caprylic acid were placed in a 300 ml three-necked flask, which was equipped with a nitrogen gas introduction pipe, a stirrer, and a cooling pipe. lOmotv, 0.30 mol of P-oxybenzoic acid, and 0.20 mol of acetylacetone) were added and reacted at 100'C, resulting in an aluminum compound. Reterephthalate 64 p,
Adipic acid 36.57, ethylene glyco-tvx5.
59, add 14.99% diethylene glycol and 200℃
- To the solution reacted for 4 hours, tributyl phosphate/l/25μ
12 Antimony trioxide (40 ml) and the above aluminum compound were combined with 10 dicarboxylic acid components in terms of aluminum atoms.
After adding 0.52 mol to 07μ, the resin was heated to 260°C and polymerized for 90 minutes under reduced pressure at 275°C (1,1 mmHg).The intrinsic viscosity of this resin was 0. .61 dl/g, and the glass transition temperature was -5°C.

Using these resins, a sheet was produced using a feed block type 3 type 5 layer co-extrusion device.The thickness of the sheet was 800 μm of PET composition on the outer layer, and an adhesive resin layer on the inside. 50μ, and the EV OH layer in the middle layer is 50μ. The obtained sheet was thermoformed in a vacuum-pressure forming machine at a sheet temperature of 130°C and a drawing ratio of 1 in a round cup-shaped mold, and heat-fixed for 10 seconds at a mold temperature of 180°C. The appearance of the obtained container was good, and the shrinkage rate of the container when heated in a 220° C. oven for 30 minutes was 3%. However, the shrinkage rate of the container is a value calculated by lOOX (dimension before heating - dimension after heating)/dimension before heating in the body of the container (in the vertical direction). Moreover, the appearance of the container after heating was also good. On the other hand, when the gas barrier properties of the EVOH layer of this container were measured at 20°C and 65% RH using a model 10150 made by Mocon, the container before heating showed 1.8 CC, 20 μ/I, 24 hr, aim. 1.7 cc, 20 tt/rd in the latter container.

24hr mouth 1m and both have very good gas barrier!
! ,showed that.

By the way, fill the container with salad oil before heating.

The container was covered with a top lid (heat-sealed/L/) using a commercially available 10(lμ) biaxially oriented PET film laminated with a sealant. ) was measured.As a result,
The height of a fall that breaks 5 out of 10 containers is 1.5 m.
The above results showed good drop impact resistance. Also -20℃
It was 1m.

Example 2 In Example 1, EVOH was modified to have an ethylene content of 44 mo/
l/%, saponification degree 99.4%, M! (190℃-216
0p) Change to 1.6y/10min OIVOH and do 5! as in Example 1! provided. When the obtained container was heated in an oven at 220°C for 30 minutes, the shrinkage rate of the container showed almost the same value as in Example 16.Also, slight delamination was observed in the flange part of the container, but it was not used. , there were no problems.

Example 3 In Example 1, EVOH was mixed with ethylene content of 32 mol%, saponification degree of 99.4%, vinyltrimethoxysilane 0603 mol%% MI (190°C-21609) x,
6 g/lo min (7) The same procedure as in Example 1 was carried out except that the EVOH was changed and the sheet thickness and the intermediate EVOH layer were increased to 20 μm. The resulting container is good and has 2
The shrinkage rate of the container when heated in an oven at 20℃ is 4%.
The appearance of the container after heating was also good. The gas barrier properties of the EVOH layer of the heated container at 20°C and 65% RH were measured and found to be 0.6 CC, 20
It showed very good gas barrier properties with μ/rye, 24 hr, and atm. In addition, the containers filled with salad oil were dropped onto a concrete floor at 20°C and the impact resistance (drop height) was measured. As a result, the drop height at which 5 out of 10 containers were damaged was It was 1.5m or more.

Example 4 The same procedure as in Example 1 was repeated except that the low density polyethylene used as the crystallization accelerator was replaced with polypropylene. The resulting container was in good condition, with a shrinkage rate of 4% when heated in an oven at 220° C., and the appearance of the container after heating was also good. Then, the EVOI of the container after heating (gas barrier properties of the layer at 20°C and 65% RH was measured: 1.6cc, 20 it/rr
t, 24hr, aim, showing very good gas barrier properties.

Example 5 The same procedure as in Example 1 was carried out except that the addition rate of the crystallization accelerator was increased from 3% by weight to 6% by weight. The obtained container was in good condition, and the shrinkage rate of the container when heated in an oven at 220° C. was 4%, and the appearance of the container after heating was also good. And 20% of the EVOH layer of the container after heating.
When gas barrier properties were measured at ℃-65%RH, 1.
It showed very good gas barrier properties of 7 cc, 20 p/d, 24 hr, atm.

Example 6 In Example 1, the adhesive resin was azelaic acid/cyclohexanedimethanol/piperazine (molar ratio 0.501).
Intrinsic viscosity υ consisting of 0.0910.41), 75dt
! , /f (molar ratio of ester groups/amide groups 18/82) was carried out in the same manner as in Example 1. The resulting container was in good condition and had a good shrinkage rate of 4% when heated in an oven at 220°C. Although some coloring was observed in the appearance of the container after heating, it was not enough to cause a problem in use. Example 1
When the drop impact strength was measured in the same manner as above, the drop height at which 5 out of 10 containers were damaged was 1.5 m or more.

Example 7 In Example 1, the adhesive resin had an intrinsic viscosity of 0.75a/
100 parts by weight of modified polyethylene terephthalate containing 35 mol% of isophthalic acid No. 9 was mixed with 80 parts by weight of 6-66 nylon, and pelletized using a vent type 40φ extruder with a twin screw tie 7' to form a pellet at 150°C. 8
The same procedure as in Example 1 was carried out except that the resin was dried for a while. The molar ratio of ester groups/amide groups in this mixed pellet is 6.
It is 0/40. The resulting container is in good condition and at 220°C
The shrinkage rate of the container when heated in an oven was 3.5%, which was good.

The appearance of the '6 cup after heating also showed some discoloration, but it was not enough to cause any problems in use.

Comparative Example 1 The same procedure as in Example 1 was carried out without using EVOH. Although the obtained container was in good condition, the drop impact strength (drop height) when the container was dropped onto a concrete floor at 20° C. was 0.5 m or less. Furthermore, when the gas barrier property of the PET layer of the container was measured at 20°C and 65% RH, it was 97cc.

It has poor gas barrier properties of 20 μ/7 d and 24 hr, and cannot be used as a container for long-term food storage at room temperature.

Comparative example 2 5! The same procedure as in Example 1 was carried out except that the %r# thermal PET in Example 1 was replaced with ordinary PET. The obtained container was in good condition, but when the container was heated in a microwave oven at 220° C. for 30 minutes, the shrinkage rate of the container was 65%, which made it unusable.

Comparative Example 3 The same procedure as in Example 1 was carried out except that the adhesive resin was replaced with a maleic anhydride-modified ethylene-vinyl acetate copolymer. Place the resulting container in a microwave oven at 220°C for 3 days.
When heated for 0 minutes, the flange of the container peeled off, and to make matters worse, the odor was so strong that it became unusable.

G. Effects of the Invention The multilayer polyester container of the present invention is a heat-resistant multilayer polyester container with significantly improved gas barrier properties and 1##7 impact resistance, and the contents (food) can be stored at room temperature for a long period of time. Not only that, but it can also be heated by boiling, microwave heating, and grill open heating (with the contents (food) still in it).
220°C) is possible.

Claims (5)

[Claims] (1) A heat-resistant polyester resin (B) layer on at least one side of the saponified ethylene-vinyl acetate copolymer (A) layer with an ethylene content of 25 to 60 mol% and a saponification degree of vinyl acetate component of 90 mol% or more, Furthermore, it has a thermoplastic polyester adhesive resin (C) layer between the (A) layer and the (B) layer, and the container body (vertical direction) when heated in a microwave oven at 220°C for 30 minutes. The shrinkage rate is 10% or less,
Heat-resistant multilayer polyester container with gas barrier properties. (2) The multilayer polyester container according to claim 1, wherein the saponified ethylene-vinyl acetate copolymer (A) has a silicon content of 0.0005 to 0.2 mol%. (3) The multilayer polyester container according to claim 1, wherein the heat-resistant polyester resin (B) is a composition in which a crystallization accelerator is blended with a thermoplastic polyester containing 80 mol% or more of ethylene terephthalate units. (4) The adhesive resin layer (C) is a polyester-amide adhesive resin having an ester group/amide group ratio (molar ratio) of 90/10 to 10/90.
The multilayer polyester container described in Section 1. (5) The adhesive resin layer (C) is made of Al, Cr, Sn, Ge
A thermoplastic polyester containing 0.1 to 5 moles of one or more elements selected from the group consisting of The multilayer polyester container according to claim 1, which is a plastic polyester.