JPH0543584B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention is a novel heat-resistant and
This invention relates to a gas barrier multilayer container. (Prior art) Linear polyester in general, and polyethylene terephthalate (hereinafter referred to as PET) in particular, has attracted attention as a material for various containers including bottles due to its excellent mechanical and chemical properties. Demand is growing as a new transparent container material to replace polyolefin containers such as polyethylene and polyvinyl chloride, which have dominated the mainstream of containers. However, improvements in packaging technology and expansion of packaging applications require the addition of even higher functionality to PET containers.In particular, when considering alternative uses for metal cans and glass containers, it is important to use plastics to reduce weight. Although it has many advantages such as transparency and safety, its lack of performance in terms of gas barrier properties and heat resistance is a hindrance, greatly limiting its application. As a means of improving the gas barrier properties and heat resistance of such PET containers, bottles are known in which PET is laminated with a heat-resistant resin composition (hereinafter referred to as modified PAR) consisting of an oxygen barrier resin, an aromatic polyester, and PET. (Japanese Unexamined Patent Publication No. 59-214047). Common gas barrier resins include ethylene vinyl alcohol copolymer, polyvinylidene chloride, and polyacrylonitrile resins, and the development of composite technology for these resins and PET is actively underway. However, technical problems in terms of adhesion and processability have not yet been completely resolved. On the other hand, polyamide resin also has better gas barrier properties than PET, and is also superior in moldability, so by laminating PET with modified PAR, a multilayer container with excellent heat resistance and gas barrier properties can be obtained. Possible, but PET and denaturation
The adhesion between PAR and polyamide is extremely poor, and an adhesive layer is required between them to create a multilayer container. This requires the development of complex and difficult molding technology, and a suitable adhesive has not yet been found, so multilayer containers with this structure have not yet been put into practical use. This is the current situation. (Problems to be Solved by the Invention) Despite the fact that it is highly predicted that a composite of PET/modified PAR/polyamide will yield a high-performance multilayer container with excellent heat resistance and gas barrier properties. The biggest reason for the delay in its practical application is the problem of adhesion between these materials. Although PET and modified PAR exhibit very strong adhesion, they do not adhere at all to the polyamide layer. Therefore, in order to manufacture a multi-layer container with such a structure, an appropriate adhesive layer is required, but providing such an adhesive layer makes the multi-layer structure more complicated and requires molding technology. To solve this problem, there is a strong desire to develop a technology that provides adhesion between modified PAR and polyamide layers without providing an adhesive layer. (Means for Solving the Problems) The present inventors have conducted extensive research in order to solve these problems and develop a multilayer container that has excellent rigidity, heat resistance, and gas barrier properties, and can also be provided with transparency if necessary. As a result, we have arrived at the present invention.That is, the present invention provides a heat-resistant material comprising 10 to 90% by weight of a sulfonic group-containing polyester and 90 to 10% by weight of an aromatic polyester between a polyester resin layer mainly composed of PET or PET and a polyamide resin layer. It is a heat-resistant, gas barrier multilayer container characterized by providing a resin layer, and furthermore, the sulfion group-containing polyester used in the heat-resistant adhesive made of a sulfon group-containing polyester and an aromatic polyester is a total acid component in the adhesive composition. PET (hereinafter referred to as sulfon group-containing modified PAR) is copolymerized with 0.5 to 10 mol% of sodium sulfoisophthalic acid and/or sodium sulfo terephthalic acid. The PET used in the present invention is a polyester whose main repeating unit is ethylene terephthalate, and contains phthalic acid, isophthalic acid, hexahydrophthalic acid, Dicarboxylic acids such as naphthalene dicarboxylic acid, adipic acid, and sebacic acid, polyhydric carboxylic acids such as trimellitic acid and pyromellitic acid, or oxyacids such as P-oxybenzoic acid can be used as the acid component, and total alcohol 10 ingredients
1,2-propanediol in an amount of up to mol%;
Dihydric alcohols such as 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, diethylene glycol, triethylene glycol, cyclohexanedimethanol, trimethylolpropane,
Polyhydric alcohols such as triethylolpropane and pentaerythritol can be used as the alcohol component. PET like this
is obtained by a conventional melt polycondensation reaction, and if necessary, the degree of polymerization can be further increased by a solid phase polymerization reaction. Examples of the polyamide used in the present invention include polycapramide, polylaurinlactam, polyhexamethyleneadipamide, poly11-aminoundecanoic acid, poly-methaxylyleneadipamide, poly-paraxylyleneadipamide, etc. For example, these may be used alone, as a copolymer, or as a mixture. The sulfon group-containing polyester in the sulfon group-containing modified PAR, which is one of the constituent components of the heat-resistant adhesive layer of the present invention, contains sodium sulfoisophthalic acid and sodium sulfonate as part of the acid component in the polyester. It can be easily obtained by a conventional melt polycondensation reaction using terephthalic acid, and when a polymer with a high degree of polymerization is required, a solid phase polymerization reaction can also be used. If the amount of copolymerization of sodium sulfoisophthalic acid and/or sodium sulfo-terephthalic acid is 0.5 mol% or more based on the total acid component in the sulfon group-containing modified PAR, the amount of copolymerization of sodium sulfoisophthalic acid and/or sodium sulfioterephthalic acid is 0.5 mol % or more based on the total acid component in the sulfon group-containing modified PAR. and can have sufficient adhesion to polyamide. In addition, at a copolymerization amount of 10 mol% or more, the adhesive force reaches saturation, and no further effects can be expected, and at the same time, hygroscopic effects due to sulfon groups occur, which also has a negative effect on the gas barrier properties of polyamide. do not have. The basic properties of sulfonate group-containing polyester are:
It is desirable that the polyester be as close to PET as possible in terms of heat resistance, processability, etc., and this can be solved by using PET containing sulfone groups as the polyester.
Similarly, the aromatic polyester in the modified PAR containing a sulfonate group is composed of an aromatic dicarboxylic acid or a derivative thereof and a dihydric phenol or a derivative thereof. Preferred aromatic dicarboxylic acids include terephthalic acid, isophthalic acid, and the like, and mixtures thereof are particularly preferred in terms of melt processability and overall performance. In the case of such a mixture, the mixing ratio is not limited, but preferably terephthalic acid/isophthalic acid = 9/1 to 1/9 (weight ratio), particularly 7 in terms of melt processability and balance of performance. /3 to 3/7 (weight ratio) is desirable. Divalent phenol has the following general formula where R ₁ , R ₂ , R ₃ , R ₄ , R′ ₁ , R′ ₂ ,
R′ ₃ and R _{′ 4} are selected from the group consisting of a hydrogen atom, a halogen atom, a hydrocarbon group, and a halogenated hydrocarbon group; The alkylidene group may be substituted with one or more halogen groups). The dihydric phenol used in the present invention includes:
For example, 2,2-bis(4-hydroxyphenyl)
-propane, 2,2-bis(4-hydroxy-
3,5-dibromophenyl)-propane, 2,2
-bis(4-hydroxy-3,5-dichlorophenyl)-propane, 4,4'-dihydroxyphenyl sulfone, 4,4'-dihydroxydiphenyl ether, 4,4'-dihydroxydiphenyl sulfide, 4,4'-dihydroxydiphenylketone,
4,4'-dihydroxydiphenylmethane, 2,2
-bis(4-hydroxy3,5dimethylphenyl)propane, 1,1-bis(4-hydroxyphenyl)-ethane, 1,1-bis(4-hydroxyphenyl)cyclohexane, 4,4'-dihydroxy Diphenyl, benzoquinone, etc. These may be used alone or as a mixture. In addition, these divalent phenols are para-substituted products,
Other isomers may be used, and ethylene glycol, propylene glycol, etc. may be used in combination with these dihydric phenols. The most typical divalent phenols are 2,
2-bis(4-hydroxyphenyl)propane,
It is commonly called bisphenol A. Such aromatic polyesters are produced by various methods such as solution polymerization, melt polymerization, and interfacial polymerization. Sulfon group-containing modified PAR can be obtained by extruding this sulfon group-containing polyester and an aromatic polyester using a melt extruder, or by stirring and mixing them while melting them in a reaction vessel equipped with stirring blades. A randomization promoting catalyst such as sodium acetate may be added in order to promote randomization due to the transesterification reaction that occurs during the process and to obtain a uniform polymer alloy. Such a modified PAR containing a sulfone group exhibits a higher glass transition temperature Tg and has improved heat resistance as the amount of aromatic polyester increases. The basic unit of the multilayer container according to the present invention is PET/modified PAR containing sulfon group/polyamide, and optionally PET/modified PAR containing sulfon group/polyamide/modified sulfon group containing
It can have a five-layer structure such as PAR/PET, or a multi-layer structure of more than that. Such a multilayer container can be obtained by heating a coextruded multilayer sheet having the above structure and then subjecting it to deep drawing processing such as vacuum forming or pressure forming. Direct blow molding by coextrusion or bottle molding by biaxial stretch blow molding using a co-injection multilayer preform can also be used. Furthermore, after cutting the coextruded multilayer pipe to a certain length, the ends of the pipe are heated and compression molded to form the mouth and weld the bottom.The resulting multilayer preform is then biaxially stretched and blow molded into a bottle. This method is also an effective method. (Function) In the present invention, PET which has no mutual adhesive force at all
By providing an adhesive layer of sulfonated modified PAR with excellent adhesion to both PET and polyamide, it is possible not only to create a multilayer container that integrates PET and polyamide, but also to create a multilayer container that integrates PET and polyamide. Utilizing the heat resistance of PAR, this multilayer sheet is provided with heat resistance in addition to the many advantages of PET and the gas barrier properties of polyamide. The amount of sulfonate group-containing modified PAR necessary for imparting such heat resistance to 3% or more of the total weight of the container can sufficiently exhibit its effect. In addition, such a multilayer container is such that each of its constituent components is stretched 2
The material is selected from materials with excellent subsequent processability, which makes it extremely easy to form containers.Furthermore, when considering alternative uses for metal cans and glass containers, it can be used in ways that have not been possible with PET containers themselves until now. It can be said with certainty that this is a revolutionary container that has both heat resistance and gas barrier properties. (Example) Next, the present invention will be specifically explained with reference to Examples, but the present invention is not limited thereto. Example 1 An extreme clay having a composition of 97.5 mol% terephthalic acid, 2.5 mol% 5-sodiumsulfoisophthalic acid, and 100 mol% ethylene glycol, measured at 20°C in a mixed solvent of equal weight of phenol/tetrachloroethane. A polyester containing 0.70 sulfone groups was obtained by a conventional melt polycondensation reaction. On the other hand, it consists of terephthalic acid/isophthalic acid (mixed molar ratio 1) and bisphenol A;
An aromatic polyester having a logarithmic viscosity of 0.60 measured at 25° C. in a 6/4 mixed solvent of tetrachloroethane was prepared. This sulfon group-containing polyester and aromatic polyester are melt-blended in a ratio of 6:4, and the sulfon group-containing modified polyester has a Tg of 99°C.
Got PAR. At this time, the amount of 5-sodium sulfoisophthalic acid based on the total acid components was 1.5 mol%.
It is. Separately, PET with an intrinsic viscosity of 1.0 and polymethaxylylene adipamide (Mitsubishi Gas Chemical Co., Ltd. Reny)
6001), thoroughly dried these materials, and extruded them through a multilayer die using three dedicated extruders to form PET (320μ)/modified PAR containing sulfonate groups (40μ)/polymethaxylylene adiper. Mido (80μ) / Modified PAR containing sulfonate group (40μ) /
A 5-layer PET (320μ) sheet with a pressure of 800μ was obtained. There was no thickness unevenness between each layer, and the adhesion was so strong that it could not be peeled off. This sheet was heated at 140° C. for 5 seconds and then formed into a cup with a diameter of 100 mm and a depth of 40 mm by vacuum forming, and a uniformly stretched transparent product was obtained. When this cup was filled with hot water and the degree of deformation was observed, no deformation occurred at all up to 85°C. We also measured the carbon dioxide permeability of the film cut out from this container.
Compared to 12.8cc・mm/24hr・m ²・atm of PET alone
It was confirmed that the fuel consumption had been significantly improved to 1.3cc・mm/24hr・m ²・atm. Example 2 Using each resin used in Example 1, a multilayer blow molding machine was used to mold PET (230 μ) / modified PAR containing sulfon group (20 μ) / polymethaxylylene adipamide (40 μ) / modified PAR containing sulfon group (20 μ). )/
A 500ml bottle with a body wall made of PET (190μ) was molded. This bottle did not deform when filled with hot water at 85°C, and the amount of carbon dioxide permeation through the film cut from the body was good at 1.8cc·mm/24hr·m ² ·atm. Example 3, Comparative Examples 1 to 2 Bottles were molded according to the method of Example 2, but with different compositions of the polyamide and adhesive layer,
The results shown in Table 1 were obtained.

[Table] In the table, NaSIPA-PET is PET copolymerized with 2.5 mol% of 5-sodium sulfoisophthalic acid.
Also, PAR indicates aromatic polyester.
The structure of the bottle is the same as in Example 2, but only in Comparative Example 2, no adhesive was used and PET
It has a three-layer structure of (230μ)/polymethaxylylene adipamide (40μ)/PET (190μ). The heat-resistant temperature of the container was determined to be a temperature at which no deformation occurs when filled with hot water. (Effect of the invention) As is clear from the above, the requirements of the present invention are satisfied.
A multilayer container having a structure in which the basic unit is PET/modified PAR containing a sulfonate group/polyamide has excellent interlayer adhesion, and it is possible to obtain a container having excellent gas barrier properties and heat resistance.

Claims (1)

[Scope of Claims] 1. A heat-resistant adhesive layer consisting of 10 to 90% by weight of sulfonic group-containing polyester and 90 to 10% by weight of aromatic polyester is provided between polyethylene terephthalate or a polyester resin layer mainly composed of polyethylene terephthalate and a polyamide resin layer. A heat-resistant, gas-barrier multilayer container characterized by the provision of a heat-resistant and gas barrier multilayer container. 2. The sulfon group-containing polyester used in the heat-resistant adhesive made of the sulfon group-containing polyester and the aromatic polyester contains sodium sulfoisophthalic acid and/or sodium sulfonisophthalic acid with respect to the total acid component in the adhesive composition. The heat-resistant, gas barrier multilayer container according to claim 1, which is polyethylene terephthalate copolymerized with 0.5 to 10 mol% of terephthalic acid.