JPS62292434A - Heat-resistant gas barrier multilayer vessel - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] 3. Detailed Description of the Invention (Field of Industrial Application) The present invention is a novel heat-resistant product that enables the thermal filling of various foods such as soft drinks, seasonings, and alcoholic beverages.

This invention relates to gas barrier multilayer containers.

(Prior Art) Generally, linear polyester, particularly polyethylene terephthalate (hereinafter referred to as PIET), 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 the mainstream polyolefin containers such as polyethylene and polyvinyl chloride.

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 necessary to reduce weight by using plus deck. 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 bottleneck, greatly limiting its application.

As a means of improving the gas barrier properties and heat resistance of such PET S containers, we have developed a bottle in which PIET is coated with an MI layer of a heat-resistant resin composition (hereinafter referred to as modified PAR) consisting of an oxygen barrier resin, aromatic polyester, and PI'uT. is known (Japanese Unexamined Patent Publication No. 59-214047).

Gas barrier 1-type resins generally include ethylene vinyl alcohol copolymer, polyvinylidene chloride, and polyacrylonitrile resins, and these resins and P
Although the development of composite technology with IET is progressing steadily, 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 molding processability, so by MIMing PET with modified PAR, a multilayer container with excellent heat-resistant three-gas barrier properties can be obtained. However, the adhesion between Pr:T and modified PAR and polyamide is extremely poor, and an adhesive layer is required between them to form a multilayer container.

This required the development of complex and difficult molding technology.
Furthermore, because no suitable adhesive has been found, multilayer containers with such a structure have not yet been put into practical use.

(Problems to be Solved by the Invention) As described above, it is highly predicted that a highly functional multilayer container with excellent heat resistance and gas barrier properties can be obtained by combining Pr, T/modified PAR/polyamide. However, the biggest reason for the delay in its practical application is the problem of adhesion between these materials. Although PRT and modified PAR exhibit very strong adhesion, they do not adhere at all to the polyamide layer.

Therefore, in order to manufacture a multilayer container with such a structure, an appropriate adhesive layer is required.1 Providing a new adhesive layer makes the multilayer structure more complicated,
In order to make the molding technology difficult, there is a strong desire to develop a technology that provides adhesion between the modified PAR and the polyamide layer without providing an adhesive layer.

(Means for Solving the Problems) The present inventors conducted conceptual 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 is characterized in that a heat-resistant resin layer consisting of 10 to 90% by weight of sulfone group-containing polyester and 90 to 10% by weight of aromatic polyester is provided between the polyester resin layer used as PUT or a polyamide resin layer and the polyamide resin layer. 1 Furthermore, the sulfone group-containing polyester used in the heat-resistant adhesive comprising the sulfone group-containing polyester and the aromatic polyester has a soju A multilayer characterized by being l'1IiT (hereinafter referred to as sulfone group-containing modified +1AI+) copolymerized with 0.5 to 10 mol% of foisophthalic acid and/or sodium sulfoterefcuric acid. It is 2;

PpT used in the present invention is a polyester whose main (repeating center) is ethylene terephthalate, and phthalic acid, isophthalic acid, hexahydrofucric acid, knack dicarboxylic acid, etc. Dicarboxylic acids such as , 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 acid components, and total alcohol components 1,2-propanediol, ■, 3-propanediol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, diethylene glycol, triethylene glycol, cyclohexanediol in an amount of 10 mol% or less of Dihydric alcohols such as metatool, trimethylol-propane, triethylolpropane.

Polyhydric alcohols such as pentaerythritol can be used as the alcohol component. Such PRT can be obtained by a conventional melt polycondensation reaction,
If necessary, the degree of polymerization can be further increased by 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 sulfone group-containing polyester in the sulfone 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 sodum sulfoterephthalic acid as part of the acid components in the polyester. can be easily obtained by a conventional melt polycondensation reaction using
Furthermore, when a polymer with a high degree of polymerization is required, a solid phase m-polymerization reaction can also be used.

The combined amount of sodium sulfoisophthalic acid and/or sodium sulfoterephthalic acid is 0.5 with respect to the total acid component when the sulfone group-containing modified PAR is prepared.
If the amount is mol % or more, it can have sufficient adhesive strength to the adjacent layer PIT and polyamide. 10 more
When the co-m content exceeds mol%, the adhesive force reaches saturation, and no further effect can be expected, and at the same time, the hygroscopic effect of the sulfone group occurs, and the gas barrier of polyamide
It also does not give good results for characteristics.

What are the basic properties of sulfone group-containing polyester?

It is desirable that the polyester be as close to PIT as possible in terms of heat resistance, processability, etc., and this can be solved by using sulfone group-containing PET as the polyester. Similarly, the aromatic polyester in the sulfone group-containing modified PAR is composed of an aromatic dicarboxylic acid or its derivative and a dihydric phenol or its derivative. 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 should not be limited, but terephthalic acid/isophthalic acid=
9/1 to 1/9 (ffi amount ratio) is preferable.

Especially in terms of melt processability and performance balance, it is 7/3 to 3/7.
(ffil ratio) is desirable. Dihydric phenol is represented by the following general formula 1 where R+, Ra, Rco, R4, R'll
R″2.R′3.R′4 is selected from the group consisting of a hydrogen atom, a halogen atom, a hydrocarbon group, and a halogenated hydrocarbon group, and X is O, S, Sow, Cot 7Jl/Kil/
7 or an alkylidene group (if necessary, the alkylene or alkylidene group may be substituted with one or more λ rogene groups).

The dihydric phenol used in the present invention includes:

Example Eva 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'-dihydroxydiphenyl ketone, 4.4'-dihydroxydiphenylmethane, 2.2-bis(4-hydroxy) 3.5 dimethylphenyl)propane, 1.1-bis(4-hydroxyphenyl)-ethane. These include 1.1-bis(4-hydroxyphenyl)cyclohexane, 4゜4゛-dihydroxydiphenyl, and benzoquinone. These dihydric phenols may be used alone or as a mixture.Although these dihydric phenols are para-substituted, other isomers may also be used.
Furthermore, ethylene glycol is added to these dihydric phenols.

Propylene glycol or the like may be used in combination.

The most typical dihydric phenol is 2,2-bis(4-hydroxyphenyl)propane, commonly called bisphenol A. Such aromatic polyesters are solution polymerized and melt polymerized.

Manufactured by various methods such as interfacial polymerization. Sulfone group-containing modified PAR can be obtained by extruding this sulfone group-containing polyester and aromatic polyester using a melt extruder or by stirring and mixing them while melting them in a reactor 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 sulfone group-containing modified PAR exhibits a higher glass transition temperature Tg and has improved heat resistance as the number of aromatic polyesters increases.

The structure of the multilayer container according to the present invention is basically composed of PET/modified PAR containing sulfone groups/polyamide.

If necessary, r'ET/sulfone group-containing modified PA
R/Polyamide/Sulfone group-containing modified PAR/PIE
It is possible to have a 5WJ structure such as T or a multilayer structure of more than 5WJ.

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 coaxial stretch blow molding using a co-injection multilayer preform can also be used.

Furthermore, after cutting the coextruded multilayer pipe into a fixed length, first heating both ends of the pipe and forming a mouth and welding the bottom by IE compression molding, the resulting multilayer preform is biaxially stretched and blow molded into a bottle. This method is also an effective method.

(Function) In the present invention, an adhesive layer of sulfone group-containing modified PAH, which has excellent adhesion to both, is provided between PIET and polyamide, which have no adhesive strength to each other, thereby creating a multilayer structure that integrates PET and polyamide. Not only can it be used as a container, but the heat resistance of sulfone group-containing modified PAR can be used to impart heat resistance to this multilayer sheet in addition to the many advantages of PIET and the gas barrier properties of polyamide. be.

The amount of sulfone group-containing modified PAR necessary for imparting such heat resistance to 3% or more of the total weight of the container can sufficiently exhibit the effect. In addition, each of the constituent components of such a multilayer container is selected from materials with excellent secondary processing properties, making it extremely easy to form the container, and furthermore, it can be used as an alternative to gold B cans and glass containers. When you think about it, you can say with certainty that it is an epoch-making container that has both heat resistance and gas barrier properties that have never been possible with the PIET S container itself.

(Example) Next, the present invention will be specifically explained with reference to Examples, but the present invention is not limited thereto.

Example 1 Terefucuric acid 97.5 mol%, 5-sodumsulfoisophthalm m2.5 mol%, ethylene glycol 100
The ultimate clay has a composition of T-ru% and an extreme clay measured at 20°C in an equal weight mixed solvent of phenol/tetrachloroethane is 0.
A sulfone group-containing polyester of No. 70 was obtained by a conventional melting condensation reaction.

On the other hand, an aromatic polyester consisting of terephthalic acid/isofucric acid (mixed molar ratio 1) and bisphenol A and having a logarithmic viscosity of 0.60 as measured at 25 DEG C. in a mixed solvent of phenol/.dichloroethane=674 was prepared. This sulfone group-containing polyester and aromatic polyester are combined into 6
A sulfone group-containing modified PAR having a Tg of 99° C. was obtained by melt blending at a ratio of 4 to 4. At this time, the amount of 5-sodium sulfoisophthalic acid relative to the total acid components is 1.5
It is mole%.

Separately, prepare PUT with an intrinsic viscosity of 1.0 and polymethaxylylene adipamide (Nie 6001 manufactured by Mitsubishi Gas Chemical), and after thoroughly drying these materials, use three dedicated extruders for each to form a multilayer film. Extrude from the die, PI! T
(320 μ)/sulfone group-containing modified PAlil (
40μ)/polymethaxylylene adipamide (80,+)
)/Sulfone group-containing modified PAR (40μ”)/PE
A sheet with a thickness of 800μ and having a five-layer structure of T (320μ) 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 vacuum-formed to be directly printed! ! When molded into a cup with a thickness of 100 mm and a depth of 40 mm, a uniformly stretched and transparent product could be 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.

In addition, we measured the carbon dioxide permeability of the film cut out from this container and found that it was 12.8 cc-
mm/1.3cc・m compared to 24hr-g-atm
It was confirmed that the speed had improved to 24hr-rd-atm and 24hr-rd-atm.

Example 2 PUT (230μ)/sulfone group-containing modified P using a multilayer blow molding machine using each resin used in Example 1
AR (20 μ)/polymethaxylylene adipamide (40
μ)/Sulfone group-containing modified FAI? (20μ)/P
ET (190μ) (7) 500I with body wall structure
Ill-no-hottle was molded.

This bottle did not deform when filled with 85°C hot water, and the amount of carbon dioxide gas permeated through the film cut from the body was 1.8.
It was good at cc-mm/24hr-rd-atm.

Example 3. Comparative Examples 1-2 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 1 In the table, Na5IPA-PET represents PIET copolymerized with 2.5 mol% of 5-sodium sulfoisophthalic acid, and PAR represents 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 P[! T (230μ) / Polymethaxylylene adipamide (40μ) / PIET (
It has a three-stone structure of 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, 9 PE↑/ that satisfy the requirements of the present invention
A multilayer container having a structure in which the basic unit is a sulfone group-containing modified PAR/polyamide has excellent interlayer adhesion, and it is possible to obtain a container having excellent gas barrier properties and heat resistance.

Claims (2)

[Claims] (1) A heat-resistant adhesive layer made of 10 to 90% by weight of sulfone 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 multi-layer container. (2) The sulfone group-containing polyester used in the heat-resistant adhesive composed of the sulfone group-containing polyester and the aromatic polyester is The heat-resistant material according to claim 1, which is polyethylene terephthalate copolymerized with 0.5 to 10 mol% of terephthalic acid;
Gas barrier multilayer container.