JPS62246728A - Multilayer coextruded sheet and structure thereof - 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 (Field of Industrial Application) The present invention relates to a coextruded sheet and structure with excellent heat resistance and gas barrier properties. The present invention provides a coextruded multilayer sheet suitable for forming deep-drawn containers as well as multilayer containers formed therefrom.

(Prior art) Linear polyester, especially polyethylene terephthalate (hereinafter referred to as PI!T), has attracted attention as a material for various containers including bottles due to its excellent mechanical and chemical properties. Special Public Service No. 44-5107
This is typified by the method described in the Publication No. ・Pf! Deep-drawn containers made from T-sheets are also in increasing demand as containers with excellent rigidity and gas barrier properties.

However, improvements in packaging technology and expansion of packaging applications require the addition of even higher functionality to PUT containers.In particular, when considering alternative uses for metal cans and glass containers, it is necessary to use plastics to reduce weight and make them transparent. Although it has many advantages in terms of performance and safety, its lack of performance in terms of gas barrier properties and heat resistance has been a bottleneck, greatly limiting the development of its applications.

As a means of improving the gas barrier properties and heat resistance of such PET containers, PI! A partially saponified resin of ethylene/vinyl acetate copolymer (hereinafter referred to as +!VOI+), which is a material with even better gas barrier properties than T, or a vinyl resin mainly composed of this and PI! Polycarbonate and Pt, which are materials with even better heat resistance than T! A resin composition consisting of T (hereinafter referred to as modified PC) is PET.
A multilayer bottle made by co-injection and two-wheel stretch blow molding is conceivable, but a multilayer sheet with such a structure with excellent heat resistance and gas barrier properties and containers molded from it have not yet been put into practical use.

(Problem to be solved by the invention) In this way, PI! T/l! Vol! /Although it is highly predicted that the composite of modified PC will provide high functionality such as heat resistance and gas barrier, the main reason for the delay in its practical application is the problem of adhesion between these materials. be. While PET and modified PC each have a non-polar molecular structure and exhibit excellent mutual adhesion under coextrusion conditions, [! ν0■ has a polar molecular structure with a hydroxyl group with large molecular cohesive energy, and therefore the pH
↑ and direct adhesion to modified PC is not possible at all.

Therefore PI! T/I! Although an adhesive layer is essential for forming a multilayer sheet of VOH/modified PC, an adhesive suitable for forming such a sheet has not yet been found. Of course just a PI! T and EVO
If the purpose is to adhere H, acid anhydride group-containing polyolefin, epoxy group-containing polyolefin, or polyurethane adhesives have already been put into practical use.

In addition, the development of adhesives based on polyamides and polyesters is actively progressing, but adhesives for coextruded multilayer sheets intended for secondary processing such as deep drawing require a It goes without saying that secondary processability such as flexibility and suitability for stretching process, as well as transparency may be required.

However, it is necessary to improve adhesion (through modification techniques such as various copolymerizations and polymer alloys, it is a general tendency that the moldability decreases as the degree of modification progresses; 5- Difficulty in balancing PET /EVOI+/
This can be said to be one of the major reasons for delaying the practical application of highly functional multilayer sheets of modified PC.

(Means for Solving the Problems) The present inventors have solved the above problems, and have developed a material that has excellent rigidity, heat resistance, and gas barrier properties, can maintain transparency if necessary, and is also capable of deep drawing processing. In order to develop a coextruded multilayer sheet that is also provided with stretching and secondary processability, the present invention was arrived at as a result of extensive research, particularly regarding the adhesive layer.

That is, the present invention is a multilayer sheet having a structure in which a two-layer adhesive layer is provided between PET and EVOHO.

The PET side of the adhesive layer is a resin composition consisting of 10 to 90% by weight of sulfone group-containing polyester and 90 to 10% by weight of polycarbonate (hereinafter referred to as sulfone group-containing modified P).
It's called C. ) and I! This is a coextruded multilayer sheet characterized in that the Volt side is made of polyamide.

Furthermore, the sulfone group-containing polyester used in the sulfone group-containing modified PC is
Sodium sulfoisophthalic acid and/or sodium sulfoterephthalic acid is 0% of the total acid components in
．． This is a coextruded multilayer sheet characterized in that the PUT is copolymerized to have a content of 5 to 10 mol %, and the polyamide is a copolymerized polyamide containing 5 to 30 mol % of a nylon 66 component.

Furthermore, it is a structure molded from these coextruded multilayer sheets.

The PET used in the present invention is a polyester whose main repeating unit is ethylene terephthalate, with phthalic acid in an amount of 10 mol% or less of the total acid component.

Dicarboxylic acids such as isophthalic acid, hexahydrophthalic acid, 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 as acid components. It is possible to use 1.2-propanediol, 1.3-propanediol, 1.4-butanediol, 1.6-hexanediol, neopentyl glycol in an amount of 10 mol% or less of the total alcohol component. , diethylene glycol, triethylene glycol, dihydric alcohols such as cyclohexane dimetatool, trimethylolpropane, trimethylolpropane.

Polyhydric alcohols such as pentaerythritol can be used as the alcohol component. Such PUT is obtained by a melt polycondensation reaction by a conventional method,
If necessary, the degree of polymerization can be further increased by solid phase polymerization reaction.

EVOH used in the present invention is a crystalline polymer obtained by saponifying a random copolymer of ethylene/vinyl acetate represented by the trade name "EVAL".

It has polar hydroxyl groups and exhibits extremely excellent gas barrier properties due to its large molecular cohesive energy.

The sulfone group-containing polyester in the sulfone group-containing modified PC, which is one of the constituent components of the adhesive layer of the present invention, contains sodium sulfoisophthalic acid and sodium sulfoterephthalic acid as part of the acid component in the polyester. When a polymer with a high degree of polymerization is required, a solid phase polymerization reaction can also be used.

The total Jiff amount of the sodium sulfoisophthalic acid and/or the sodium sulfoterephthalic acid is 0.0% relative to the total acid component when the modified sulfone group-containing PC is prepared.
If the content is 5 mol % or more, sufficient adhesive strength can be obtained for the adjacent layers of PET and polyamide. Also 1
At a copolymerization amount of 0 mol% or more, the adhesive strength reaches saturation,
No further effect can be expected, and at the same time the hygroscopic effect of the sulfone group occurs, and t! VOH gas barrier
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 PET as possible in terms of heat resistance, processability, etc., and this can be solved by using sulfone group-containing PE↑ as the polyester. Similarly, the polycarbonate in the sulfone group-containing modified PC is a 4,4-dioxydiallylalkane polycarbonate, such as bis(4-hydroxyphenyl)methane, bis(,4
-hydroxyphenyl)ethane, 2.2bis(4-hydroxyphenyl)propane, bis(4-hydroxy-3
, 5-dichlorophenyl)methane, 2.2bis(4-hydroxy-3,5-')methylphenyl)propane, bis(4-hydroxyphenyl)phenylmethane, etc.
It is a polycarbonate obtained from 4-dioxydiphenylalkane and phosgene or diphenyl carbonate.

Sulfone group-containing modified PC can be obtained by extruding this sulfone group-containing polyester and polycarbonate using a melt extruder or by stirring and mixing them while melting in a reaction can with stirring blades. A suitable randomization promoting catalyst may be added in order to promote randomization due to the transesterification reaction that occurs and to obtain a uniform polymer alloy.

Such sulfone group-containing modified PC exhibits a higher glass transition temperature Tg and improves heat resistance as the amount of polycarbonate increases.

The polyamide which is another component of the adhesive layer of the present invention is selected from polycabramide, polylaurinlactam, polyhexyl-methyleneadipamide, poly-11-aminoundecanoic acid, and the like. These may be used alone, as a copolymer, or as a mixture, but a nylon 6°66 copolymer polyester containing 5 to 30 M% of a nylon 66 component is particularly preferred.

The structure of the multilayer sheet according to the present invention is obtained by extruding PET/sulfone group-containing modified PC/polyamide/BVOH as a basic unit from a multilayer gouey using four extruders dedicated to each resin. Group-containing modified PC/polyamide/l! Vol+/Polyamide/Sulfone group-containing modified PC/PRT 7M structure.

Furthermore, if necessary, a multilayer structure with more layers can be formed.

The multilayer sheet obtained by the present invention can be heated at a temperature range of 20 to 50°C higher than the 'rg of the sulfone group-containing modified PC, and then subjected to vacuum forming or pressure forming to easily improve rigidity, gas barrier properties, and heat resistance. It is important to have a good container for this purpose.

(Function) In the present invention, PET and RVO have no adhesive force to each other.
A two-layer adhesive layer is provided between H, one of which is made of polyamide with excellent adhesion to Ev011,
By making the other layer a sulfone group-containing modified PC that has excellent adhesion to both I'ET and polyamide, l'E
Not only can it be made into a multi-story sheet that integrates T and l1tVO11, but also a modified p
By utilizing the heat resistance of c, this multilayer sheet is provided with heat resistance in addition to the many advantages of PET and the gas barrier properties of EVOH.

The amount of sulfone group-containing modified PC necessary for imparting such heat resistance to 3% or more of the total sheet weight can sufficiently exhibit the effect.

In addition, each of the constituent components of such a multilayer sheet is selected from materials that are excellent in secondary drawing processability such as deep drawing processing,
For this reason, it can be molded extremely easily, but when considering alternative uses for metal cans and glass containers, this container is a revolutionary product that combines heat resistance and gas barrier properties that were previously not possible with PET containers themselves. It can be said with certainty that it is a typical container.

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

Example 1 Terephthalic acid 97.5 mol%, 5-sodium sulfoisophthal #3.0 mol%, ethylene glycol 100
A sulfone group-containing polyester having an ultimate clay of 0.70 as measured at 20°C in a mixed solvent of equal weights of phenol/tetrachloroethane was subjected to a melt polycondensation reaction using mol % by a conventional method.

This sulfone group-containing polyester and polycarbonate were melt-blended at a ratio of 5:5 to obtain a sulfone group-containing modified PC having a Tg of 99°C. At this time, the amount of 5-sodium sulfoisophthalic acid relative to the total acid components is 1
．． It is 5 mol%.

Separately, nylon 6°6 contains 15% by weight of nylon 66 component and has a relative viscosity of 4.5 as measured at 25°C in 96% concentrated sulfuric acid.
6 copolymer polyamide and P[! with an intrinsic viscosity of 1.0] MT measured at 190°C for 10 minutes at T and load 2160g
Prepare IOH (Eval EP-F manufactured by Kuraray) with a melt index) value of 1.40 g, thoroughly dry these materials, and then extrude them through a multilayer goo using four extruders dedicated to each, PUT ( 300μ)/sulfone group-containing modified PC (40μ)/copolymerized polyamide (2
0μ> / [EVOH (8 (lu) / copolymerized polyamide (20μ) / sulfone group-containing modified PC (40μ) /
A 7-layer PET (300μ) sheet with a thickness of 800μ was obtained. There was no thickness unevenness between the layers, and although the sheet was cloudy, it was translucent, and the layers were so firmly adhered that they could not be separated.

This sheet was heated at 140° C. for 5 seconds and then formed into a cup with an IN diameter of 100 mm and a depth of 40 mm+ by vacuum forming, resulting in a uniformly stretched transparent product. When this cup was filled with hot water and the degree of deformation was observed, no deformation occurred up to 85°C. In addition, the oxygen gas permeability of the film cut out from this container was measured using a measuring device manufactured by Moran Control, and it was 1.3 cc-mm/24 of PET alone.
1/2 or more compared to hr-1-atm = 14-lower 0.6 cr, -mm/24hr-nf ・at
It was confirmed that the value was m.

Example 2. Comparative Examples 1-2 The results shown in Table 1 were obtained according to the method of Example 1, except that the composition of the adhesive layer was changed.

Table 1 Na5IP^-Pl in the table! T indicates PUT copolymerized with 3.6 mol% of 5-sodium sulfoisophthalic acid, and PC indicates polycarbonate. Also, the structure of the multilayer sheet is 7 layers as in Example 1, so the thickness of each layer in the table is I! The thickness of the layers on both sides of the VOH layer is shown.

The heat-resistant temperature of the container was determined to be a temperature at which no deformation occurs when filled with hot water.

(Effects of the Invention) As is clear from Example 1.2, a PI that satisfies the requirements of the present invention! The coextruded multilayer sheet with T/sulfone group-containing modified PC/polyamide/EVOII as basic units has excellent extrusion moldability, uniformity, and adhesion between two layers, and containers molded from this sheet have excellent gas barrier properties. - property and excellent heat resistance corresponding to the heat resistance of the sulfone group-containing modified PC.

On the other hand, when the modified PC does not have a sulfone group as in Comparative Example 1, there is no adhesive force between it and the polyamide, and therefore peeling occurs during sheet extrusion or deep drawing, resulting in a significant decrease in productivity and at the same time, the heat resistance of welding However, the expected effect cannot be obtained.

Further, as in Comparative Example 2, when only sulfone group-containing PRT is used, workability and productivity are excellent, but heat resistance cannot be imparted.

As is clear from the above examples and comparative examples, coextruded multilayer sheets and containers with excellent heat resistance and gas barrier properties can be easily obtained by the present invention.

Claims (3)

[Claims] (1) A two-layer adhesive layer is provided between polyethylene terephthalate or a polyester resin layer mainly composed of polyethylene terephthalate and a partially saponified resin of ethylene/vinyl acetate copolymer or a vinyl resin layer mainly composed of polyethylene terephthalate. A multilayer sheet having a structure, in which the polyester resin layer side of the adhesive layer is a resin composition made of 10 to 90% by weight of sulfone group-containing polyester and 90 to 10% by weight of polycarbonate, and the vinyl resin layer side is made of polyamide. A coextruded multilayer sheet characterized by: (2) The sulfone group-containing polyester used in the resin composition consisting of the sulfone group-containing polyester and polycarbonate contains sodium sulfoisophthalic acid and/or sodium sulfoterephthalic acid relative to the total acid components in the resin composition. Polyethylene terephthalate copolymerized to a concentration of 0.5 to 10 mol%,
The coextruded multilayer sheet according to claim 1, wherein the polyamide is a copolyamide containing 5 to 30% by weight of a nylon 66 component. (3) An adhesive consisting of two layers between polyethylene terephthalate or a polyester resin layer mainly composed of polyethylene terephthalate and a partially saponified resin of ethylene/vinyl acetate copolymer or a vinyl resin layer mainly composed of this. A multilayer sheet having a structure in which a polyester resin layer side of the adhesive layer is made of a sulfone group-containing polyester of 10 to 90%.
A structure formed from a coextruded multilayer sheet, which is a resin composition consisting of 90 to 10% by weight of polycarbonate, and whose vinyl resin layer side is polyamide.