JPH08217934A - Thermoplastic resin composition and its use - Google Patents

Abstract

PURPOSE: To improve the softness, processibility, impact strength, tear strength, pinhole resistance, etc., of an ethylene-vinyl alcohol copolymer without reducing its clarity. CONSTITUTION: This compsn. comprises 50-85 pts.wt. ethylene-vinyl alcohol copolymer, 10-40 pts.wt. ionomer of an ethylene-unsatd. carboxylic acid copolymer contg. 4-15mol% unsatd. carboxylic acid units, and 1-25 pts.wt. polyamide.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermoplastic resin composition excellent in gas barrier properties, impact resistance, pinhole resistance, stretchability, drawability, transparency and the like, and uses thereof.

[0002]

2. Description of the Related Art Ethylene / vinyl alcohol copolymers having a high vinyl alcohol content are widely used as food packaging materials because of their excellent transparency and gas barrier properties. However, since the copolymer is poor in flexibility, workability, spreadability, etc., it is rarely used as a monolayer film. For example, when this copolymer is formed into a film by an inflation method, there are drawbacks in that vertical wrinkles are likely to occur before and after the pinch roll, and the allowable range of molding conditions for obtaining a satisfactory product is narrow. Further, when the film is repeatedly bent or otherwise deformed, a pin pole is likely to be formed. Such a drawback can be improved by blending an ethylene polymer having excellent flexibility and processability,
In many cases, the transparency of the ethylene / vinyl alcohol copolymer is greatly impaired, and it has not been widely adopted.

For example, JP-A-49-107351 discloses that flexibility is improved by blending an ionomer with an ethylene / vinyl alcohol copolymer. Since the purpose of this proposal is to improve the adhesion of the copolymer to polyolefin, it discloses a technique of further blending a considerable amount of polyamide. In this proposal, no consideration is given to transparency and no mention is made of the composition of the ionomer.

Similarly, an invention focusing on the adhesiveness with a polyolefin is disclosed in Japanese Patent Application Laid-Open No. 50-103582, and the same composition and polyolefin are used except that the polyamide content is smaller than that of the previous proposal. Discloses a laminated container. Similarly, no consideration is given to transparency, and zinc ionomers and sodium ionomers can be used as ionomers, but details thereof are not disclosed. Specifically, only an example using Surlyn 1652 is shown.

According to the studies by the present inventors, if an ionomer is added to an ethylene / vinyl alcohol copolymer,
The flexibility and processability are improved, but the transparency is significantly impaired. Further, as shown as a specific example in JP-A-50-103582, Surlyn 1652 and polyamide are added to ethylene / vinyl alcohol copolymer. It has been found that even in a system in which is blended, the flexibility and processability are improved, but the transparency is significantly impaired.

[0006]

Therefore, the present inventors have made earnest studies on a formulation that improves the above-mentioned drawbacks of the ethylene / vinyl alcohol copolymer and does not impair the transparency so much. As a result, when a predetermined amount of an ionomer of an ethylene / unsaturated carboxylic acid copolymer having a high unsaturated carboxylic acid content and a polyamide are blended, flexibility, processability, and impact resistance can be achieved without sacrificing transparency so much. It was found that improvements in tear strength, pinhole resistance, etc. can be achieved.

Therefore, the object of the present invention is to
The object is to improve the drawbacks of vinyl alcohol copolymers without significantly impairing their transparency.

[0008]

DISCLOSURE OF THE INVENTION The present invention is an ionomer of an ethylene / unsaturated carboxylic acid copolymer having an ethylene / vinyl alcohol copolymer content of 50 to 85 parts by weight and an unsaturated carboxylic acid content of 4 to 15 mol%. It relates to a thermoplastic resin composition comprising 10 to 40 parts by weight and 1 to 25 parts by weight of polyamide.

[0009]

In the present invention, among ionomers, an ionomer having a relatively high unsaturated carboxylic acid content, that is, an ethylene / unsaturated carboxylic acid copolymer having an unsaturated carboxylic acid content of 4 to 15 mol% is selected. The remarkable feature is that this is blended with an ethylene / vinyl alcohol copolymer in combination with a polyamide.

That is, by blending the above components, ethylene.
Flexibility, impact resistance, processability, etc. can be improved without significantly reducing the transparency of the vinyl alcohol copolymer.

It is particularly important for the ionomer used in the present invention that the unsaturated carboxylic acid content is in the range of 4 to 15 mol% in order to maintain excellent transparency and improve impact resistance. . When the unsaturated carboxylic acid content is lower than the above range, the transparency and impact resistance tend to be lowered (see Comparative Examples 1 and 2 described later), and when the unsaturated carboxylic acid content is too high, the resistance is also high. Impact resistance tends to decrease.

On the other hand, the polyamide used in the present invention is a component for compatibilizing the ethylene / vinyl alcohol copolymer and the ionomer, and the combination of the ionomer and the polyamide reduces the optical properties such as transparency. It is possible to improve flexibility, impact resistance, workability, etc. without performing the above.

That is, when the ionomer alone is blended with the ethylene / vinyl alcohol copolymer (see Comparative Example 6 described later), the transparency and the impact resistance are greatly reduced as compared with the unblended one. Further, when polyamide alone is blended (see Comparative Example 7 described later), impact resistance and workability are hardly improved, but by blending both in combination (see Examples 1 to 9 described later), It is possible to significantly improve the mechanical properties and workability without significantly reducing the transparency.

In the present invention, 50 to 85 parts by weight of ethylene / vinyl alcohol copolymer and 10 to 4 of ionomer are used.
It is also important to use 0 parts by weight and polyamide in an amount of 1 to 25 parts by weight, and when the amount of the ionomer used is less than the above range (see Comparative Example 3 described later), impact resistance and workability of If the improvement is insufficient and the amount is more than the above range (see Comparative Example 4 described later), the gas permeation resistance decreases. When the amount of polyamide used is less than the above range (see Comparative Example 3 or 6 described later), the impact resistance decreases, while when it is more than the above range (see Comparative Example 5 described later). In addition to making the composition difficult to process, it has the disadvantage of poor thermal stability.

According to the present invention, as described above, the ethylene / vinyl alcohol copolymer is blended with the specific ionomer and the polyamide in a predetermined amount, whereby the excellent gas barrier property and transparency of the copolymer are obtained. Impact resistance, flexibility, workability, pinhole resistance, without sacrificing
The deep drawability can be improved.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION The ethylene / vinyl alcohol copolymer used in the present invention has a vinyl alcohol content of 40 to
It is contained in a proportion of 85 mol%, preferably 50 to 75 mol%, and other monomers may be contained as long as they are about 10 mol% or less. The best way to obtain such a copolymer is to saponify an ethylene / vinyl acetate copolymer having a vinyl acetate content of 40 to 85 mol%, preferably 50 to 75 mol%, of 95% or more, preferably 98% or more. It is a method of performing saponification so that the frequency is constant. When the vinyl alcohol content in the copolymer exceeds the above range, heat resistance,
It is not preferable because the workability is deteriorated, and when it is less than the above range, the gas barrier property is deteriorated. As an ethylene / vinyl alcohol copolymer, 210 ° C, 21
Melt flow rate at a load of 60 g is 0.5 to 50
It is preferable to use g / 10 min, especially 1 to 20 g / 10 min.

In consideration of the transparency of the composition, the ionomer used in the present invention has an unsaturated carboxylic acid content of 4 to 15 in the ethylene / unsaturated carboxylic acid copolymer as a base.
Mol%, preferably 5 to 12 mol%, more preferably 6
It is within the range of 10 mol%. When the unsaturated carboxylic acid content is less than the above range, it is difficult to obtain a composition having excellent transparency and impact resistance. The higher the unsaturated carboxylic acid content, the more transparent the composition tends to be, but the impact resistance may be slightly reduced. Therefore, it is recommended to use the acid content as described above. preferable. In such a copolymer, 1
It may be copolymerized with about 2 mol% or less, preferably about 8 mol% or less of another monomer. Such a copolymer has a high temperature, a high pressure, ethylene, an unsaturated carboxylic acid,
Alternatively, it can be obtained by radically copolymerizing another monomer used as necessary.

Examples of the unsaturated carboxylic acid include acrylic acid, methacrylic acid, ethacrylic acid, maleic acid, monomethyl maleate, monoethyl maleate, maleic anhydride and the like, with acrylic acid or methacrylic acid being particularly preferred. Other monomers that may be contained in the copolymer include vinyl acetate, vinyl esters such as vinyl propionate, methyl acrylate, ethyl acrylate, isopropyl acrylate, isobutyl acrylate, and acrylic acid n. Butyl, 2-ethylhexyl acrylate, methyl methacrylate, isobutyl methacrylate, unsaturated carboxylic acid esters such as diethyl maleate, carbon monoxide and the like.

The metal ion in the ionomer is an alkali metal such as lithium, sodium or potassium, or an alkaline earth metal such as zinc, magnesium or calcium. Particularly, when zinc is used, it has excellent transparency and impact resistance. Well-balanced and preferable. The degree of neutralization in the ionomer is 5 to 100%, preferably 10 to 9
The range of 0, more preferably 30 to 70% is desirable.

The ionomer also has a temperature of 190.degree.
The melt flow rate under a load of 160 g is 0.05
It is preferable to use one having a content of -50 g / 10 minutes, particularly 0.5-5 g / 10 minutes.

As the polyamide used in the present invention, for example, nylon 6, nylon 66, nylon 610, nylon 612, nylon 11, nylon 12, nylon 6.
66 Copolymer, Nylon 6/12 Copolymer, Nylon 6
Examples thereof include a 6/12 copolymer, a nylon-6.610 copolymer, a nylon66.610 copolymer, and a nylon6.6T. These may have a molecular weight such that they can be formed into a film. Among these, it is preferable to use one having a melting point (DSC method) of 240 ° C. or lower, particularly 230 ° C. or lower. That is, if the melting point of the polyamide becomes too high, it becomes necessary to raise the molding temperature, and as a result, the possibility of increasing the thermal deterioration of the composition increases. The use of copolyamide is advantageous in lowering the melting point and improving the thermal stability.

In the present invention, when the total amount of the ethylene / vinyl alcohol copolymer, the ionomer and the polyamide is 100 parts by weight, the ethylene / vinyl alcohol copolymer is 50 to 85 parts by weight, preferably 60 to 50 parts by weight.
80 parts by weight, 10-40 parts by weight of ionomer, preferably 15-35 parts by weight, 1-25 parts by weight of polyamide, preferably 3-15 parts by weight. When the proportion of the ionomer used is less than the above range, the effect of improving the flexibility and pin pole resistance is small, and when the blending amount is more than the above range, the decrease in gas barrier property cannot be ignored, which is not preferable. Polyamide is
It acts as a compatibilizer for the ethylene / vinyl alcohol copolymer and ionomer, and minimizes the decrease in transparency. However, if used in an excessively large amount, the moldability of the composition will be impaired. It is said that

Various additives can be added to the composition of the present invention as required. Examples of such additives include antioxidants, heat stabilizers, weathering stabilizers, antistatic agents, lubricants, antiblocking agents, and the like. The composition of the present invention can also be blended with other polymers within a range that does not impair the properties.

The composition of the present invention can be easily obtained by melt-kneading each component with a usual melt-kneading apparatus. In order to obtain a molded article of the composition of the present invention, each component can be dry blended, melt-kneaded and directly molded. However, in the case of insufficient kneading, transparency and other physical properties may be impaired, so if the composition is melt-kneaded in advance into pellets and used in various moldings, molded articles with stable properties are obtained. It is possible because it is possible.

The composition of the present invention can be used for various packaging materials by taking advantage of the above-mentioned characteristics. Such packaging materials can be used in the form of films (unstretched films, shrink films, etc.), sheets, cups, trays, bottles, tubes, cans, paper cartons, bag-in-boxes and the like. These molded articles can be easily manufactured by known molding methods such as extrusion molding, injection molding, blow molding, and pressure molding.
Although these molding temperatures vary depending on the raw materials used, they are usually in the range of 190 to 240 ° C, and particularly preferably 200 to 230 ° C.

Such a molded article may be composed of only the composition of the present invention, or may have a multi-layered structure of two or more layers with other various base materials. Other substrates that can be laminated include, for example, polyethylene, polypropylene,
Polyolefins such as poly-1-butene and poly-4-methyl-1-pentene, ethylene / vinyl acetate copolymer, ethylene / (meth) acrylic acid ester copolymer,
Ethylene / (meth) acrylic acid copolymer or its ionomer, ethylene / (meth) acrylic acid / (meth)
Acrylic ester copolymer or its ionomer, ethylene copolymers such as ethylene / (meth) acrylic acid ester / maleic anhydride copolymer, polyamide, polyester, polyvinyl chloride, polyvinylidene chloride, polystyrene, paper, An aluminum foil, an aluminum vapor deposition film, etc. can be illustrated. Among these,
A laminated packaging material with a base material having at least one layer of an olefin polymer such as the above polyolefins and ethylene copolymers is particularly useful. When laminating the olefin polymer, a part or all of the olefin polymer may be preliminarily graft-modified with a monomer that imparts an adhesive property such as maleic anhydride, and such a graft-modified olefin polymer may be used as an adhesive layer. May be used to laminate an unmodified olefin polymer. When the resin composition of the present invention is used as an intermediate layer and sandwiched between an inner layer and an outer layer of a low hygroscopic resin such as an olefin resin, adverse effects due to moisture absorption of the intermediate layer (such as reduction of gas barrier property due to moisture absorption) are suppressed. Therefore, it is advantageous.

More specifically, the composition of the present invention is C, the above-mentioned olefin polymer is PO, the modified olefin polymer is modified PO, polyamide is PA, polyethylene terephthalate is PET, polystyrene is PS, and polyvinyl chloride is P.
When displayed as VC, PO / C, PO / modified PO / C, PO / C / PO, PO / modified PO / C / modified PO / PO, PET / C / PET, PS / C / PS, P
O / PA / C, PO / C / PA / PO, PO / paper / PO
A laminated structure such as / C / PO can be used.

[0028]

EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to these examples.

First, the method for preparing the resin composition, the method for processing the film, and the method for evaluating the physical properties of the film according to the present invention will be described below.

(1) Method for preparing resin composition Each resin composition shown in Tables 1 and 2 was blended according to the composition ratio shown in Table 3. The blending method includes a method in which the resin pellets are uniformly mixed in a solid state with a blender or the like under normal temperature (hereinafter referred to as a dry blend), or each resin is heated and kneaded and mixed using a single screw kneader. While extruding and pelletizing (hereinafter referred to as melt blending). The resin extrusion conditions for the melt blending are as follows. Extruder diameter: 40 mmφ, resin temperature: 230 ° C, resin extrusion rate: 10 kg / hr

(2) Film Processing Method Each composition blended by the above method (1) was prepared by an inflation film processing method with an extruder bore diameter of 30 mm or 50 mm. The inflation process was performed under the following conditions.・ Processing machine-1 30 mm diameter extruder, 50 mm diameter round die Processing resin temperature: 230 ° C, film thickness: 50 µm, film expansion ratio: 2.3, take-up speed: 3 m / min ・ Processing machine-2 50 mm diameter extruder, 150mm diameter round die processing resin temperature: 230 ° C, film thickness: 50μm, film expansion ratio: 2.4, take-up speed: 6m / min

(3) Evaluation Method of Physical Properties of Film Using the film prepared by the method of (2) above,
The following physical properties were measured according to each method and standard. The following evaluations were all carried out under the conditions of 23 ° C. and 50% relative temperature atmosphere, and the measurement results are summarized in Table 3. Measurement item Measurement method / standard Optical haze (cloudiness) JIS K-6714 Gloss (gloss) JIS Z-8471 Transformer (light transmissivity) ASTM D-1709 Oxygen permeability JIS Z-1707 Film impact Constant horizontal area Attach a 0.6 inch diameter anti-ball to the center of the circular film and measure the force when the film breaks. (Device used: Film Impact Tester, Toyo Seiki Co., Ltd.) Pinhole resistance The number of pinholes when the film is bent a predetermined number of times under the conditions of a twist angle of 440 degrees and a stroke of 152.4 mm are measured. (Equipment used: Toyo Seiki Co., Ltd. Gelbo flex measuring machine) Vacuum deep drawing processability Omori Kasei Co., Ltd. vacuum deep drawing tester was used to evaluate melt drawability. Film heating time: 2 seconds, vacuum drawing time: 3 seconds Drawing depth: 60 mm, film heating temperature: 140 ° C. Modulus JIS K6301 JIS No. 1 Dumbbell punched out a film sample and elongation of 2% at a pulling speed of 300 mm / min. The stress in the longitudinal and transverse directions of the film when measured as a percentage is measured. (Used equipment: Shimadzu Universal Testing Machine)

Example 1 and Comparative Example 8 In Example 1, various ionomers and EVs shown in Tables 1 and 2 were used.
21%, 70%, 9% by weight of OH and polyamide respectively
A composition prepared by the melt blending method described in the resin composition preparation method (1) at a composition ratio of 10% was formed into a film according to the film processing method (2) (processing machine-1 condition). The optical properties (haze, gloss, transformer), oxygen permeability, film impact, vacuum deep drawing workability, and modulus were measured according to the film physical property evaluation method of (3). On the other hand, in Comparative Example 8, the EVOH resin alone shown in Table 2 was evaluated by the same method as in Example 1 above. Table 3 shows the obtained results. As a result, the resin composition film of Example 1 showed almost the same optical properties and oxygen permeability as the EVOH single film of Comparative Example 8, but also in film impact, vacuum deep drawing processability and modulus (flexibility). A significant improvement effect was recognized.

Examples 3, 5 and 6, Comparative Examples 1 and 2 Evaluations were made in the same manner as in Example 1 except that the type of composition ionomer was changed as shown in Table 3. In Examples 3, 5 and 6, the same improvement effects as in Example 1 were observed, while in Comparative Examples 1 and 2, the film optical property or film impact was poor.

Examples 2 and 4 Example 2 is exactly the same as Example 1 and Example 4 is exactly the same as Example 3 except that each resin composition was prepared by the dry blending method. The film impact, oxygen permeability, vacuum deep drawing processability, and modulus are similar to those in Example 1, but the optical properties tend to be slightly worse than those prepared by the melt blending method.

Example 7 The same as Example 1 except that the resin composition ratios were changed as shown in Table 3.

[0037]

[Table 1]

[0038]

[Table 2]

Comparative Examples 3 to 5 The resin compositions were changed as shown in Table 3 and the same evaluations as in Example 1 were carried out. When the ionomer and polyamide composition amounts are too small relative to EVOH, melt stretchability and film impact are lowered as in Comparative Example 3, and conversely, when the ionomer and polyamide composition amount ratios are increased, As shown in Comparative Example 4, when the moldability of the film was lowered and the film could not be processed, or the proportion of the ionomer and the polyamide composition was increased, the oxygen permeability was significantly increased, which was not preferable.

Comparative Example 6 Polyamide was excluded from the composition resin to obtain a two-component composition of EVOH and ionomer. As a result, the optical properties and the film impact are significantly reduced, which is an unfavorable result.

Comparative Example 7 Ionomer was excluded from the composition resin to obtain a two-part composition of EVOH and polyamide. As a result, the film impact is reduced, the vacuum deep drawing processability is impossible, and the modulus is EV.
Increased over OH.

Example 8 The same resin composition as in Example 1 was used, and the extruder bore diameter was 50 m.
An inflation processing machine of m was used to prepare a film according to (2) Film processing method (processing machine-2).
The physical properties of the film showed the same level as in Example 1 even when the extruder scale was large, and good blown film processability and physical properties were observed.

Example 9 The same resin composition as in Example 2 was prepared in the same manner as the film processing method of Example 8. Even when the extruder scale was increased, the physical properties of the film were at the same level as in Example 2, and good blown film processability was recognized.

Comparative Example 9 For comparison, the EVOH resin shown in Table 2 was prepared by the same film processing method as in Example 8 and the physical properties of the film were evaluated.

In Examples 8 and 9 and Comparative Example 9, the pinhole resistance was measured according to the method described in the section (3) Evaluation of physical properties of film. As a result, as compared with Comparative Example 9, in Examples 8 and 9, the number of pinhole-generated bends was significantly increased, and the effect of improving the pinhole resistance was confirmed.

[0046]

[Table 3]

Example 10 The nylon of Example 1 was converted from 6-Ny to 6,12-Ny (U
A resin composition film was prepared in the same manner as in Example 1 except that the resin composition was changed to BE). Here, by using 6,12-Ny (UBE) having a lower melting point than 6-Ny, the resin temperature at the time of melt blending and film processing can be increased without substantially increasing the resin pressure or motor load of the extruder. It was possible to lower the temperature from 230 ° C to 210 ° C. This is effective in reducing thermal deterioration and thermal crosslinking during long-term operation during molding of the resin composition. The optical properties, oxygen permeability, film impact, pinhole resistance, and vacuum deep-drawing processability of the produced film were measured according to (3) film physical property evaluation method. The results, as shown in Table 4, show substantially the same oxygen permeability as that of the EVOH plain film of Comparative Example 8, while the film impact, the pinhole resistance, and the vacuum deep drawing processability are significantly improved. It was

[0048]

[Table 4]

Example 11 The nylon of Example 1 was converted from 6-Ny to 6,12-Ny (E
A resin composition film was prepared in the same manner as in Example 1 except that MS) was changed, and the obtained film was evaluated in accordance with (3) Film physical property evaluation method. The results, as shown in Table 4, show substantially the same oxygen permeability as that of the EVOH plain film of Comparative Example 8, while the film impact, the pinhole resistance, and the vacuum deep drawing processability are significantly improved. It was

Examples 12 and 13 The EVOH resin composition prepared in the same manner as in Example 1 was used as the outer layer, and the middle layer was a maleic anhydride-modified polyolefin resin (Admer NF520 manufactured by Mitsui Petrochemical Industry Co., Ltd.),
A three-layer cast film (55 μm thick laminated film having a thickness ratio of 15/10/30) in which the inner layer is a resin described in Table 5
It was manufactured under the molding conditions shown in Table 5 by using the multilayer coextrusion cast molding method. The optical properties and oxygen permeabilities of these films were measured according to the method (3) Evaluation of physical properties of film, and the results are shown in Table 5. The EVOH resin composition of the present invention is not only capable of producing a multilayer film by a usual molding method like EVOH, but also has good optical properties and oxygen permeation as in the case of the single layer film (Example 1). It was confirmed to indicate the degree.

[0051]

[Table 5] a) Extruder cylinder bore: outer layer / middle layer / inner layer = 50/50/65 mmφ, T-die: 500 mm width coat hanger type. b) Linear low-density polyethylene (Ultzex 202IL manufactured by Mitsui Petrochemical Co., Ltd.)

[0052]

EFFECTS OF THE INVENTION According to the present invention, the ethylene / vinyl alcohol copolymer is blended with a specified amount of a specific ionomer and a polyamide to sacrifice the excellent gas barrier property, transparency and the like of the copolymer. The impact resistance, the flexibility, the workability, the pinhole resistance, the deep drawability and the like can be improved without the use of the above. The composition of the present invention takes advantage of such characteristics, extrusion molding, injection molding, blow molding, vacuum molding,
By various molding methods such as pressure molding, film, sheet,
It can be molded into a container or the like.

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Claims (7)

[Claims] 1. An ethylene / vinyl alcohol copolymer 5
A thermoplastic resin composition comprising 0 to 85 parts by weight, an ionomer of an ethylene / unsaturated carboxylic acid copolymer having an unsaturated carboxylic acid content of 4 to 15 mol%, 10 to 40 parts by weight, and a polyamide, 1 to 25 parts by weight. . 2. The thermoplastic resin composition according to claim 1, wherein the ethylene / vinyl alcohol copolymer is an ethylene / vinyl alcohol copolymer having a vinyl alcohol content of 40 to 85 mol%. 3. The thermoplastic resin composition according to claim 1, wherein the polyamide is a polyamide or copolyamide having a melting point of 240 ° C. or lower. 4. The ionomer has a metal species selected from zinc, an alkali metal or an alkaline earth metal and has a neutralization degree of 1.
The thermoplastic resin composition according to claim 1, which is an ionomer of 0 to 90%. 5. An ethylene / vinyl alcohol copolymer 5
Heat obtained by melt-kneading 0 to 85 parts by weight, 10 to 40 parts by weight of an ionomer of an ethylene / unsaturated carboxylic acid copolymer having an unsaturated carboxylic acid content of 4 to 15 mol%, and 1 to 25 parts by weight of a polyamide. Plastic resin composition pellets. 6. A packaging material comprising at least one layer comprising the thermoplastic resin composition according to any one of claims 1 to 4. 7. The packaging material according to claim 6, comprising at least one olefin polymer layer.