WO1993001108A1

WO1993001108A1 - Food containers of nylon 6,6/6t

Info

Publication number: WO1993001108A1
Application number: PCT/CA1992/000263
Authority: WO
Inventors: Christian Leboeuf
Original assignee: Du Pont Canada Inc.
Priority date: 1991-07-09
Filing date: 1992-06-19
Publication date: 1993-01-21
Also published as: GB9114767D0; CA2113072A1

Abstract

A retortable moulded plastic food container, a food package made therefrom and a process for making the food package is disclosed. The container is made from a composition consisting essentially of: (a) a polymeric material selected from: (A) 80 to 100 wt.% of a polyamide which is a condensation product of adipic acid, terephthalic acid and hexamethylenediamine wherein the terephthalic acid is in an amount of from 45 to 100 mole % of the diacid content of the polyamide, (B) 80 to 100 wt.% of a polyamide which is a condensation product of terephthalic acid, isophthalic acid and hexamethylenediamine wherein the mole ratio of terephthalic acid to isophthalic acid is from 1:1 to 3:1, (C) 80 to 100 wt.% of a polyamide which is a condensation product of terephthalic acid, 2-methylpentamethylenediamine and hexamethylenediamine wherein the hexamethylenediamine is in an amount of from 25 to 75 mole % of the diamine content of the polyamide, and (D) 75 to 100 wt.% of blends of the polyamides of (A), (B) or (C) with nylon 6,6, wherein the nylon 6,6 has a relative viscosity of at least 40; and wherein the polyamides of (A), (B) and (C) have a heat of crystallization of from 20 to 50 J/g, as determined by differential scanning calorimetry; (b) from 0 to 20 wt.% of a lamellar filler, and (c) from 0 to 20 wt.% ionomer.

Description

FOOD CONTAINERS OF NYLON 6,6/6T Field of the Invention

The present invention relates to containers for prepared foods and in particular ovenable containers, e.g. a tray, and plastic-bodied food and beverage cans. Prior Art

Ovenable trays are used in the pre-packaged food industry. Usually food is placed on such trays, the trays are lidded and the lidded trays are placed in food refrigerators or freezers. It is known to sell foods, e.g. meals, in lidded trays, to consumers with the intention that the food in the lidded trays may be heated or cooked in a conventional, convection oven or a microwave oven. Such trays are often known in the trade as dual-ovenable trays. European Patent Publication No. 0 229 527 to D.L. inthrop, which was published 1987 July 22, discloses injection moulding of blends of nylon and a compatible olefin-based polymer to form dual-ovenable containers. Such dual-ovenable trays are covered with metallic foil, plastic film or rigid or semi-rigid lids. Food and beverage cans are containers which have at least one hermetically sealed metal end closure. It is known to package food and beverages in tin, steel, aluminium and plastic composite cans. The tin and steel cans have three hermetic seals. One is a longitudinal side seam in the body of the can and the others are seals formed by so-called double seams between the metal end closures and body of the can. An aluminium can may have the same three hermetic seals, but generally only has one by virtue of the fact that there is only one end closure because the body is formed to include an integral end. Plastic composite cans generally also only have one hermetic seal. The bodies of the plastic composite cans have heretofore generally been made from polypropylene sheet which has been coated with an oxygen barrier material or from a coextruded sheet of polypropylene and a barrier material. An example of such a coextruded sheet is polyvinylidene chloride or ethylene/vinyl alcohol sandwiched between layers of polypropylene. The plastic cans may be made by one of several thermoforming processes, for example a continuous melt thermoforming process. Thermoforming processes are known to be wasteful of materials and therefore tend to be relatively expensive.

It is also known to package foods and beverages in bottles, particularly glass or plastic bottles with screw cap lids.

For many food containers it is important to ensure that the containers are substantially impervious to gases, in particular oxygen. Substances which are substantially impervious to gases are known. For example it is known that polyamide films made from mixtures comprising certain aliphatic polyamides and certain aromatic polyamides have excellent oxygen barrier properties. In JP 53006355 to Toray Industries Inc., dated 1978 January 20 such mixtures are disclosed which contain 90-70 wt.% aromatic polyamides having >70 mole% terephthalic acid and isophthalic acid, and 10-30 wt.% aliphatic polyamides, e.g. nylon 6, nylon 6,6, nylon 12. Such mixtures are indicated as being used in high retort packing, gas barrier films, and packing of frozen foods.

JP 62041261 to Mitsubishi Chemical Industries KK, dated 1987 February 23 discloses biaxially drawn films, with good gas barrier properties, of polyamide resin compositions comprising mixtures of 10-40 wt.% aromatic and 90-60 wt.% aliphatic polyamides. The aromatic polyamide is obtained by polymerizing terephthalic acid and/or isophthalic acids and aliphatic diamines. The aliphatic polyamides may be nylon 6 or nylon 6,6. JP 62143969 to Mitsubishi Chemical Industries KK, dated 1987 June 27, discloses blown film, with high transparency and gas barrier properties, of polyamide resin compositions comprising a) 0-95 wt.% aliphatic polyamide and b) 100-5 wt.% of a mixture of i) 10-100 wt.% polyamide made from an aliphatic diamine, terephthalic acid and/or isophthalic acid, and ii) 90-0 wt.% polyamide made from an aliphatic diamine and an aliphatic dicarboxylic acid.

JP 62144948 to Mitsubishi Chemical Industries KK, dated 1987 June 27, discloses monoaxially or biaxially blowing a parison, with improved gas barrier properties (for carbonated beverages) , of i) a substrate layer of a polyamide resin compositions comprising a) 40-100 wt.% polyamide made from an aliphatic diamine, terephthalic acid and/or isophthalic acid, and b) 60-0 wt.% polyamide made from an aliphatic diamine and an aliphatic dicarboxylic acid, and ii) a layer of polyester resin. U.S. Patent 4 800 129 to G.I. Deak, dated 1989 January 24, discloses a thermoformed multilayer structure comprising at least first and second layers. The first layer comprises a blend of one or more amorphous polyamides having a glass transition temperature greater than 120°C and derived from one or more aliphatic diamines and one or more aromatic dicarboxylic acids with one or more semicrystalline aliphatic polyamides. The second layer comprises one or more structural thermoplastic resins. Preparation of the structure comprises casting or moulding a semi-finished multilayer shaped article of the first and second layers, followed by thermoforming the article at a temperature below 125°C. The multilayer structure is reported to have good optical and gas barrier properties. Specifically mentioned is a hexamethylenediamine iso/terephthalamide with a ratio of iso- to tere- phthala ide of 60/40 to 100/0. The semicrystalline polyamide may be nylon 6, nylon 6,6, nylon 6,10 and copolymers thereof. The structural resin may be polyethylene terephthalate, polyvinyl chloride, polyethylene, co- and ter- polymers of ethylene with vinyl acetate or ( eth)acrylic acid, and ionomers of these acids.

It is known to make moulded articles, e.g. automobile bumpers and fenders, from compositions of amorphous polyamides and semi-crystalline polyamides. For example, U.S. Patent 4 404 317 to Epstein et al., which issued 1983 September 13, discloses a blend of thermoplastic polyamide moulding resins comprising a) about 5 to 98 wt.% of a thermoplastic semi-crystalline polyamide of film-forming molecular weight and b) 95 to 2 wt.% of a thermoplastic amorphous copolyamide consisting essentially of i) 40 to 98 mole % units of isophthalic acid based on the total acids present, ii) 2 to 60 mole % units of terephthalic acid based on the total acids present, iii) 50 to 98 mole % of units of hexamethylene diamine based on total amines present and iv) 2 to 50 mole % of at least one aliphatic diamine containing between 8 and 20 carbon atoms and containing at least one cyclohexane oeity, based on the total amines present. Examples of the semi-crystalline polyamide include nylon 6, nylon 6,6, nylon 69, nylon 6,10 and nylon 6,12. Representative aliphatic dia ines include l-amino-3-aminomethyl3,5,5-trimethylcyclohexane, 1,4-bis(aminomethyl)cyclohexane and bis(p-aminocyclohexane)methane. The compositions may contain additives, fillers and the like, such as glass, mica, dyes, heat stabilizers, antioxidants , plasticizers and UV stabilizers.

Canadian Patent 1 181 191 to Epstein et al., which issued 1985 January 15, discloses blends of thermoplastic polyamide moulding resins containing I) 99 to 60 wt.% of thermoplastic polyamides comprising a) about 20 to 90 wt.%, based on total polyamide, of a thermoplastic semi-crystalline polyamide of film-forming molecular weight and b) 80 to 10 wt.%, based on total polyamide, of at least one thermoplastic amorphous copolyamide obtained from at least one aromatic dicarboxylic acid containing 8 to 18 carbon atoms and at least one diamine selected from the class consisting of i) 2 to 12 carbon normal aliphatic straight chained diamine, ii) 4 to 18 carbon branched aliphatic diamine and iii) 8 to 20 carbon cycloaliphatic diamine containing at least one cycloaliphatic moeity and wherein optionally, up to 50 wt.% of the amorphous polyamide may consist of units obtained from lactams or omega-aminoacids containing 4 to 12 carbon atoms, or from polymerization salts of aliphatic dicarboxylic acids containing 4 to 12 carbon atoms and aliphatic diamines containing 4 to 12 carbon atoms, with complementally II) 1 to 40 wt.% of a blend of a toughening agent having a maximum tensile modulus of 80 000 psi, that is an organic polymer of film forming molecular weight which imparts to component a) a notched Izod value of at least 50% greater than the notched Izod value of component a) alone when 20 wt.% of the toughening agent is present with component a) . U.S. Patent 4 937 276 to Nielinger at al, dated 1990 June 26 discloses an improved moulding composition of a) a polyamide containing the condensation product of adipic acid, terephthalic acid and hexamethylenediamine, b) glass fibres and c) a mixture of copper-, halogen- and phosphorus-containing stabilizers for articles such as radiator tanks for the automotive industry. Detailed Description of the Invention

There is a need for food containers to be made from a single composition in order to make manufacture easier and to permit recycling of used containers. None of the aforementioned references provide any teachings in this regard. The present invention attempts to provide food containers meeting such criteria.

Accordingly the present invention provides a retortable moulded plastic food container, said container being made from a composition consisting essentially of: a) a polymeric material selected from:

A) 80 to 100 wt.% of a polyamide which is a condensation product of adipic acid, terephthalic acid and hexamethylenediamine wherein the terephthalic acid is in an amount of from 45 to 100 mole% of the diacid content of the polyamide,

B) 80 to 100 wt.% of a polyamide which is a condensation product of terephthalic acid, isophthalic acid and hexamethylenediamine wherein the mole ratio of terephthalic acid to isophthalic acid is from 1:1 to 3:1,

C) 80 to 100 wt.% of a polyamide which is a condensation product of terephthalic acid, 2- methylpentamethylene diamine and hexamethylenediamine wherein the hexamethylenediamine is in an amount of from 25 to 75 mole% of the diamine content of the polyamide, and

D) 75 to 100 wt.% of blends of the polyamides of A), B) or C) with nylon 6,6, wherein the nylon 6,6 has a relative viscosity of at least 40; and wherein the polyamides of A) , B) and C) have a heat of crystallization of from 20 to 50 J/g, as determined by differential scanning calorimetry; b) from 0 to 20 wt.% of a lamellar filler, and c) from 0 to 20 wt.% ionomer.

In one embodiment the filler is mica. In a preferred embodiment the container has a wall thickness of from 0.3 to 1.2 mm.

The invention also provides a shelf stable food package consisting of food or beverage contained in a plastic-bodied container comprising an injection moulded or injection blow moulded body, having one or two open ends, each open end having an end closure hermetically sealed thereto, said body being made from a composition consisting essentially of: a) a polymeric material selected from:

A) 80 to 100 wt.% of a polyamide which is a condensation product of adipic acid, terephthalic acid and hexamethylenediamine wherein the terephthalic acid is in an amount of from 45 to 100 mole% of the diacid content of the polyamide, B) 80 to 100 wt.% of a polyamide which is a condensation product of terephthalic acid, isophthalic acid and hexamethylenediamine wherein the mole ratio of terephthalic acid to isophthalic acid is from 1:1 to 3:1, C) 80 to 100 wt.% of a polyamide which is a condensation product of terephthalic acid, 2- methylpentamethylene diamine and hexamethylenediamine wherein the hexamethylenediamine is in an amount of from 25 to 75 mole% of the diamine content of the polyamide, and

In another aspect of the invention food or beverage is packaged and prepared in a hermetically sealed plastic-bodied container by : i) placing the food or beverage in a plastic-bodied container, said container having walls and a bottom joined to said walls; and ii) lidding the plastic-bodied container with an end closure such that the seal between the container and the end closure is hermetic, to form a shelf stable, food or beverage package; said plastic-bodied container being injection moulded or injection blow moulded and made from a composition consisting essentially of: a) a polymeric material selected from:

Preferably the lamellar filler is mica. In a preferred embodiment the container has a wall thickness of from 0.3 to 1.2 mm. Particularly preferred copolyamides have intrinsic viscosities (IV) in the range of 0.85 to 1.40 dl/g. It is preferred that the intrinsic viscosity be in the range of 0.90 to 1.10 dl/g, particularly 0.95 to 1.10 dl/g. Intrinsic viscosity is measured at 250C in concentrated sulphuric acid (at least 96.2 wt.% acid in water) or m-cresol by methods known in the art.

A preferred ionomer is a partially neutralized ethylene/methacrylic copolymer. Sodium ionomers are preferred.

The composition may contain a small amounts of modifying materials selected from the group consisting of pigments, dyes, small quantities of antioxidants, thermal stabilizers, lubricants, release agents, flow modifiers and the like and mixtures thereof, as is known in the art. The specific modifying material chosen will depend on the end-use requirements. The lamellar filler should preferably have a largest dimension (hereinafter referred to as ^■■diameter") of less than about 150 μm and a minimum particle diameter to particle thickness ratio (otherwise referred to as the aspect ratio) of about 20:1. It is preferable that the aspect ratio be as large as practical, e.g. as large as 50:1 to 100:1. Wet ground mica is the preferred filler, having a particle size between 150 μm and 5μm) , particularly between 100 μm and 25μm. Suitable grades of mica are sold under the trade marks WG-325, from Dempsey & Co., and Huber Aspraflex 100. The fillers may be added in amounts of up to 20 wt.% of the blend, preferably in amounts of 10 to 20 wt.%.

In addition, pigments or dyes may be added for aesthetic effect. In particular, titanium dioxide may be added for whiteness. Other pigments may be added for their colour appeal. Antioxidant, e.g. 1,3,5-trimethyl-2,4,6-tris(3,5-di-tertbutyl-4-hydroxy- benzyl)benzene, heat stabilizers, e.g. a phenolic antioxidant, processing aids and the like may also be added as are known in the art. As is apparent to those skilled in the art, only those additives which are approved for food contact at elevated temperatures would be selected. The container has a shaped lip at each open end of the container, the purpose of which is to provide a means for attaching an end closure or lid to the container. For packages intended for retorting, most preferably the end closure is of metal, usually of the screw top-type or of the can closure-type. As will be apparent the shaped lip will need to have a screw thread if the lid is to be a screw top. The lip will have a shape and thickness suitable for bending into a so-called body hook if the lid is to be attached in a double seaming can lidding process. Attachment of the metal lids is by mechanical means known in the art, e.g. the can closure type may be attached by a double seaming process.

In the case of can-type containers it is preferred that the containers be nestable for ease of transportation of the unfilled containers. The walls are most often relatively long compared to a cross sectional dimension of the bottom of the container.

With respect to packaging of food in a can-type container, the container is filled with the foodstuff and subsequently lidded with a hermetically sealed end closure, preferably with a high speed double seaming can lidding process as is known in the art. The food package so formed is then retorted in an oven, the temperature and time of retorting being dependent on the amount and type of food present in the lidded container. Typically the food package is retorted for 30-60 min. at temperatures of about 115"C to 150"C. The package is then cooled in a known manner and readied for shipping to customers.

If the container is intended for the packaging of refrigerated or frozen foods, in which the food is generally placed in trays, e.g. dual-ovenable trays, the container may have a peripheral shaped lip, the purpose of which is to provide a means for attaching a lid to the container and/or stiffen the container. Attachment of the lid may be by mechanical means, e.g. by crimping, or by other means, e.g. adhesive attachment. The peripheral shaped lip, if present, may be thicker than other parts of the container. The shape of the lip may be any one of known forms. The container may also be compartmentalized in order to separate different kinds of food, for example in a two-compartment tray, meat may be in one compartment and vegetables in another. The compartments may be formed in such a way that each compartment is, in itself, a container and adjacent compartments are joined only at the lip of the walls of the containers. The latter construction of the container is more expensive to produce because, in essence, there are two walls between adjacent compartments rather than one, as in the former construction.

Dual-ovenable containers are preferably tray shaped, i.e. with relatively shallow walls compared to the surface area of the floor of the container.

The container may be injection moulded or injection blow moulded by known methods. With injection moulding the whole of the plastic portion of the container is moulded using an injection moulding machine. With injection blow moulding the "neck" portion of the container is injection moulded and the remainder of the container is blow moulded in a second moulding step with a blow moulding machine. The selection of thickness of the container depends in part upon the size of the container and in part upon the composition of the material from which the container is to be injection moulded and the degree of shelf stability required. Merely from a structural standpoint, it will be clear, that, for a given composition and container design, the thicker the container the stiffer and tougher will be the container. It will also be appreciated, however, that the thicker the container, the heavier and more costly to produce it will be. Injection moulding is preferred because it is believed to be beneficial in orienting the lamellar filler particles parallel to the polymer flow.

In use, a preferred embodiment is one in which the walls and bottom of the container are injection moulded integrally.

A particular advantage of the container of the present invention is that there is little waste formed in the injection moulding or injection blow moulding process. Additionally, in the case where the plastic is homogeneous, e.g. without coating layers, if there is a need to recycle any defective containers the fact that the plastic is homogeneous allows it to be remoulded or ground up and blended in with virgin material and moulded into new containers.

Although the above description is particularly directed to retorted foods and dual-ovenable trays, the container of the present invention may also be used for beverages, e.g. soft drinks.

The present invention may be illustrated by the following examples: EXAMPLE I Compositions, as indicated below, were injection moulded into single portion "snack tub" containers, each having a bottom 7.3 cm in diameter, an open top 9.9 cm in diameter and walls 8.1 cm high with an average wall thickness of 0.88 mm. Containers were tested, in triplicate, for moisture and oxygen permeation rates. Furthermore, container performance was evaluated for double-seaming, with standard "307" aluminium lids, on conventional canning equipment, for retortability in a steam/air retort autoclave, and for impact resistance after retort. Retorting was done, with water in the container, at 121"C for 60 min with an overpressure of 207 kPa.

After cooling to room temperature, impact resistance was measured by allowing the retorted container to slide down a ramp, inclined at 15". The vertical height of the slide was 122 cm and the container was positioned such that the seam between the lid and container hit a concrete floor after leaving the ramp. The container and lid were inspected after impact.

Oxygen permeation was measured using the method of ASTM D-3985-81. Moisture permeation was determined gravimetrically by measuring weight loss from filled, double-seamed and retorted containers, using a temperature and humidity controlled chamber to create the desired ambient conditions. Composition H consisted of 88.6 wt.% of a copolyamide of terephthalic acid, adipic acid and hexamethylenediamine, 10 wt.% Aspraflex 100 mica, 1.0 wt.% titanium dioxide pigment and 0.4 wt.% zinc stearate. The terephthalic acid was 50 mole% of the acid content of the polymer. Aspraflex 100 mica is wet ground and has an particle size range of about 5 to lOOμm. Prior to moulding the copolyamide had an intrinsic viscosity of 0.98. After moulding the copolyamide had an intrinsic viscosity of 0.845. Composition I consisted of 88.6 wt.% of a copolyamide of terephthalic acid, adipic acid and hexamethylenediamine, 10 wt.% Aspraflex 100 mica, 1.0 wt.% titanium dioxide pigment and 0.4 wt.% zinc stearate. The terephthalic acid was 50 mole% of the acid content of the polymer. Prior to moulding the copolyamide had an intrinsic viscosity of 0.95. The containers were moulded from a "salt and pepper" blend of pellets of a) a mica masterbatch of 18.5 wt.% mica in a terephthalic acid, adipic acid, hexamethylenediamine copolyamide having an intrinsic viscosity of 0.86 and b) 91.5 wt.% of a terephthalic acid, adipic acid, hexamethylenediamine copolyamide having an intrinsic viscosity of 1.06. After moulding the copolyamide had an intrinsic viscosity of 0.89. The results of the testing on the containers made from Compositions H and I are shown in Table I below: TABLE I

Composition Water Transmission Oxygen Transmission*

H 0.014 0.016

0.009 0.006

¹Water transmission is in % water loss/package.day.atmos. , measured at 38°C and 50% relative humidity.

⁴Oxygen transmission is in ml Oi/package.day.atmos. , measured at 23.7°C and 100% relative humidity inside and outside the package, and 100% Nj, inside and 100% 0* outside the package. EXAMPLE II

Containers similar to those in Example I were produced from Compositions E, F and I. Composition I was as identified in Example I. Composition E consisted of 100% of a copolyamide of terephthalic acid, adipic acid and hexamethylenediamine, wherein the terephthalic acid content was 50 mole% of the acid content of the polymer. Composition F consisted of a condensation product of terephthalic acid, 2- methylpentamethylenediamine and hexamethylenediamine, wherein the hexamethylenediamine content was 50 mole% of the diamine content of the polymer.

Such containers were tested for moisture transmission and the results are shown in Table II below.

TABLE II

loss/package.day.atmos. , measured at 20^βC and 50% relative humidity.

*Water transmission is in % water loss/package.day.atmos. , measured at 20"C and 20% relative humidity.

COMPARATIVE EXAMPLE III

Containers similar to those in Example I were produced from several compositions, all of which fall outside the scope of the present invention. Composition A consisted of 90 wt.% of a copolymer of terephthalic acid, adipic acid and hexamethylenediamine, and 10 wt.% Aspraflex 100 mica.

The terephthalic acid was 35 mole% of the acid content of the polymer. Prior to moulding the copolyamide had an intrinsic viscosity of 0.98.

Composition B consisted of 82.9 wt.% of a nylon 6,6, 15 wt.% Aspraflex 100 mica, 1.8 wt.% titanium dioxide pigment and 0.3 wt.% zinc stearate.

Composition C consisted of 29 wt.% of a nylon 6,6, 70 wt.% of an amorphous copolymer of terephthalic acid, isophthalic acid and hexamethylenediamine, and 1 wt.% titanium dioxide pigment. The terephthalic acid was 30 mole% of the acid content of the polymer.

Composition D consisted of 24.9 wt.% of a nylon 6,6, 58 wt.% of an amorphous copolymer of terephthalic acid, isophthalic acid and hexamethylenediamine, 15 wt.% of a copolymer of ethylene and methacrylic acid, partially neutralized with sodium ions, and 1.8 wt.% titanium dioxide pigment and 0.3 wt.% zinc stearate. The terephthalic acid was 30 mole% of the acid content of the polymer.

Compositions C and D are within the scope of

U.S.Patent 4 404 317 to Epstein et al. Compositions A to D are included for comparison purposes only. Such containers were also tested as indicated in

Example I. The results are shown in Table III below. TABLE III

Water transmission s n % water loss/package.day.atmos. , measured at 38^βC and 50% relative humidity. ⁴Oxygen transmission is in ml

Oi/package.day.atmos. , measured at 23.7^βC and 100% relative humidity inside and outside the package, and 100% Na. inside and 100% Oi outside the package.

Claims

CLAIMS:

1. A retortable moulded plastic food container, said container being made from a composition consisting essentially of: a) a polymeric material selected from:

2. A food container according to Claim 1 wherein the lamellar filler is mica.

3. A food container according to Claim 1 wherein the container has a wall thickness of from 0.3 to 1.2 mm.

4. A food container according to Claim 1 wherein the copolyamides have intrinsic viscosities (IV) in the range of 0.85 to 1.40 dl/g. It is preferred that the intrinsic viscosity be in the range of 0.90 to 1.10 dl/g, particularly 0.95 to 1.10 dl/g.

5. A food container according to Claim 1 wherein the ionomer is a partially neutralized ethylene/methacrylic copolymer.

6. A shelf stable food package consisting of food or beverage contained in a plastic-bodied container comprising an injection moulded or injection blow moulded body, having one or two open ends, each open end having an end closure hermetically sealed thereto, said body being made from a composition consisting essentially of: a) a polymeric material selected from:

C) 80 to 100 wt.% of a polyamide which is a condensation product of terephthalic acid, 2- methylpentamethylene diamine and hexamethylenediamine wherein the hexamethylenediamine is in an amount of from 25 to 75 mole% of the diamine content of the polyamide, and D) 75 to 100 wt.% of blends of the polyamides of A), B) or C) with nylon 6,6, wherein the nylon 6,6 has a relative viscosity of at least 40; and wherein the polyamides of A) , B) and C) have a heat of crystallization of from 20 to 50 J/g, as determined by differential scanning calorimetry; b) from 0 to 20 wt.% of a lamellar filler, and c) from 0 to 20 wt.% ionomer.

7. A food package according to Claim 6 wherein the lamellar filler is mica.

8. A food package according to Claim 6 wherein the container has a wall thickness of from 0.3 to 1.2 mm.

9. A food package according to Claim 6 wherein the copolyamides have intrinsic viscosities (IV) in the range of 0.85 to 1.40 dl/g. It is preferred that the intrinsic viscosity be in the range of 0.90 to 1.10 dl/g, particularly 0.95 to 1.10 dl/g.

10. A food package according to Claim 6 wherein the ionomer is a partially neutralized ethylene/methacrylic copolymer.

11. A process for packaging a food or beverage in a hermetically sealed plastic-bodied container by : i) placing the food or beverage in a plastic-bodied container, said container having walls and a bottom joined to said walls; and ii) lidding the plastic-bodied container with an end closure such that the seal between the container and the end closure is hermetic, to form a shelf stable, food or beverage package; said plastic-bodied container being injection moulded or injection blow moulded and made from a composition consisting essentially of: a) a polymeric material selected from: A) 80 to 100 wt.% of a polyamide which is a condensation product of adipic acid, terephthalic acid and hexamethylenediamine wherein the terephthalic acid is in an amount of from 45 to 100 mole% of the diacid content of the polyamide, B) 80 to 100 wt.% of a polyamide which is a condensation product of terephthalic acid, isophthalic acid and hexamethylenediamine wherein the mole ratio of terephthalic acid to isophthalic acid is from 1:1 to

3:1, C) 80 to 100 wt.% of a polyamide which is a condensation product of terephthalic acid, 2- methylpentamethylene diamine and hexamethylenediamine wherein the hexamethylenediamine is in an amount of from 25 to 75 mole% of the diamine content of the polyamide, and

D) 75 to 100 wt.% of blends of the polyamides of A) , B) or C) with nylon 6,6, wherein the nylon 6,6 has a relative viscosity of at least 40; and wherein the polyamides of A) , B) and C) have a heat of crystallization of from 20 to 50 J/g, as determined by differential scanning calorimetry; b) from 0 to 20 wt.% of a lamellar filler, and c) from 0 to 20 wt.% ionomer.

12. A process according to Claim 11 wherein the lamellar filler is mica.

13. A process according to Claim 11 wherein the container has a wall thickness of from 0.3 to 1.2 mm.

14. A process according to Claim 11 wherein the copolyamides have intrinsic viscosities (IV) in the range of 0.85 to 1.40 dl/g. It is preferred that the intrinsic viscosity be in the range of 0.90 to 1.10 dl/g, particularly 0.95 to 1.10 dl/g.

15. A process according to Claim 11 wherein the ionomer is a partially neutralized ethylene/methacrylic copolymer.