PHA-based cooked food bag

Abstract

A cooked food pouch is disclosed comprising at least one side wall and a pouch closure. The side wall is of a multi-layer structure and is made of the following parts: (1) a biodegradable heat-sealable layer comprising polyhydroxyalkanoate; (2) a barrier layer comprising aluminum and / or polyhydroxyalkanoate; (3) an optional nylon layer; and (4) a biodegradable printed layer, which also comprises a polyhydroxyalkanoate and / or cellulose. The layers are bonded together by one or more adhesives to form a multilayer structure.

Description

Technical Field

[0001] The present disclosure relates to biodegradable polymer compositions. More particularly, the present disclosure relates to a retort food pouch formed from a multi-layer structure including a biodegradable and / or home compostable layer. Background Art

[0002] In food packaging, retorting is a method of cooking and preserving food at a higher temperature and then vacuum sealing it in a bag-like food packaging for later consumption. This method extends the shelf life of food and allows food to be sold as "ready-to-eat", where the food can be eaten directly or reheated. Retorting is preferred over canning because retorting packaging is lighter, easier to transport, and less energy is consumed during preparation. Common foods prepared by retorting include meat, soup, rice, and curry, and the most common example of retorting packaging is MRE (Meal Ready to Eat), which is most commonly used in the military.

[0003] Retort packaging must be able to heat seal and heat to high temperatures (approximately 120°C) while providing barrier properties to water and oxygen. For commercial applications, retort packaging must also be printable for marketing purposes. These performance requirements are met by using multiple layers of materials, each serving a specific purpose. Typically, these materials include polypropylene, nylon, polyethylene terephthalate, polyethylene, and aluminum. However, the plastics used are petroleum-based and are not a sustainable choice. In addition, recycling these packages is difficult because the different materials will be difficult to separate and may contaminate separate recycling streams if recycled together.

[0004] There is a need to provide a multilayer food packaging structure suitable for preparing a retort food package, wherein at least some of the individual layers of the multilayer structure are biodegradable and / or compostable. Preferably, the entire retort food package will be biodegradable and / or compostable. Summary of the invention

[0005] The retort food bag provided by the present disclosure meets the above and other needs. According to one embodiment, the retort food bag includes at least one side wall and a bag seal. The at least one side wall is a multilayer structure made of: (1) a biodegradable heat-sealable layer, the heat-sealable layer includes polyhydroxyalkanoate; (2) a barrier layer, the barrier layer includes aluminum and / or polyhydroxyalkanoate; (3) optionally, a nylon layer; and (4) a biodegradable print layer, the print layer also includes polyhydroxyalkanoate and / or cellulose. The layers are bonded together by one or more adhesives to form a multilayer structure.

[0006] In certain embodiments, the biodegradable heat-sealable layer preferably comprises: (1) about 10 wt % to about 99 wt % of a polyhydroxyalkanoate; (2) about 1 wt % to 90 wt % of at least one biodegradable polymer selected from the group consisting of polybutylene succinate, polycaprolactone, polybutylene succinate-adipate, polybutylene adipate-terephthalate, polylactic acid, cellulose acetate, and mixtures thereof; (3) about 0.1 wt % to about 5 wt % of at least one nucleating agent, the nucleating agent (4) optionally, about 1 wt % to about 25 wt % of at least one filler selected from the group consisting of clay, calcium carbonate, talc, kaolinite, montmorillonite, bentonite, silica, chitin, titanium dioxide, nanoclay, and mixtures thereof.

[0007] In some embodiments, the polyhydroxyalkanoate in the biodegradable heat-sealable layer more preferably includes poly(3-hydroxybutyrate-3-hydroxyhexanoate) (P3HB-co-P3HHx).

[0008] In some cases, the biodegradable heat-sealable layer more preferably includes about 1.0 wt % to about 15.0 wt % of at least one polyhydroxyalkanoate, wherein the polyhydroxyalkanoate contains about 25 mol % to about 50 mol % of 3-hydroxyalkanoate monomer residues, and the 3-hydroxyalkanoate is selected from the group consisting of 3-hydroxyvalerate, 3-hydroxyhexanoate, 3-hydroxyoctanoate, 3-hydroxydecanoate and mixtures thereof.

[0009] According to some embodiments, the biodegradable heat-sealable layer more preferably includes a polyhydroxyalkanoate terpolymer, which is made of about 75 mol% to about 99.9 mol% of 3-hydroxybutyrate monomer residues, about 0.1 mol% to about 25 mol% of 3-hydroxyhexanoate monomer residues and about 0.1 mol% to about 25 mol% of a third 3-hydroxy fatty acid ester monomer residue, and the third 3-hydroxy fatty acid ester is selected from the group consisting of 3-hydroxyvalerate, 3-hydroxyoctanoate, 3-hydroxydecanoate and mixtures thereof.

[0010] In certain embodiments, the biodegradable heat-sealable layer preferably comprises a polyhydroxyalkanoate having a weight average molecular weight of about 50,000 Daltons to about 2,500,000 Daltons (as measured in accordance with ASTM D5296-05).

[0011] According to certain embodiments, the barrier layer preferably comprises: (1) about 10 wt % to about 99 wt % of a polyhydroxyalkanoate; (2) about 1 wt % to 90 wt % of at least one biodegradable polymer, wherein the at least one biodegradable polymer is selected from the group consisting of polybutylene succinate, polycaprolactone, polybutylene succinate-adipate, polybutylene adipate-terephthalate, polylactic acid, cellulose acetate, and mixtures thereof; (3) about 0.1 wt % to about 5 wt % of at least one nucleating agent, wherein the nucleating agent (4) optionally, about 1 wt % to about 25 wt % of at least one filler selected from the group consisting of clay, calcium carbonate, talc, kaolinite, montmorillonite, bentonite, silica, chitin, titanium dioxide, nanoclay, and mixtures thereof.

[0012] In some cases, the polyhydroxyalkanoate in the barrier layer is preferably made of poly(3-hydroxybutyrate-3-hydroxyhexanoate) (P3HB-co-P3HHx).

[0013] In some embodiments, the barrier layer preferably includes about 1.0 wt % to about 15.0 wt % of at least one polyhydroxyalkanoate, wherein the at least one polyhydroxyalkanoate contains about 25 mol % to about 50 mol % of 3-hydroxyalkanoate monomer residues, and the 3-hydroxyalkanoate is selected from the group consisting of 3-hydroxyvalerate, 3-hydroxyhexanoate, 3-hydroxyoctanoate, 3-hydroxydecanoate and mixtures thereof.

[0014] In other embodiments, the barrier layer preferably includes a polyhydroxyalkanoate terpolymer, wherein the polyhydroxyalkanoate terpolymer is made of about 75 mol% to about 99.9 mol% 3-hydroxybutyrate monomer residues, about 0.1 mol% to about 25 mol% 3-hydroxyhexanoate monomer residues and about 0.1 mol% to about 25 mol% of a third 3-hydroxy fatty acid ester monomer residue, wherein the third 3-hydroxy fatty acid ester is selected from the group consisting of 3-hydroxyvalerate, 3-hydroxyoctanoate, 3-hydroxydecanoate and mixtures thereof.

[0015] According to certain embodiments, the barrier layer preferably comprises a polyhydroxyalkanoate having a weight average molecular weight of about 50,000 Daltons to about 2,500,000 Daltons (determined according to ASTM D5296-05).

[0016] In some cases, it is preferred that the barrier layer include aluminum.

[0017] In some embodiments, the multilayer structure preferably has a total thickness of about 25 microns to about 75 microns. The aluminum barrier layer preferably has a thickness of about 3 microns to about 13 microns. When the optional biaxially oriented nylon layer is present, the nylon layer preferably has a thickness of about 5 microns to about 15 microns.

[0018] According to some embodiments, the biodegradable printing layer preferably includes: (1) about 10 wt % to about 99 wt % of polyhydroxyalkanoate; (2) about 1 wt % to 90 wt % of at least one biodegradable polymer, wherein the at least one biodegradable polymer is selected from the group consisting of polybutylene succinate, polycaprolactone, polybutylene succinate-adipate, polybutylene adipate-terephthalate, polylactic acid, cellulose acetate, and mixtures thereof; (3) about 0.1 wt % to about 5 wt % of at least one nucleating agent, wherein the at least one biodegradable polymer is selected from the group consisting of polybutylene succinate, polycaprolactone, polybutylene succinate-adipate, polybutylene adipate-terephthalate, polylactic acid, cellulose acetate, and mixtures thereof. The nucleating agent is selected from the group consisting of erythritol, pentaerythritol, dipentaerythritol, artificial sweeteners, stearate, sorbitol, mannitol, inositol, polyester wax, nanoclay, behenamide, erucamide, stearamide, oleamide, polyhydroxybutyrate, boronitride and mixtures thereof; and (4) optionally, about 1 wt % to about 25 wt % of at least one filler selected from the group consisting of clay, calcium carbonate, talc, kaolinite, montmorillonite, bentonite, silica, chitin, titanium dioxide, nanoclay and mixtures thereof.

[0019] According to certain embodiments, the biodegradable printing layer is preferably made of a core sublayer and at least one skin sublayer.

[0020] In some cases, the polyhydroxyalkanoate in the biodegradable printing layer more preferably includes poly(3-hydroxybutyrate-3-hydroxyhexanoate) (P3HB-co-P3HHx).

[0021] In some cases, the biodegradable printing layer more preferably includes about 1.0 wt % to about 15.0 wt % of at least one polyhydroxyalkanoate, wherein the at least one polyhydroxyalkanoate contains about 25 mol % to about 50 mol % of 3-hydroxyalkanoate monomer residues, wherein the 3-hydroxyalkanoate is selected from the group consisting of 3-hydroxyvalerate, 3-hydroxyhexanoate, 3-hydroxyoctanoate, 3-hydroxydecanoate and mixtures thereof.

[0022] According to certain embodiments, the biodegradable printing layer more preferably includes a polyhydroxyalkanoate terpolymer, wherein the polyhydroxyalkanoate terpolymer is made of about 75 mol% to about 99.9 mol% of 3-hydroxybutyrate monomer residues, about 0.1 mol% to about 25 mol% of 3-hydroxyhexanoate monomer residues, and about 0.1 mol% to about 25 mol% of a third 3-hydroxy fatty acid ester monomer residue, wherein the third 3-hydroxy fatty acid ester is selected from the group consisting of 3-hydroxyvalerate, 3-hydroxyoctanoate, 3-hydroxydecanoate and mixtures thereof.

[0023] In some embodiments, the biodegradable print layer preferably includes a polyhydroxyalkanoate having a weight average molecular weight of about 50,000 Daltons to about 2,500,000 Daltons (determined according to ASTM D5296-05).

[0024] Alternatively, according to some embodiments, the printing layer may be made of a biodegradable cellulose-based material.

[0025] In some cases, the biodegradable print layer preferably has a thickness of about 5 microns to about 25 microns.

[0026] According to certain embodiments, the biodegradable printed layer is preferably printed using flexographic printing, gravure printing or digital printing methods.

[0027] In some embodiments, the layers of the multilayer structure are preferably bonded together by at least one adhesive comprising at least one polymer selected from the group consisting of polycaprolactone, isocyanate, polyurethane, polybutylene succinate-adipate, polybutylene adipate-terephthalate, polyhydroxyalkanoates, polylactic acid, and mixtures thereof.

[0028] In certain embodiments, all layers of the multilayer structure preferably have a melting point greater than 120° C. (measured according to ASTM E794-06).

[0029] In some embodiments, the retort pouch has a shelf life of at least 18 months (as measured according to ASTM E2454).

[0030] According to certain preferred embodiments, the multilayer structure has a volume fraction of less than 0.45 ml / m 2 / 24h oxygen transmission rate (determined according to ASTM D3985). Further, the multilayer structure also preferably has an oxygen transmission rate of less than 0.2 g / m 2 / 24h water vapor transmission rate (measured according to ASTM F1249). DETAILED DESCRIPTION

[0031] As used herein, the term "biodegradable" refers to a plastic or polymeric material that is biodegraded by living organisms (microorganisms) in an anaerobic or aerobic environment as determined by ASTM D5511 (anaerobic) and D5338 (aerobic).

[0032] As used herein, the term "compostable" refers to a plastic or polymeric material that biodegrades in a home composting environment as determined by ASTM D6868.

[0033] In a first aspect, the present disclosure provides a retort food bag. The retort food bag includes at least one side wall and a bag seal. A roll of a multilayer film structure is first formed into a series of retort food bags. Each bag is formed by folding and heat-sealing a length of the multilayer film structure along the bottom and sides of the bag. This forms a common bag shape with a top opening.

[0034] The top of the bag is then opened and the bag is filled with food. In some cases, solid food and liquid food can be added to the retort bag at different food filling stations. The interior of the retort bag can also be flushed with nitrogen to provide a low oxygen environment within the bag, thereby increasing the storage time of the food.

[0035] The top of the filled bag is then heat sealed and the filled and sealed bag can be heated to cook and sterilize the bag and its food contents.

[0036] Accordingly, the side wall of the retort bag is provided as a multilayer film structure. The multilayer structure generally includes at least (1) a biodegradable heat-sealable layer, the biodegradable heat-sealable layer comprising polyhydroxyalkanoate; (2) a barrier layer comprising aluminum and / or polyhydroxyalkanoate; and (3) a biodegradable print layer, the biodegradable print layer also comprising polyhydroxyalkanoate and / or cellulose. In some cases, the multilayer structure may also include a nylon film layer. Therefore, in such an embodiment, the multilayer structure is made of: (1) a biodegradable heat-sealable layer, the biodegradable heat-sealable layer comprising polyhydroxyalkanoate; (2) a barrier layer comprising aluminum and / or polyhydroxyalkanoate; (3) a nylon layer; and (4) a biodegradable print layer, the biodegradable print layer also comprising polyhydroxyalkanoate and / or cellulose.

[0037] Generally speaking, the multilayer structure preferably has a total thickness of about 25 microns to about 75 microns.

[0038] As mentioned above, the first layer of the multilayer structure is a biodegradable heat sealable layer, and the biodegradable heat sealable layer comprises at least one form of polyhydroxyalkanoate. In some cases, the polyhydroxyalkanoate of the heat sealable layer can be a homopolymer. However, more typically, the polyhydroxyalkanoate of the heat sealable layer comprises a polyhydroxyalkanoate copolymer or a terpolymer.

[0039] For example, in certain embodiments, the biodegradable heat-sealable layer may include a polyhydroxyalkanoate copolymer, such as poly(3-hydroxybutyrate-3-hydroxyhexanoate) (P3HB-co-P3HHx).

[0040] Generally, the biodegradable heat-sealable layer may comprise from about 1.0 wt % to about 15.0 wt % of at least one polyhydroxyalkanoate, wherein the at least one polyhydroxyalkanoate comprises from about 25 mol % to about 50 mol % of 3-hydroxyalkanoate monomer residues, wherein the 3-hydroxyalkanoate is selected from the group consisting of 3-hydroxyvalerate, 3-hydroxyhexanoate, 3-hydroxyoctanoate, 3-hydroxydecanoate and mixtures thereof.

[0041] In other embodiments, the biodegradable heat-sealable layer may comprise a polyhydroxyalkanoate terpolymer made from about 75 mol % to about 99.9 mol % of 3-hydroxybutyrate monomer residues, about 0.1 mol % to about 25 mol % of 3-hydroxyhexanoate monomer residues, and about 0.1 mol % to about 25 mol % of a third 3-hydroxy fatty acid ester monomer residue, wherein the third 3-hydroxy fatty acid ester is selected from the group consisting of 3-hydroxyvalerate, 3-hydroxyoctanoate, 3-hydroxydecanoate, and mixtures thereof.

[0042] Typically, the polyhydroxyalkanoate in the biodegradable heat-sealable layer has a weight average molecular weight of about 50,000 Daltons to about 2,500,000 Daltons (determined according to ASTM D5296-05).

[0043] Generally, the amount of polyhydroxyalkanoate in the biodegradable heat-sealable layer is from about 10 wt % to about 99 wt % of the heat-sealable layer.

[0044] In some cases, the heat sealable layer may further comprise about 1 wt % to 90 wt % of at least one additional biodegradable polymer. Such additional biodegradable polymer is preferably selected from the group consisting of polybutylene succinate, polycaprolactone, polybutylene succinate-adipate, polybutylene adipate-terephthalate, polylactic acid, cellulose acetate and mixtures thereof.

[0045] The heat sealable layer generally further comprises a nucleating agent. Preferably, the heat sealable layer comprises about 0.1 wt % to about 5 wt % of at least one nucleating agent selected from the group consisting of erythritol, pentaerythritol, dipentaerythritol, artificial sweeteners, stearic acid, sorbitol, mannitol, inositol, polyester wax, nanoclay, behenamide, erucamide, stearamide, oleamide, polyhydroxybutyrate, boronitride, and mixtures thereof.

[0046] In some cases, the heat sealable layer may further include about 1 wt % to about 25 wt % of at least one filler selected from the group consisting of clay, calcium carbonate, talc, kaolinite, montmorillonite, bentonite, silica, chitin, titanium dioxide, nanoclay, and mixtures thereof. A particularly preferred filler is talc.

[0047] The multilayer structure further comprises a barrier layer for limiting the transmission of oxygen and / or moisture in the atmosphere through the multilayer structure. The barrier layer comprises aluminum and / or polyhydroxyalkanoate.

[0048] For example, the barrier may comprise only an aluminum layer. In such an embodiment, the aluminum barrier layer preferably has a thickness of about 3 microns to about 13 microns. In other embodiments, the barrier layer may be provided as a layer comprising polyhydroxyalkanoate. In other embodiments, the barrier layer may comprise an aluminum sublayer and a polyhydroxyalkanoate sublayer.

[0049] When the polyhydroxyalkanoate is present in the barrier layer, the polyhydroxyalkanoate may include a homopolymer, a copolymer, or a terpolymer.

[0050] Thus, the barrier layer comprises a polyhydroxyalkanoate copolymer, such as poly(3-hydroxybutyrate-3-hydroxyhexanoate) (P3HB-co-P3HHx). Generally, the barrier layer may comprise from about 1.0 wt% to about 15.0 wt% of at least one polyhydroxyalkanoate, the at least one polyhydroxyalkanoate comprising from about 25 mol% to about 50 mol% of 3-hydroxyalkanoate monomer residues selected from the group consisting of 3-hydroxyvalerate, 3-hydroxyhexanoate, 3-hydroxyoctanoate, 3-hydroxydecanoate, and mixtures thereof.

[0051] In other embodiments, the barrier layer may comprise a polyhydroxyalkanoate terpolymer made from about 75 mol % to about 99.9 mol % of 3-hydroxybutyrate monomer residues, about 0.1 mol % to about 25 mol % of 3-hydroxyhexanoate monomer residues, and about 0.1 mol % to about 25 mol % of a third 3-hydroxyalkanoate monomer residue selected from the group consisting of 3-hydroxyvalerate, 3-hydroxyoctanoate, 3-hydroxydecanoate, and mixtures thereof.

[0052] In certain embodiments, the heat sealable layer may further comprise about 1 wt % to 90 wt % of at least one additional biodegradable polymer. Such additional biodegradable polymer is preferably selected from the group consisting of polybutylene succinate, polycaprolactone, polybutylene succinate-adipate, polybutylene adipate-terephthalate, polylactic acid, cellulose acetate, and mixtures thereof.

[0053] The barrier layer preferably further comprises a nucleating agent. Preferably, the heat sealable layer comprises about 0.1 wt % to about 5 wt % of at least one nucleating agent selected from the group consisting of erythritol, pentaerythritol, dipentaerythritol, artificial sweeteners, stearic acid, sorbitol, mannitol, inositol, polyester wax, nanoclay, behenamide, erucamide, stearamide, oleamide, polyhydroxybutyrate, boronitrile and mixtures thereof.

[0054] In some cases, the barrier layer may further comprise about 1 wt% to about 25 wt% of at least one filler selected from the group consisting of clay, calcium carbonate, talc, kaolinite, montmorillonite, bentonite, silica, chitin, titanium dioxide, nanoclay, and mixtures thereof. A particularly preferred filler is talc.

[0055] In some embodiments, the multilayer structure may include a layer of nylon film in addition to the heat sealable layer, the aluminum barrier layer, and the print layer. When the additional nylon layer is present, it imparts additional strength, durability, and puncture resistance to the multilayer structure.

[0056] When a nylon film layer is present, it is typically stretch oriented, preferably biaxially oriented. The nylon layer also preferably has a thickness of about 5 microns to about 15 microns.

[0057] The multilayer structure further comprises a biodegradable printing layer, wherein the biodegradable printing layer comprises at least one form of polyhydroxyalkanoate and / or cellulose. The biodegradable printing layer is preferably printed with product packaging information using flexographic printing, gravure printing or digital printing methods.

[0058] Similar to the heat sealable layer described above, the printing layer may comprise polyhydroxyalkanoates in the form of homopolymers, copolymers or terpolymers. Alternatively, according to some embodiments, the printing layer may be made of a biodegradable cellulose-based material.

[0059] For example, the biodegradable print layer comprises a polyhydroxyalkanoate copolymer, such as poly(3-hydroxybutyrate-3-hydroxyhexanoate) (P3HB-co-P3HHx).

[0060] Typically, the biodegradable print layer comprises from about 1.0 wt % to about 15.0 wt % of at least one polyhydroxyalkanoate comprising from about 25 mol % to about 50 mol % of monomeric residues of a 3-hydroxyalkanoate selected from the group consisting of 3-hydroxyvalerate, 3-hydroxyhexanoate, 3-hydroxyoctanoate, 3-hydroxydecanoate, and mixtures thereof.

[0061] In other embodiments, the biodegradable print layer may include a polyhydroxyalkanoate terpolymer made from about 75 mol % to about 99.9 mol % of 3-hydroxybutyrate monomer residues, about 0.1 mol % to about 25 mol % of 3-hydroxyhexanoate monomer residues, and about 0.1 mol % to about 25 mol % of a third 3-hydroxy fatty acid ester monomer residue selected from the group consisting of 3-hydroxyvalerate, 3-hydroxyoctanoate, 3-hydroxydecanoate, and mixtures thereof.

[0062] Typically, the polyhydroxyalkanoate in the biodegradable print layer has a weight average molecular weight of about 50,000 Daltons to about 2,500,000 Daltons (determined according to ASTM D5296-05).

[0063] Generally, the amount of polyhydroxyalkanoate in the biodegradable print layer is preferably from about 10 wt % to about 99 wt % of the heat sealable layer.

[0064] According to certain embodiments, the printing layer may also include about 1 wt% to 90 wt% of at least one additional biodegradable polymer. Such additional biodegradable polymers are preferably selected from the group consisting of polybutylene succinate, polycaprolactone, polybutylene succinate-adipate, polybutylene adipate-terephthalate, polylactic acid, cellulose acetate, and mixtures thereof. In addition, the printing layer generally also includes a nucleating agent. Preferably, the heat sealable layer includes about 0.1 wt% to about 5 wt% of at least one nucleating agent selected from the group consisting of erythritol, pentaerythritol, dipentaerythritol, artificial sweeteners, stearic acid, sorbitol, mannitol, inositol, polyester wax, nanoclay, behenamide, erucamide, stearamide, oleamide, polyhydroxybutyrate, boronitride, and mixtures thereof.

[0065] Preferably, the biodegradable print layer has a thickness of about 5 microns to about 25 microns.

[0066] The above-mentioned layers are bonded together to form a multilayer structure by one or more adhesives. Preferably, the adhesive comprises a biodegradable material (determined according to ASTM D5338) and / or a compostable material (determined according to ASTM D6400). For example, in some embodiments, the layers of the multilayer structure can be bonded together by at least one adhesive, the adhesive comprising at least one polymer selected from the group consisting of polycaprolactone, isocyanate, polyurethane, polybutylene succinate-adipate, polybutylene adipate-terephthalate, polyhydroxyalkanoate, polylactic acid and mixtures thereof.

[0067] The multilayer structure prepared according to the present disclosure provides good barrier properties for the storage and preservation of food products packaged in retort pouches.

[0068] In particular, in certain embodiments, the multilayer structure preferably has a flow rate of less than 0.45 ml / m 2 / 24h oxygen transmission rate (determined according to ASTM D3985). In comparison, under the same test conditions, polyethylene terephthalate (PET) films generally have an oxygen transmission rate of about 15 to about 90 ml / m 2 / 24h oxygen transmission rate. Under the same test conditions, polyethylene (PE) film usually has an oxygen transmission rate of about 1550 to about 2500 ml / m 2 / 24h oxygen transmission rate.

[0069] In addition, the multilayer structure also preferably has a thickness of less than 0.2 g / m 2 / 24h water vapor transmission rate (determined according to ASTM F1249). In comparison, under the same test conditions, polyethylene terephthalate (PET) film generally has a water vapor transmission rate of about 1.5 ml / m 2 / 24h to about 80ml / m 2 / 24h water vapor transmission rate. Under the same test conditions, polyethylene (PE) film usually has a water vapor transmission rate of about 1.5ml / m 2 / 24h to about 15.5ml / m 2 / 24h water vapor transmission rate.

[0070] The retort pouch also preferably has a shelf life of at least 18 months (as measured in accordance with ASTM E2454).

[0071] Furthermore, all layers of the multilayer structure preferably have a melting point greater than 120° C. (measured according to ASTM E794-06). More preferably, all layers of the multilayer structure preferably have a melting point greater than 150° C. (measured according to ASTM E794-06). Since retort packaged foods are typically cooked / sterilized in retort pouches at a temperature of about 136° C., the higher melting point of the material used to form the pouch ensures that the integrity of the pouch is maintained during the cooking process of the food.

[0072] At the same time, at least the heat sealable layer and the printed layer of the multi-layer sidewall structure are biodegradable. Preferably, at least the heat sealable layer and the printed layer of the multi-layer sidewall structure are also home compostable. If the optional nylon layer is omitted, all polymer-based layers of the multi-layer sidewall structure are preferably biodegradable and / or home compostable.

[0073] The following embodiments further illustrate the present disclosure:

[0074] Embodiment 1. A retort food bag having at least one side wall and a bag seal, wherein the at least one side wall is a multi-layer structure, comprising:

[0075] a biodegradable heat-sealable layer comprising a polyhydroxyalkanoate;

[0076] a barrier layer comprising aluminum and / or polyhydroxyalkanoate;

[0077] Optionally, a nylon layer; and

[0078] a biodegradable printing layer comprising polyhydroxyalkanoates and / or cellulose,

[0079] The layers are bonded together by one or more adhesives to form a multilayer structure.

[0080] Embodiment 2. The retort food bag of embodiment 1, wherein the biodegradable heat-sealable layer comprises:

[0081] about 10 wt % to about 99 wt % of a polyhydroxyalkanoate;

[0082] about 1 wt % to 90 wt % of at least one biodegradable polymer selected from the group consisting of polybutylene succinate, polycaprolactone, polybutylene succinate-adipate, polybutylene adipate-terephthalate, polylactic acid, cellulose acetate, and mixtures thereof;

[0083] about 0.1 wt % to about 5 wt % of at least one nucleating agent selected from the group consisting of erythritol, pentaerythritol, dipentaerythritol, artificial sweeteners, stearates, sorbitol, mannitol, inositol, polyester waxes, nanoclays, behenamide, erucamide, stearamide, oleamide, polyhydroxybutyrate, boronitrile, and mixtures thereof; and

[0084] Optionally, about 1 wt% to about 25 wt% of at least one filler selected from the group consisting of clay, calcium carbonate, talc, kaolinite, montmorillonite, bentonite, silica, chitin, titanium dioxide, nanoclay, and mixtures thereof.

[0085] Embodiment 3. The retort food pouch of embodiment 1 or 2, wherein the polyhydroxyalkanoate in the biodegradable heat-sealable layer comprises poly(3-hydroxybutyrate-3-hydroxyhexanoate) (P3HB-co-P3HHx).

[0086] Embodiment 4. A retort food bag according to any one of the preceding embodiments, wherein the biodegradable heat-sealable layer comprises about 1.0 wt % to about 15.0 wt % of at least one polyhydroxyalkanoate, wherein the polyhydroxyalkanoate comprises about 25 mol % to about 50 mol % of monomer residues of 3-hydroxyalkanoate, wherein the 3-hydroxyalkanoate is selected from the group consisting of 3-hydroxyvalerate, 3-hydroxyhexanoate, 3-hydroxyoctanoate, 3-hydroxydecanoate and mixtures thereof.

[0087] Embodiment 5. A retort food bag according to any one of the preceding embodiments, wherein the biodegradable heat-sealable layer comprises a polyhydroxyalkanoate terpolymer, wherein the polyhydroxyalkanoate terpolymer is made of about 75 mol % to about 99.9 mol % of 3-hydroxybutyrate monomer residues, about 0.1 mol % to about 25 mol % of 3-hydroxyhexanoate monomer residues, and about 0.1 mol % to about 25 mol % of a third 3-hydroxy fatty acid ester monomer residue, wherein the third 3-hydroxy fatty acid ester is selected from the group consisting of 3-hydroxyvalerate, 3-hydroxyoctanoate, 3-hydroxydecanoate, and mixtures thereof.

[0088] Embodiment 6. The retort food pouch of any of the preceding embodiments, wherein the biodegradable heat-sealable layer comprises a polyhydroxyalkanoate having a weight average molecular weight of about 50,000 Daltons to about 2,500,000 Daltons as determined in accordance with ASTM D5296-05. .

[0089] Embodiment 7. The retort food pouch according to any one of the preceding embodiments, wherein the barrier layer comprises:

[0090] about 10 wt % to about 99 wt % of a polyhydroxyalkanoate;

[0091] about 1 wt % to 90 wt % of at least one biodegradable polymer selected from the group consisting of polybutylene succinate, polycaprolactone, polybutylene succinate-adipate, polybutylene adipate-terephthalate, polylactic acid, cellulose acetate, and mixtures thereof;

[0092] about 0.1 wt % to about 25 wt % of at least one nucleating agent selected from the group consisting of erythritol, pentaerythritol, dipentaerythritol, artificial sweeteners, stearates, sorbitol, mannitol, inositol, polyester waxes, nanoclays, behenamide, erucamide, stearamide, oleamide, polyhydroxybutyrate, boronitrile, and mixtures thereof; and

[0093] Optionally, about 1 wt% to about 25 wt% of at least one filler selected from the group consisting of clay, calcium carbonate, talc, kaolinite, montmorillonite, bentonite, silica, chitin, titanium dioxide, nanoclay, and mixtures thereof.

[0094] Embodiment 8. The retort food pouch of embodiment 7, wherein the polyhydroxyalkanoate in the barrier layer comprises poly(3-hydroxybutyrate-3-hydroxyhexanoate) (P3HB-co-P3HHx).

[0095] Embodiment 9. The retort food bag according to embodiment 7 or 8, wherein the barrier layer comprises about 1.0 wt % to about 15.0 wt % of at least one polyhydroxyalkanoate, wherein the polyhydroxyalkanoate comprises about 25 mol % to about 50 mol % of monomer residues of 3-hydroxyalkanoate, wherein the 3-hydroxyalkanoate is selected from the group consisting of 3-hydroxyvalerate, 3-hydroxyhexanoate, 3-hydroxyoctanoate, 3-hydroxydecanoate and mixtures thereof.

[0096] Embodiment 10. A retort food bag according to any one of embodiments 7 to 9, wherein the barrier layer comprises a polyhydroxyalkanoate terpolymer, wherein the polyhydroxyalkanoate terpolymer is made of about 75 mol% to about 99.9 mol% of 3-hydroxybutyrate monomer residues, about 0.1 mol% to about 25 mol% of 3-hydroxyhexanoate monomer residues, and about 0.1 mol% to about 25 mol% of a third 3-hydroxy fatty acid ester monomer residue, wherein the third 3-hydroxy fatty acid ester is selected from the group consisting of 3-hydroxyvalerate, 3-hydroxyoctanoate, 3-hydroxydecanoate, and mixtures thereof.

[0097] Embodiment 11. The retort food pouch of any one of embodiments 7 to 10, wherein the barrier layer comprises a polyhydroxyalkanoate having a weight average molecular weight of about 50,000 Daltons to about 2,500,000 Daltons as determined in accordance with ASTM D5296-05.

[0098] Embodiment 12. The retort food pouch of Embodiment 7, wherein the barrier layer comprises aluminum.

[0099] Embodiment 13. The retort food pouch according to any of the preceding embodiments, wherein the multilayer structure has a total thickness of about 25 microns to about 75 microns.

[0100] Embodiment 14. The retort food pouch of any of the preceding embodiments, wherein the aluminum barrier layer has a thickness of about 3 microns to about 13 microns.

[0101] Embodiment 15. The retort food pouch of any of the preceding embodiments, wherein the multilayer structure comprises a biaxially oriented nylon layer having a thickness of about 5 microns to about 15 microns.

[0102] Embodiment 16. The retort food pouch of any of the preceding embodiments, wherein the biodegradable printing layer comprises:

[0103] about 10 wt % to about 99 wt % of a polyhydroxyalkanoate;

[0104] about 1 wt % to 90 wt % of at least one biodegradable polymer selected from the group consisting of polybutylene succinate, polycaprolactone, polybutylene succinate-adipate, polybutylene adipate-terephthalate, polylactic acid, cellulose acetate, and mixtures thereof; and

[0105] About 0.1 wt % to about 5 wt % of at least one nucleating agent selected from the group consisting of erythritol, pentaerythritol, dipentaerythritol, artificial sweeteners, stearates, sorbitol, mannitol, inositol, polyester waxes, nanoclays, behenamide, erucamide, stearamide, oleamide, polyhydroxybutyrate, boronitrile, and mixtures thereof.

[0106] Embodiment 17. The retort food pouch of embodiment 16, wherein the polyhydroxyalkanoate in the biodegradable printing layer comprises poly(3-hydroxybutyrate-3-hydroxyhexanoate) (P3HB-co-P3HHx).

[0107] Embodiment 18. The retort food bag according to embodiment 16 or 17, wherein the biodegradable printing layer comprises about 1.0 wt % to about 15.0 wt % of at least one polyhydroxyalkanoate, wherein the polyhydroxyalkanoate comprises about 25 mol % to about 50 mol % of monomer residues of 3-hydroxyalkanoate, wherein the 3-hydroxyalkanoate is selected from the group consisting of 3-hydroxyvalerate, 3-hydroxyhexanoate, 3-hydroxyoctanoate, 3-hydroxydecanoate, and mixtures thereof.

[0108] Embodiment 19. A retort food bag according to any one of embodiments 16 to 18, wherein the biodegradable printing layer comprises a polyhydroxyalkanoate terpolymer, wherein the polyhydroxyalkanoate terpolymer is made of about 75 mol% to about 99.9 mol% of 3-hydroxybutyrate monomer residues, about 0.1 mol% to about 25 mol% of 3-hydroxyhexanoate monomer residues, and about 0.1 mol% to about 25 mol% of a third 3-hydroxy fatty acid ester monomer residue, wherein the third 3-hydroxy fatty acid ester is selected from the group consisting of 3-hydroxyvalerate, 3-hydroxyoctanoate, 3-hydroxydecanoate, and mixtures thereof.

[0109] Embodiment 20. The retort food pouch of any one of embodiments 16 to 19, wherein the biodegradable print layer comprises a polyhydroxyalkanoate having a weight average molecular weight of about 50,000 Daltons to about 2,500,000 Daltons as determined according to ASTM D5296-05.

[0110] Embodiment 21. The retort food pouch of any one of embodiments 16 to 20, wherein the biodegradable print layer has a thickness of about 5 to about 25 microns.

[0111] Embodiment 22. The retort food pouch of any of the preceding embodiments, wherein the biodegradable print layer is printed using flexographic, gravure, or digital printing methods.

[0112] Embodiment 23. A retort food pouch according to any of the preceding embodiments, wherein the layers are bonded together by at least one adhesive comprising at least one polymer selected from the group consisting of polycaprolactone, isocyanate, polyurethane, polybutylene succinate-adipate, polybutylene adipate-terephthalate, polyhydroxyalkanoates, polylactic acid, and mixtures thereof.

[0113] Embodiment 24. The retort food pouch of any of the preceding embodiments, wherein all layers of the multilayer structure have a melting point greater than 120°C, as determined according to ASTM E794-06.

[0114] Embodiment 25. The retort food pouch of any of the preceding embodiments, wherein the retort food pouch has a shelf life of at least 18 months as measured according to ASTM E2454.

[0115] Embodiment 26. The retort food pouch according to any one of the preceding embodiments, wherein the multilayer structure has a 2 / 24h oxygen transmission rate, oxygen transmission rate is measured according to ASTM D3985.

[0116] Embodiment 27. The retort food bag according to any of the preceding embodiments, wherein the multilayer structure has a thickness of less than 0.2 g / m 2 / 24h water vapor transmission rate, the water vapor transmission rate is measured according to ASTM F1249.

[0117] Example

[0118] The following non-limiting examples illustrate various additional aspects of the invention. Unless otherwise indicated, temperatures are in degrees Celsius and percentages are by weight based on the dry weight of the formulation.

[0119] Example 1

[0120] In this example, a series of formulations suitable for biodegradable films were compounded in an Entek twin-screw extruder. The composition (weight percentage) of the formulations is shown in Table 1 below:

[0121] Table 1

[0122] <![CDATA[ Components ]]> <![CDATA[ Recipe 1 ]]> <![CDATA[ Recipe 2 ]]> <![CDATA[ Recipe 3 ]]> <![CDATA[ Recipe 4 ]]> PHB-co-PHxx 46％ 51％ 46％ 51％ PHB 5％ - 5％ - PBS 23％ 23％ - - PBAT - - 23％ 23％ Behenamide 2％ 2％ 2％ 2％ talc 22％ 22％ 22％ 22％ clay 2％ 2％ 2％ 2％

[0123] Example 1

[0124] In this example, the resin formulation from Example 1 above was converted into a blown film (1.25 mil) and tested for heat resistance under the following conditions: conventional convection oven (120°C, 5 minutes), boiling water (100°C / 30 minutes), and microwave oven (1000W, 90 seconds). The shrinkage percentage of the film in the machine direction (MD) and transverse direction (TD) was evaluated. The results are shown in Table 2.

[0125]

[0126] The foregoing descriptions of the preferred embodiments of the present invention are for illustration and description purposes. They are not intended to be exhaustive or to limit the invention to the precise form disclosed. Obvious modifications or variations may be made in light of the above teachings. The embodiments are selected and described in order to provide the best illustration of the principles of the invention and its practical application, thereby enabling one of ordinary skill in the art to utilize the invention in various embodiments and to make various modifications to suit the particular use contemplated. All such modifications and variations are within the scope of the invention as determined by the appended claims when interpreted in accordance with the scope of fair, legal and equitable authorization.

Claims

1. A retort food bag having at least one side wall and a bag seal, wherein the at least one side wall is a multi-layer structure, comprising: a biodegradable heat-sealable layer comprising a polyhydroxyalkanoate; a barrier layer comprising aluminum and / or polyhydroxyalkanoate; Optionally, a nylon layer; and A biodegradable printed layer comprising a polyhydroxyalkanoate, The layers are bonded together by one or more adhesives to form a multilayer structure.

2. The retort food pouch according to claim 1, wherein the biodegradable heat-sealable layer comprises: 10 wt % to 99 wt % of polyhydroxyalkanoate; 1 wt % to 90 wt % of at least one biodegradable polymer selected from the group consisting of polybutylene succinate, polycaprolactone, polybutylene succinate-adipate, polybutylene adipate-terephthalate, polylactic acid, cellulose acetate, and mixtures thereof; 0.1 wt % to 5 wt % of at least one nucleating agent selected from the group consisting of erythritol, pentaerythritol, dipentaerythritol, artificial sweeteners, stearic acid, sorbitol, mannitol, inositol, polyester wax, nanoclay, behenamide, erucamide, stearamide, oleamide, polyhydroxybutyrate, boronitrile, and mixtures thereof; and Optionally, 1 wt% to 25 wt% of at least one filler selected from the group consisting of clay, calcium carbonate, talc, kaolinite, montmorillonite, bentonite, silica, chitin, titanium dioxide, nanoclay and mixtures thereof.

3. The retort food pouch of claim 2, wherein the polyhydroxyalkanoate in the biodegradable heat-sealable layer comprises poly(3-hydroxybutyrate-3-hydroxyhexanoate) (P3HB-co-P3HHx).

4. The retort food pouch according to claim 2, wherein the biodegradable heat-sealable layer comprises 1.0 wt% to 15.0 wt% of at least one polyhydroxyalkanoate, the polyhydroxyalkanoate comprising 25 mol% to 50 mol% of monomer residues of 3-hydroxyalkanoate, the 3-hydroxyalkanoate being selected from the group consisting of 3-hydroxyvalerate, 3-hydroxyhexanoate, 3-hydroxyoctanoate, 3-hydroxydecanoate, and mixtures thereof.

5. The retortable food bag according to claim 2, wherein the biodegradable heat-sealable layer comprises a polyhydroxyalkanoate terpolymer, wherein the polyhydroxyalkanoate terpolymer is made of 75 mol% to 99.9 mol% of 3-hydroxybutyrate monomer residues, 0.1 mol% to 25 mol% of 3-hydroxyhexanoate monomer residues and 0.1 mol% to 25 mol% of a third 3-hydroxyalkanoate monomer residue, wherein the third 3-hydroxyalkanoate is selected from the group consisting of 3-hydroxyvalerate, 3-hydroxyoctanoate, 3-hydroxydecanoate and mixtures thereof.

6. The retort food pouch of claim 2, wherein the biodegradable heat-sealable layer comprises a polyhydroxyalkanoate having a weight average molecular weight of 50,000 to 2,500,000 Daltons, as determined according to ASTM D5296-05.

7. The retort food pouch according to claim 1, wherein the barrier layer comprises: 10 wt % to 99 wt % of polyhydroxyalkanoate; 1 wt % to 90 wt % of at least one biodegradable polymer selected from the group consisting of polybutylene succinate, polycaprolactone, polybutylene succinate-adipate, polybutylene adipate-terephthalate, polylactic acid, cellulose acetate, and mixtures thereof; 0.1 wt % to 25 wt % of at least one nucleating agent selected from the group consisting of erythritol, pentaerythritol, dipentaerythritol, artificial sweeteners, stearate, sorbitol, mannitol, inositol, polyester wax, nanoclay, behenamide, erucamide, stearamide, oleamide, polyhydroxybutyrate, boronitrile, and mixtures thereof; and Optionally, 1 wt% to 25 wt% of at least one filler selected from the group consisting of clay, calcium carbonate, talc, kaolinite, montmorillonite, bentonite, silica, chitin, titanium dioxide, nanoclay and mixtures thereof.

8. The retort food pouch of claim 7, wherein the polyhydroxyalkanoate in the barrier layer comprises poly(3-hydroxybutyrate-3-hydroxyhexanoate) (P3HB-co-P3HHx).

9. The retort food pouch of claim 7, wherein the barrier layer comprises 1.0 wt% to 15.0 wt% of at least one polyhydroxyalkanoate, the polyhydroxyalkanoate comprising 25 mol% to 50 mol% of monomer residues of 3-hydroxyalkanoate selected from the group consisting of 3-hydroxyvalerate, 3-hydroxyhexanoate, 3-hydroxyoctanoate, 3-hydroxydecanoate, and mixtures thereof.

10. The retort food pouch of claim 7, wherein the barrier layer comprises a polyhydroxyalkanoate terpolymer made from 75 mol% to 99.9 mol% of 3-hydroxybutyrate monomer residues, 0.1 mol% to 25 mol% of 3-hydroxyhexanoate monomer residues, and 0.1 mol% to 25 mol% of a third 3-hydroxyalkanoate monomer residue, wherein the third 3-hydroxyalkanoate is selected from the group consisting of 3-hydroxyvalerate, 3-hydroxyoctanoate, 3-hydroxydecanoate, and mixtures thereof.

11. The retort food pouch of claim 7, wherein the barrier layer comprises a polyhydroxyalkanoate having a weight average molecular weight of 50,000 to 2,500,000 Daltons, as determined according to ASTM D5296-05.

12. The retort food pouch of claim 1, wherein the barrier layer comprises aluminum.

13. The retort food pouch of claim 1, wherein the multi-layer structure has a total thickness of 25 to 75 microns.

14. The retort food pouch of claim 1, wherein the aluminum barrier layer has a thickness of 3 to 13 microns.

15. The retort food pouch of claim 1, wherein the multi-layer structure comprises a biaxially oriented nylon layer having a thickness of 5 to 15 microns.

16. The retort food pouch according to claim 1, wherein the biodegradable printing layer comprises: 10 wt % to 99 wt % of polyhydroxyalkanoate; 1 wt % to 90 wt % of at least one biodegradable polymer selected from the group consisting of polybutylene succinate, polycaprolactone, polybutylene succinate-adipate, polybutylene adipate-terephthalate, polylactic acid, cellulose acetate, and mixtures thereof; 0.1 wt % to 5 wt % of at least one nucleating agent selected from the group consisting of erythritol, pentaerythritol, dipentaerythritol, artificial sweeteners, stearic acid, sorbitol, mannitol, inositol, polyester wax, nanoclay, behenamide, erucamide, stearamide, oleamide, polyhydroxybutyrate, boronitrile, and mixtures thereof; and Optionally, 1 wt% to 25 wt% of at least one filler selected from the group consisting of clay, calcium carbonate, talc, kaolinite, montmorillonite, bentonite, silica, chitin, titanium dioxide, nanoclay and mixtures thereof.

17. The retort food pouch of claim 1, wherein the biodegradable print layer comprises a core sublayer and at least one skin sublayer.

18. The retort food pouch of claim 16, wherein the polyhydroxyalkanoate in the biodegradable printing layer comprises poly(3-hydroxybutyrate-3-hydroxyhexanoate) (P3HB-co-P3HHx).

19. The retort food pouch of claim 16, wherein the biodegradable printing layer comprises 1.0 wt% to 15.0 wt% of at least one polyhydroxyalkanoate, the polyhydroxyalkanoate comprising 25 mol% to 50 mol% of monomer residues of 3-hydroxyalkanoate selected from the group consisting of 3-hydroxyvalerate, 3-hydroxyhexanoate, 3-hydroxyoctanoate, 3-hydroxydecanoate, and mixtures thereof.

20. The retort food pouch of claim 16, wherein the biodegradable printing layer comprises a polyhydroxyalkanoate terpolymer made from 75 mol% to 99.9 mol% of 3-hydroxybutyrate monomer residues, 0.1 mol% to 25 mol% of 3-hydroxyhexanoate monomer residues, and 0.1 mol% to 25 mol% of a third 3-hydroxyalkanoate monomer residue, the third 3-hydroxyalkanoate being selected from the group consisting of 3-hydroxyvalerate, 3-hydroxyoctanoate, 3-hydroxydecanoate, and mixtures thereof.

21. The retort food pouch of claim 16, wherein the biodegradable print layer comprises a polyhydroxyalkanoate having a weight average molecular weight of 50,000 to 2,500,000 Daltons, as determined according to ASTM D5296-05.

22. The retort food pouch of claim 1, wherein the biodegradable printing layer has a thickness of 5 to 25 microns.

23. The retort food pouch of claim 1, wherein the biodegradable print layer is printed using a flexographic printing, a gravure printing, or a digital printing method.

24. The retort food pouch of claim 1, wherein the layers are bonded together by at least one adhesive comprising at least one polymer selected from the group consisting of polycaprolactone, isocyanate, polyurethane, polybutylene succinate-adipate, polybutylene adipate-terephthalate, polyhydroxyalkanoates, polylactic acid, and mixtures thereof.

25. The retort food pouch of claim 1, wherein all layers of the multi-layer structure have a melting point greater than 120°C, as determined in accordance with ASTM E794-06.

26. The retort food pouch of claim 1, wherein the retort food pouch has a shelf life of at least 18 months as measured in accordance with ASTM E2454.

27. The retort food bag according to claim 1, wherein the multilayer structure has a viscosity of less than 0.45 ml / m 2 / 24h oxygen transmission rate, oxygen transmission rate is measured according to ASTM D3985.

28. The retort food pouch of claim 1, wherein the multilayer structure has a viscosity of less than 0.2 g / m 2 / 24h water vapor transmission rate, the water vapor transmission rate is measured according to ASTM F1249.

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