Aqueous mixtures of novel poly(hydroxyalkanoates)

Abstract

A biodegradable aqueous mixture for coating a substrate is disclosed. The mixture comprises about 35 to about 75 weight percent water and about 25 to about 65 weight percent solids. The solids comprise, based on the total dry weight of the solids, about 40 to about 99 weight percent of a first poly(hydroxyalkanoate), wherein the first poly(hydroxyalkanoate) consists of at least 1 mole percent of monomeric repeat units of 3-hydroxypropionate ester.

Description

TECHNICAL FIELD

[0001] The present invention relates to biodegradable polymeric compositions. More particularly, the present invention relates to biodegradable coatings for paperboard substrates and the like, made from aqueous mixtures of poly(hydroxyalkanoate) ("PHA"). BACKGROUND

[0002] Disposable articles, such as food service articles, can be readily manufactured from substrates, such as paperboard, which will decompose relatively quickly after landfill disposal. However, simple, uncoated paperboard substrates are generally poor performers because the paperboard will rapidly absorb water and / or grease, thereby affecting the strength of the paperboard. As a result, paperboard-based articles are typically coated with a thin polymeric layer to improve water and grease resistance.

[0003] Coatings made from polymers such as polyethylene (PE), polypropylene (PP), or polyethylene terephthalate (PET) can significantly improve the water and / or grease absorption resistance of paperboard; however, such polymers are not readily biodegradable or decomposable after landfill disposal. As a result, paperboard articles coated with such polymers can exist in landfills for centuries after disposal.

[0004] Accordingly, there is a need to provide a new coating that is completely biodegradable for substrates, such as food service articles. Moreover, if, there is also a need for such a biodegradable coating to have good water and grease resistance, i.e., water and grease resistance comparable to conventional non-biodegradable coatings.

[0005] Furthermore, there is also a need to provide a biodegradable coating that can be applied to a substrate at a relatively low coating weight, while still providing barrier properties, such as low oxygen transmission rates and water vapor transmission rates. There is also a need to provide a substrate coated with such a material. SUMMARY

[0006] In response to the above and other needs, the present invention provides a biodegradable aqueous mixture for coating a substrate. According to one embodiment, such aqueous mixture is composed of about 35 to about 75 weight percent water and about 25 to about 65 weight percent solids. The solids, in turn, are composed of about 40 to about 99 weight percent, based on the total dry weight of the solids, of a first poly(hydroxyalkanoate).

[0007] Such first poly(hydroxyalkanoate) is composed of at least 1 mole percent monomeric repeat units of 3-hydroxypropionate. Preferably, the first poly(hydroxyalkanoate) is composed of at least 50 mole percent monomeric repeat units of 3-hydroxypropionate, and even more preferably, 75 mole percent monomeric repeat units of 3-hydroxypropionate.

[0008] In certain embodiments, the first poly(hydroxyalkanoate) in the aqueous mixture preferably consists of poly(3-hydroxypropionate).

[0009] In other embodiments, the first poly(hydroxyalkanoate) in the aqueous mixture is preferably a copolymer or terpolymer. Such copolymers or terpolymers consist of the following components:

[0010] a first repeat unit that is (3-hydroxypropionate),

[0011] a second repeat unit according to Formula I

[0012]

[0013] optionally, a third repeat unit according to Formula II,

[0014]

[0015] wherein R1and R2are each independently selected from the group consisting of linear or branched alkyl groups having 1 to 22 carbon atoms.

[0016] In some embodiments, the first poly(hydroxyalkanoate) is preferably a copolymer and R1is methyl. In some cases, such poly(hydroxyalkanoate) copolymers preferably consist of about 10 to about 90 mole percent of the first repeat unit and about 90 to about 10 mole percent of the second repeat unit. More preferably, the poly(hydroxyalkanoate) copolymers consist of about 30 to about 70 mole percent of the first repeat unit and about 70 to about 30 mole percent of the second repeat unit.

[0017] In other embodiments, the first poly(hydroxyalkanoate) is preferably a terpolymer, wherein R1is methyl and R2is propyl. In some cases, such poly(hydroxyalkanoate) terpolymers preferably consist of about 15 to about 75 mole percent of the first repeat unit, about 75 to about 15 mole percent of the second repeat unit, and about 1 to about 5 mole percent of the third repeat unit. More preferably, the terpolymers preferably consist of about 30 to about 60 mole percent of the first repeat unit, about 60 to about 30 mole percent of the second repeat unit, and about 1 to about 5 mole percent of the third repeat unit.

[0018] According to certain embodiments, the first poly(hydroxyalkanoate) preferably has a weight average molecular weight of at least 50000 Daltons, as determined according to ASTM D4001-20. More preferably, the first poly(hydroxyalkanoate) has a weight average molecular weight of about 50000 to about 1000000 Daltons, as determined according to ASTM D4001-20.

[0019] In some embodiments, the solids of the aqueous mixture can comprise a second poly(hydroxyalkanoate) and the first poly(hydroxyalkanoate) according to the present application. This second poly(hydroxyalkanoate) does not comprise monomeric repeating units of 3-hydroxypropionic acid ester.

[0020] In other embodiments, the solids of the aqueous mixture can further comprise at least one biodegradable polymer selected from the group consisting of polybutylene succinate, polybutylene succinate-polybutylene adipate, polybutylene adipate-polybutylene terephthalate, polycaprolactone, polylactic acid, polyvinyl alcohol, polyglycolic acid, polyglycolic acid / polylactic acid copolymer, cellulose acetate, nanocellulose, isosorbide ester, and mixtures thereof.

[0021] In some embodiments, the mixture preferably further comprises from about 0.01 to about 5.0 weight percent of at least one surfactant selected from the group consisting of polysorbates, aromatic polyethylene oxides, sorbitan derivatives, block copolymers of polyethylene oxide and polypropylene oxide, polyglycol ethers, polyvinyl alcohol, alkyl sulfates, alkyl phosphates, stearates, and mixtures thereof.

[0022] According to certain embodiments, the mixture preferably further comprises from about 0.01 to about 5.0 weight percent of at least one rheology modifier selected from the group consisting of polysaccharides, acrylate-based emulsion copolymers, viscosity-reducing agents, and viscosity-increasing agents.

[0023] In some cases, the mixture preferably further comprises from about 0.01 to about 2.5 weight percent of at least one wetting and dispersing agent.

[0024] According to certain embodiments, the mixture preferably further comprises from about 0.01 to about 0.5 weight percent of at least one biocide or biostat.

[0025] In certain embodiments, the mixture preferably further comprises from about 0.1 to about 5.0 weight percent of at least one coalescing agent selected from the group consisting of biomass succinic acid-based coalescing solvents, 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate, dimethyl carbonate, methanol, ethanol, ketones, acetates, and / or mixtures thereof.

[0026] In some embodiments, the mixture further preferably comprises from about 0.05 to about 1 weight percent of at least one antifoam agent selected from the group consisting of polyether siloxanes, polyamide particles, and mixtures thereof.

[0027] In some embodiments, the mixture preferably further comprises from about 1 weight percent to about 35 weight percent of at least one filler selected from the group consisting of clay, calcium carbonate, talc, kaolinite, montmorillonite, bentonite, silica, chitin, titanium dioxide, nanoclay, or mixtures thereof.

[0028] In certain embodiments, the mixture comprises poly(hydroxyalkanoate) particles having a Dv(90) particle size of no more than about 20 microns, more preferably no more than about 10 microns, as determined using ISO 8130-13:201.

[0029] According to certain embodiments, the mixture preferably has an oxygen transmission rate of less than 50 cc / m 2 / 24h, as determined according to ASTM D3985, when applied as a coating for a substrate. In certain cases, the mixture has an oxygen transmission rate of 10 to 50 cc / m 2 / 24h, as determined according to ASTM D3985, when applied as a coating for a substrate.

[0030] In certain embodiments, the mixture has a water vapor transmission rate of less than 50 g / m 2 / 24h, as determined according to ASTM F1249, when applied as a coating for a substrate. In certain cases, the mixture has a water vapor transmission rate of 10 to 50 g / m 2 / 24h, as determined according to ASTM F1249, when applied as a coating for a substrate.

[0031] In another aspect, the present application also provides a coated substrate. Such a coated substrate comprises a paperboard substrate having at least a first surface and a second surface; and a coating on at least the first surface, wherein the coating is formed by applying the above-mentioned biodegradable aqueous mixture. DETAILED DESCRIPTION

[0032] Again, the present application provides a biodegradable aqueous mixture for coating a substrate. Generally, the aqueous mixture can take the form of a suspension, emulsion, or colloid.

[0033] As used hereinabove and hereinbelow, a "suspension" refers to a heterogeneous mixture of at least two substances (a dispersed material and a dispersion medium). The particles of a suspension can be separated using filtration. The particles of a suspension also have a greater tendency to settle under the influence of gravity compared to certain other mixtures, such as a colloid.

[0034] As used herein, a "colloid" is a heterogeneous mixture with a particle size intermediate between a solution and a suspension. The dispersed particles are uniformly dispersed throughout the dispersion medium, i.e., liquid water. The particles present in a colloid will exhibit a light scattering effect known as the Tyndall effect.

[0035] As used herein, an "emulsion" is a type of colloid in which an emulsifier (e.g., a surfactant) is present.

[0036] Typically, the mixture includes water and solids. Typically, the mixture includes about 35 to about 75 weight percent water and about 25 to about 65 weight percent solids. In some cases, the mixture more preferably includes about 45 to about 55 weight percent water and about 45 to about 55 weight percent solids.

[0037] The solids of the mixture, in turn, include at least a poly(hydroxyalkanoate), and can also include other biopolymers and / or additives. Typically, the solids include about 40 to about 99 weight percent of the first poly(hydroxyalkanoate), based on the total dry weight of the solids. In some embodiments, the solids more preferably include about 40 to about 50 weight percent of the first poly(hydroxyalkanoate), based on the total dry weight of the solids.

[0038] Importantly, the above first poly(hydroxyalkanoate) consists of at least 1 mole percent monomeric repeat units of 3-hydroxypropionic acid ester. Preferably, the first poly(hydroxyalkanoate) consists of at least 50 mole percent monomeric repeat units of 3-hydroxypropionic acid ester, even more preferably, 75 mole percent monomeric repeat units of 3-hydroxypropionic acid ester.

[0039] Typically, the first poly(hydroxyalkanoate) of the composition can be a homopolymer, a copolymer, or a terpolymer. Thus, in certain embodiments, the first poly(hydroxyalkanoate) is a homopolymer, i.e., a poly(3-hydroxypropionic acid ester).

[0040] In other embodiments, the poly(hydroxyalkanoate) is a copolymer or a terpolymer consisting of:

[0041] a first repeat unit that is (3-hydroxypropionic acid ester),

[0042] a second repeat unit according to Formula I

[0043]

[0044] optionally, a third repeat unit according to Formula II,

[0045]

[0046] wherein R1and R2are each independently selected from the group consisting of linear or branched alkyl groups having 1 to 22 carbon atoms.

[0047] In some embodiments, the poly(hydroxyalkanoate) is more preferably a copolymer, and R1is methyl. In these embodiments, the poly(hydroxyalkanoate) copolymer typically consists of about 10 to about 90 mole percent of the first repeat unit and about 90 to about 10 mole percent of the second repeat unit. More preferably, the poly(hydroxyalkanoate) copolymer consists of about 30 to about 70 mole percent of the first repeat unit and about 70 to about 30 mole percent of the second repeat unit.

[0048] In other embodiments, the poly(hydroxyalkanoate) is more preferably a terpolymer, wherein R1is methyl and R2is propyl. In these embodiments, the poly(hydroxyalkanoate) terpolymer typically consists of about 15 to about 75 mole percent of the first repeat unit, about 75 to about 15 mole percent of the second repeat unit, and about 1 to about 5 mole percent of the third repeat unit. More preferably, the terpolymer preferably consists of about 30 to about 60 mole percent of the first repeat unit, about 60 to about 30 mole percent of the second repeat unit, and about 1 to about 5 mole percent of the third repeat unit.

[0049] The first poly(hydroxyalkanoate) typically has a weight average molecular weight of at least 50,000 Daltons when determined according to ASTM D4001-20. More preferably, the first poly(hydroxyalkanoate) has a weight average molecular weight of about 50,000 to about 1,000,000 Daltons when determined according to ASTM D4001-20.

[0050] While the first poly(hydroxyalkanoate) can be prepared by fermentation in a bioreactor, in some embodiments, the first poly(hydroxyalkanoate) is preferably prepared synthetically by ring-opening polymerization of a lactone. For example, the repeat units of 3-hydroxypropionic acid can be formed from ring-opening polymerization of beta-propiolactone.

[0051] When synthesized in this manner, it has been found that the first poly(hydroxyalkanoate) particles so formed are typically smaller in size than poly(hydroxyalkanoate) particles formed by biological fermentation. In some embodiments, the mixture includes poly(hydroxyalkanoate) particles having a Dv(90) particle size of no more than about 20 microns, more preferably no more than about 10 microns, as determined using ISO 8130-13:201.

[0052] In certain instances, the solids of the aqueous mixture can include a second poly(hydroxyalkanoate) in addition to the first poly(hydroxyalkanoate). This second poly(hydroxyalkanoate) does not include monomeric repeat units of 3-hydroxypropionic acid ester. For example, the second poly(hydroxyalkanoate) can include poly(hydroxybutyrate) or poly-3-hydroxybutyrate-poly 3-hydroxyhexanoate ("P(3HB-co-3HHx)"). When present, the second poly(hydroxyalkanoate) typically comprises about 1 to about 50 weight percent of the solids.

[0053] Further, the solids of the aqueous mixture can also include at least one biodegradable polymer selected from the group consisting of polybutylene succinate, polybutylene succinate-polybutylene adipate ("PBSA"), polybutylene adipate-polybutylene terephthalate ("PBAT"), polycaprolactone, polylactic acid, polyvinyl alcohol, polyglycolic acid, polyglycolic acid / polylactic acid copolymer, cellulose acetate, nanocellulose, isosorbide ester, and mixtures thereof. In more preferred embodiments, the solids can include PBSA and / or PBAT. When present, the additional biopolymer typically comprises about 1 to about 50 weight percent of the solids.

[0054] As noted above, the mixture can also include various additives in addition to the biopolymers described above.

[0055] For example, in some embodiments, the mixture can include about 0.01 weight percent to about 5.0 weight percent of at least one surfactant selected from the group consisting of polysorbates, aromatic polyethylene oxides, sorbitan derivatives, block copolymers of polyethylene oxide and polypropylene oxide, polyglycol ethers, polyvinyl alcohol, alkyl sulfates, alkyl phosphates, stearates, and mixtures thereof.

[0056] In certain embodiments, the mixture can also include about 0.01 weight percent to about 5.0 weight percent of at least one rheology modifier selected from the group consisting of polysaccharides, acrylate-based emulsion copolymers, viscosity-reducing agents, and viscosity-increasing agents.

[0057] The mixture can also include about 0.01 weight percent to about 2.5 weight percent of at least one wetting and dispersing agent, i.e., a dual-function additive that provides both wetting and dispersing functions for the solids in the mixture. Examples of suitable wetting and dispersing agents include polysorbates, polyesters, ethoxylates, and amphiphilic chemicals.

[0058] According to certain embodiments, the mixture preferably also includes about 0.01 weight percent to about 0.5 weight percent of at least one biocide or biostat.

[0059] Additionally, in certain embodiments, the mixture can further include from about 0.1 weight percent to about 5.0 weight percent of at least one coalescing agent selected from the group consisting of biomass succinic acid based coalescing solvents, 2,2,4-trimethyl-l,3-pentanediol monoisobutyrate, dimethyl carbonate, methanol, ethanol, ketones, acetates, and / or mixtures thereof.

[0060] In some embodiments, the mixture further preferably includes from about 0.05 to about 1 weight percent of at least one defoaming agent selected from the group consisting of polyether siloxanes, polyamide particles, and mixtures thereof.

[0061] In some embodiments, the mixture preferably further includes from about 1 weight percent to about 35 weight percent of at least one filler selected from the group consisting of clay, calcium carbonate, talc, kaolinite, montmorillonite, bentonite, silica, chitin, titanium dioxide, nanoclay, or mixtures thereof.

[0062] The mixture of the present application can be prepared by mixing the water, the first polyhydroxyalkanoate, any second polyhydroxyalkanoate, and any additives in a mixing vessel. Typically, the components of the mixture are mixed using a high shear mixer, such as a Silverson mixer. Alternatively, the components of the mixture can be mixed in a pressurized vessel, such as a Parr reactor.

[0063] The present application also provides a coated substrate. The substrate material is typically a paperboard material having a first surface and a second surface. A coating of the above-described biodegradable aqueous mixture is applied to at least the first surface of the substrate. In some cases, both the first and second surfaces of the substrate are coated.

[0064] According to certain embodiments, the mixture preferably has an oxygen transmission rate of less than 50 cc / m2 / 24 h as determined according to ASTM D3985 when applied as a coating on a substrate. In some cases, the mixture has an oxygen transmission rate of from 10 to 50 cc / m2 / 24 h as determined according to ASTM D3985 when applied as a coating on a substrate. 2 / 24 h as determined according to ASTM D3985 when applied as a coating on a substrate. In some cases, the mixture has an oxygen transmission rate of from 10 to 50 cc / m2 / 24 h as determined according to ASTM D3985 when applied as a coating on a substrate. 2

[0065] In certain embodiments, the mixture has a water vapor transmission rate of less than 50 g / m2 / 24 h as determined according to ASTM F1249 when applied as a coating on a substrate. In some cases, the mixture has a water vapor transmission rate of from 10 to 50 g / m2 / 24 h as determined according to ASTM F1249 when applied as a coating on a substrate. 2 / 24 h as determined according to ASTM F1249 when applied as a coating on a substrate. In some cases, the mixture has a water vapor transmission rate of from 10 to 50 g / m2 / 24 h as determined according to ASTM F1249 when applied as a coating on a substrate. 2

[0066] ​​In another aspect, the present application also provides a coated substrate. Such a coated substrate includes a paperboard substrate having at least a first surface and a second surface; and a coating on at least the first surface, wherein the coating is formed by applying the above-described biodegradable aqueous mixture.

[0067] The aqueous mixture is typically applied using a rod, gravure printing, or air knife coating application techniques, and then dried to provide a solid coating on the substrate.

[0068] Once dried and cured, the coating weight is typically from about 5 to about 20 g / m 2 . This is a relatively low coating weight for a biodegradable coating. Coatings formed from biodegradable polymers are more typically applied with a coating weight of about 20 to about 40 g / m 2 , as measured according to ASTM F2117.

[0069] Despite these relatively low coating weights, it has been found that the coatings of the present application provide excellent barrier properties.

[0070] As noted above, when applied as a substrate coating, the mixture preferably has an oxygen transmission rate of less than 50 cc / m 2 / 24h, as measured according to ASTM D3985. In certain cases, when applied as a substrate coating, the mixture has an oxygen transmission rate of 10 to 50 cc / m 2 / 24h, as measured according to ASTM D3985.

[0071] With respect to water vapor transmission rate, when applied as a substrate coating, the mixture has a water vapor transmission rate of less than 50 g / m 2 / 24h, as measured according to ASTM F1249. In certain cases, when applied as a substrate coating, the mixture has a water vapor transmission rate of 10 to 50 g / m 2 / 24h, as measured according to ASTM F1249.

[0072] The present application is further illustrated by the following embodiments:

[0073] Embodiment 1. A biodegradable aqueous mixture for coating a substrate, the mixture comprising:

[0074] about 35 to about 75 weight percent water and about 25 to about 65 weight percent solids,

[0075] wherein the solids comprise, based on the total dry weight of the solids, about 40 to about 99 weight percent of a first poly(hydroxyalkanoate), and

[0076] wherein the first poly(hydroxyalkanoate) comprises at least 1 mole percent of monomeric repeat units of 3-hydroxypropionic acid ester.

[0077] Embodiment 2. The biodegradable aqueous mixture of Embodiment 1, wherein the first poly(hydroxyalkanoate) comprises at least 50 mole percent of monomeric repeat units of 3-hydroxypropionic acid ester, even more preferably 75 mole percent of monomeric repeat units of 3-hydroxypropionic acid ester.

[0078] Embodiment 2. The biodegradable aqueous mixture of Embodiment 1, wherein the first poly(hydroxyalkanoate) comprises poly(3-hydroxypropionic acid ester).

[0079] Embodiment 3. The biodegradable aqueous mixture of Embodiment 1 or 2, wherein the first poly(hydroxyalkanoate) is a copolymer or terpolymer comprising:

[0080] a first repeat unit that is (3-hydroxypropionic acid ester),

[0081] a second repeat unit according to Formula I

[0082]

[0083] optionally, a third repeat unit according to Formula II,

[0084]

[0085] wherein R1and R2are each independently selected from the group consisting of linear or branched alkyl groups having 1 to 22 carbon atoms.

[0086] Embodiment 4. The biodegradable aqueous mixture of Embodiment 3, wherein the first poly(hydroxyalkanoate) comprises a copolymer, R1is methyl.

[0087] Embodiment 5. The biodegradable aqueous mixture of Embodiment 4, wherein the poly(hydroxyalkanoate) copolymer comprises about 10 to about 90 mole percent of the first repeat unit and about 90 to about 10 mole percent of the second repeat unit.

[0088] Embodiment 6. The biodegradable aqueous mixture of Embodiment 3, wherein the first poly(hydroxyalkanoate) comprises a terpolymer, R1is methyl, and R2is propyl.

[0089] Embodiment 7. The biodegradable aqueous mixture of Embodiment 6, wherein the poly(hydroxyalkanoate) copolymer comprises about 15 to about 75 mole percent of the first repeat unit, about 75 to about 15 mole percent of the second repeat unit, and about 1 to about 5 mole percent of the third repeat unit.

[0090] Embodiment 8. The biodegradable aqueous mixture of any of the preceding embodiments, wherein the first poly(hydroxyalkanoate) has a weight average molecular weight of at least 50,000 Daltons as determined according to ASTM D4001-20.

[0091] Embodiment 9. The biodegradable aqueous mixture of any of the preceding embodiments, wherein the first poly(hydroxyalkanoate) has a weight average molecular weight of from about 50,000 to about 1,000,000 Daltons as determined according to ASTM D4001-20.

[0092] Embodiment 10. The biodegradable aqueous mixture of any of the preceding embodiments, wherein the solid further comprises a second poly(hydroxyalkanoate) that does not include monomeric repeat units of 3-hydroxypropionic acid ester.

[0093] Embodiment 11. The biodegradable aqueous mixture of any of the preceding embodiments, wherein the solid further comprises at least one biodegradable polymer selected from the group consisting of polybutylene succinate, polybutylene succinate-polybutylene adipate, polybutylene adipate-polybutylene terephthalate, polycaprolactone, polylactic acid, polyvinyl alcohol, polyglycolic acid, polyglycolic acid / polylactic acid copolymer, cellulose acetate, nanocellulose, isosorbide ester, and mixtures thereof.

[0094] Embodiment 12. The biodegradable aqueous mixture of any of the preceding embodiments, wherein the mixture further comprises from about 0.01 weight percent to about 5.0 weight percent of at least one surfactant selected from the group consisting of polysorbate, aromatic polyethylene oxide, sorbitan derivatives, block copolymers of polyethylene oxide and polypropylene oxide, polyethylene glycol ether, polyvinyl alcohol, alkyl sulfate salts, alkyl phosphate salts, stearate salts, and mixtures thereof.

[0095] Embodiment 13. The biodegradable aqueous mixture of any of the preceding embodiments, wherein the mixture further comprises from about 0.01 weight percent to about 5.0 weight percent of at least one rheology modifier selected from the group consisting of polysaccharides, acrylate-based emulsion copolymers, viscosity reducing agents, and viscosity increasing agents.

[0096] Embodiment 14. The biodegradable aqueous mixture of any of the preceding embodiments, wherein the mixture further comprises from about 0.01 weight percent to about 2.5 weight percent of at least one wetting and dispersing agent.

[0097] Embodiment 15. The biodegradable aqueous mixture of any of the preceding embodiments, wherein the mixture further comprises about 0.01 weight percent to about 0.5 weight percent of at least one biocide or biostat.

[0098] Embodiment 16. The biodegradable aqueous mixture of any of the preceding embodiments, wherein the mixture further comprises about 0.1 weight percent to about 5.0 weight percent of at least one coalescing agent selected from the group consisting of biomass succinic acid-based coalescing solvents, 2,2,4-trimethyl-l,3-pentanediol monoisobutyrate, dimethyl carbonate, methanol, ethanol, ketones, acetates, and / or mixtures thereof.

[0099] Embodiment 16. The biodegradable aqueous mixture of any of the preceding embodiments, wherein the mixture further comprises about 0.05 to about 1 weight percent of at least one defoaming agent selected from the group consisting of polyether siloxanes, polyamide particles, and mixtures thereof.

[0100] Embodiment 17. The biodegradable aqueous mixture of any of the preceding embodiments, wherein the mixture further comprises about 1 weight percent to about 35 weight percent of at least one filler selected from the group consisting of clay, calcium carbonate, talc, kaolinite, montmorillonite, bentonite, silica, chitin, titanium dioxide, nanoclay, or mixtures thereof.

[0101] Embodiment 18. The biodegradable aqueous mixture of any of the preceding embodiments, wherein the mixture comprises poly(hydroxyalkanoate) particles having a Dv(90) particle size of no more than about 20 microns, more preferably no more than about 10 microns, as determined using ISO 8130-13:201.

[0102] Embodiment 19. The biodegradable aqueous mixture of any of the preceding embodiments, wherein the mixture has an oxygen transmission rate of less than 50 cc / m2 / 24h, as determined according to ASTM D3985, when applied as a substrate coating. 2

[0103] Embodiment 20. The biodegradable aqueous mixture of any of the preceding embodiments, wherein the mixture has an oxygen transmission rate of 10 to 50 cc / m2 / 24h, as determined according to ASTM D3985, when applied as a substrate coating. 2

[0104] ​​Embodiment 21. The biodegradable aqueous mixture of any of the preceding embodiments, wherein the mixture has a water vapor transmission rate of less than 50 g / m 2 / 24h, according to ASTM F1249, when applied as a substrate coating.

[0105] Embodiment 22. The biodegradable aqueous mixture of any of the preceding embodiments, wherein the mixture has a water vapor transmission rate of 10 to 50 g / m 2 / 24h, according to ASTM F1249, when applied as a substrate coating.

[0106] Embodiment 23. A coated substrate, comprising:

[0107] a paperboard substrate having at least a first surface and a second surface; and

[0108] a coating on the at least first surface, wherein the coating is formed by applying the biodegradable aqueous mixture described above.

[0109] Embodiment 24. The coated substrate of Embodiment 23, wherein the coating is applied at a coating weight of about 20 to about 40 g / m 2 , as determined according to ASTM F2217.

[0110] The foregoing description of preferred embodiments of the application has been presented for the purposes of illustration and description. They are not intended to be exhaustive or to limit the application to the precise form disclosed. Obvious modifications or variations are possible in light of the above teachings. The implementation outlined and described is not intended to be exhaustive or to be made to the precise form disclosed. Many modifications and variations are possible in light of the above teaching. The implementation described is chosen and described in order to provide the best illustration of the principles of the application and its practical application to thereby enable one of ordinary skill in the art to utilize the application in various embodiments and with various modifications as are suited to the particular use contemplated.

Claims

1. A biodegradable aqueous mixture for coating a substrate, the mixture comprising: 35 to 75 weight percent water and 25 to 65 weight percent solids, wherein the solids comprise, based on the total dry weight of the solids, 40 to 99 weight percent of a first poly(hydroxyalkanoate), and wherein the first poly(hydroxyalkanoate) comprises at least 1 mole percent of monomeric repeat units of 3-hydroxypropionate ester; wherein the first poly(hydroxyalkanoate) is a terpolymer, the first poly(hydroxyalkanoate) comprising: a first repeat unit of (3-hydroxypropionate ester), a second repeat unit according to Formula I a third repeat unit according to Formula II, wherein R1 is methyl and R2 is propyl.

2. The biodegradable aqueous mixture of claim 1, wherein the poly(hydroxyalkanoate) copolymer comprises 15 to 75 mole percent of the first repeat unit, 75 to 15 mole percent of the second repeat unit, and 1 to 5 mole percent of the third repeat unit.

3. The biodegradable aqueous mixture of claim 1, wherein the first poly(hydroxyalkanoate) has a weight average molecular weight of at least 50,000 Daltons as determined according to ASTM D4001-20.

4. The biodegradable aqueous mixture of claim 1, wherein the first poly(hydroxyalkanoate) has a weight average molecular weight of 50,000 to 1,000,000 Daltons as determined according to ASTM D4001-20.

5. The biodegradable aqueous mixture of claim 1, wherein the solids further comprise a second poly(hydroxyalkanoate) that does not comprise 3-hydroxypropionate ester monomeric repeat units.

6. The biodegradable aqueous mixture of claim 1, wherein the solids further comprise at least one biodegradable polymer selected from the group consisting of polybutylene succinate, polybutylene succinate-polybutylene adipate, polybutylene adipate-polybutylene terephthalate, polycaprolactone, polylactic acid, polyvinyl alcohol, polyglycolic acid, polyglycolic acid / polylactic acid copolymer, cellulose acetate, nanocellulose, isosorbide esters, and mixtures thereof.

7. The biodegradable aqueous mixture of claim 1, wherein the mixture further comprises 0.01 to 5.0 weight percent of at least one surfactant selected from the group consisting of polysorbates, aromatic polyethylene oxides, sorbitan derivatives, block copolymers of polyethylene oxide and polypropylene oxide, polyethylene glycol ethers, polyvinyl alcohol, alkyl sulfates, alkyl phosphates, stearates, and mixtures thereof.

8. The biodegradable aqueous mixture of claim 1, wherein the mixture further comprises 0.01 to 5.0 weight percent of at least one rheology modifier selected from the group consisting of polysaccharides, acrylate-based emulsion copolymers, viscosity depressants, and viscosity enhancers.

9. The biodegradable aqueous mixture of claim 1, wherein the mixture further comprises 0.01 to 2.5 weight percent of at least one wetting and dispersing agent.

10. The biodegradable aqueous mixture of claim 1, wherein the mixture further comprises 0.01 to 0.5 weight percent of at least one biocide or biostat.

11. The biodegradable aqueous mixture of claim 1, wherein the mixture further comprises 0.1 to 5.0 weight percent of at least one coalescing agent selected from the group consisting of biomass succinic acid based coalescing solvents, 2,2,4-trimethyl-l,3-pentanediol monoisobutyrate, dimethyl carbonate, methanol, ethanol, ketones, acetates, and / or mixtures thereof.

12. The biodegradable aqueous mixture of claim 1, wherein the mixture further comprises 1 to 35 weight percent of at least one filler selected from the group consisting of clays, calcium carbonate, talc, kaolinite, montmorillonite, bentonite, silica, chitin, titanium dioxide, nanoclays, or mixtures thereof.

13. The biodegradable aqueous mixture of claim 1, wherein the mixture comprises poly(hydroxyalkanoate) particles having a Dv(90) particle size of no more than 20 microns as determined according to ISO 8130-13:

201.

14. The biodegradable aqueous mixture of claim 1, wherein the mixture has an oxygen transmission rate of less than 50 cc / m2 / 24h when applied as a base coating, as determined according to ASTM D3985. 2 / 24h of oxygen transmission rate.

15. The biodegradable aqueous mixture of claim 1, wherein when applied as a substrate coating, the mixture has a concentration of 10 to 50 cc / m³ as determined according to ASTM D3985. 2 / 24h oxygen permeation rate.

16. The biodegradable aqueous mixture of claim 1, wherein the mixture has a water vapor transmission rate of less than 50 g / m2 / 24h according to ASTM F1249 when applied as a base coating. 2 / 24h.

17. The biodegradable aqueous mixture of claim 1, wherein the mixture has a water vapor transmission rate of 10 to 50 g / m 2 / 24h according to ASTM F1249 when applied as a base coating.

18. A coated substrate comprising: a paperboard substrate having at least a first surface and a second surface; and a coating on the at least first surface, wherein the coating is formed by applying the biodegradable aqueous mixture of claim 1.

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