Aqueous mixtures of novel poly (hydroxyalkanoates)

Abstract

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

Description

Technical Field

[0001] The present invention relates to biodegradable polymer compositions. More particularly, the present invention relates to biodegradable coatings for paperboard substrates and the like made from aqueous mixtures of poly(hydroxyalkanoates) ("PHAs"). Background Art

[0002] Disposable items, such as food service items, can be easily and conveniently manufactured from substrates such as paperboard, which decompose relatively quickly after disposal in landfills. However, plain, uncoated paperboard substrates generally perform poorly because the paperboard quickly absorbs water and / or grease, which affects the strength of the paperboard. Therefore, paperboard-based products are often coated with a thin polymer layer to improve water and grease resistance.

[0003] Coatings made of polymers such as polyethylene (PE), polypropylene (PP) or polyethylene terephthalate (PET) can significantly increase paperboard's resistance to water and / or grease absorption; however, such polymers do not readily degrade or break down after landfill disposal. As a result, paperboard items coated with such polymers can remain in landfills for centuries after disposal.

[0004] Therefore, it is desirable to provide a novel fully biodegradable coating for substrates, such as food service articles. In addition, it is desirable that such a biodegradable coating has good water and grease resistance, i.e., water and grease resistance comparable to conventional non-biodegradable coatings.

[0005] Additionally, there is 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 rate and water vapor transmission rate. There is also a need to provide a substrate coated with such a material. Summary of the invention

[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, the aqueous mixture consists of about 35 to about 75 weight percent water and about 25 to about 65 weight percent solids. The solids are composed of about 40 to about 99 weight percent of the first poly (hydroxyalkanoate) based on the total dry weight of the solids.

[0007] This first poly(hydroxyalkanoate) consists of at least 1 mole percent of monomeric repeating units of 3-hydroxypropionate. Preferably, the first poly(hydroxyalkanoate) consists of at least 50 mole percent of monomeric repeating units of 3-hydroxypropionate, and even more preferably, 75 mole percent of monomeric repeating 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 a terpolymer. This copolymer or terpolymer consists of the following components:

[0010] The first repeating unit is (3-hydroxypropionate),

[0011] The second repeating unit according to formula I

[0012]

[0013] Optionally, according to the third repeating unit of formula II,

[0014]

[0015] wherein R1 and R2 are each independently selected from the group consisting of a linear or branched alkyl group having 1 to 22 carbon atoms.

[0016] In some embodiments, the first poly(hydroxyalkanoate) is preferably a copolymer, and R1 is methyl. In some cases, the poly(hydroxyalkanoate) copolymer preferably consists of about 10 to about 90 mole percent of the first repeating unit and about 90 to about 10 mole percent of the second repeating unit. More preferably, the poly(hydroxyalkanoate) copolymer consists of about 30 to about 70 mole percent of the first repeating unit and about 70 to about 30 mole percent of the second repeating unit.

[0017] In other embodiments, the first poly(hydroxyalkanoate) is preferably a terpolymer, wherein R1 is methyl and R2 is propyl. In some cases, the poly(hydroxyalkanoate) terpolymer preferably consists of about 15 to about 75 mole percent of the first repeating unit, about 75 to about 15 mole percent of the second repeating unit, and about 1 to about 5 mole percent of the third repeating unit. More preferably, the terpolymer preferably consists of about 30 to about 60 mole percent of the first repeating unit, about 60 to about 30 mole percent of the second repeating unit, and about 1 to about 5 mole percent of the third repeating unit.

[0018] According to certain embodiments, the first poly(hydroxyalkanoate) preferably has a weight average molecular weight of at least 50,000 Daltons as measured by 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 as measured by ASTM D4001-20.

[0019] In some embodiments, the solids of the aqueous mixture according to the present invention may include a second poly(hydroxyalkanoate) and the first poly(hydroxyalkanoate). This second poly(hydroxyalkanoate) does not include monomer repeating units of 3-hydroxypropionate.

[0020] In other embodiments, the solid of the aqueous mixture may also include 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, and mixtures thereof.

[0021] In some embodiments, the mixture preferably further comprises 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, polyethylene glycol ethers, polyvinyl alcohol, alkyl sulfates, alkyl phosphates, stearates, and mixtures thereof.

[0022] According to certain embodiments, the mixture preferably further comprises 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 reducers, and viscosity increasers.

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

[0024] 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.

[0025] In certain embodiments, the mixture preferably 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-1,3-pentanediol monoisobutyrate, dimethyl carbonate, methanol, ethanol, ketones, acetates, and / or mixtures thereof.

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

[0027] In some embodiments, the mixture preferably 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.

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

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

[0030] In certain embodiments, when applied as a substrate coating, the mixture has a relative humidity of less than 50 g / m 2 In some cases, when applied as a substrate coating, the mixture has a water vapor transmission rate of 10 to 50 g / m2 according to ASTM F1249. 2 / 24h water vapor transmission rate.

[0031] In another aspect, the present invention also provides a coated substrate. The 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 invention provides a biodegradable aqueous mixture for coating a substrate. Typically, the aqueous mixture may be in the form of a suspension, emulsion or colloid.

[0033] As used herein, "suspension" refers to a heterogeneous mixture of at least two substances (dispersed material and 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 gravity than certain other mixtures (e.g., colloids).

[0034] As used herein, a "colloid" is a heterogeneous mixture with a particle size between that of 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 (eg, a surfactant) is present.

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

[0037] The solids of the mixture, accordingly, include at least a poly(hydroxyalkanoate), and may also include other biopolymers and / or additives. Typically, the solids include from 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 from about 40 to about 50 weight percent of the first poly(hydroxyalkanoate), based on the total dry weight of the solids.

[0038] Importantly, the first poly(hydroxyalkanoate) is composed of at least 1 mole percent of monomer repeating units of 3-hydroxypropionate. Preferably, the first poly(hydroxyalkanoate) is composed of at least 50 mole percent of monomer repeating units of 3-hydroxypropionate, and even more preferably, 75 mole percent of monomer repeating units of 3-hydroxypropionate.

[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, ie, poly(3-hydroxypropionate).

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

[0041] The first repeating unit is (3-hydroxypropionate),

[0042] The second repeating unit according to formula I

[0043]

[0044] Optionally, according to the third repeating unit of formula II,

[0045]

[0046] wherein R1 and R2 are each independently selected from the group consisting of a linear or branched alkyl group having 1 to 22 carbon atoms.

[0047] In some embodiments, the poly(hydroxyalkanoate) is more preferably a copolymer and R1 is methyl. In these embodiments, the poly(hydroxyalkanoate) copolymer is generally composed of about 10 to about 90 mole percent of the first repeating unit and about 90 to about 10 mole percent of the second repeating unit. More preferably, the poly(hydroxyalkanoate) copolymer is composed of about 30 to about 70 mole percent of the first repeating unit and about 70 to about 30 mole percent of the second repeating unit.

[0048] In other embodiments, the poly(hydroxyalkanoate) is more preferably a terpolymer, wherein R1 is methyl and R2 is propyl. In these embodiments, the poly(hydroxyalkanoate) terpolymer is generally composed of about 15 to about 75 mole percent of the first repeating unit, about 75 to about 15 mole percent of the second repeating unit, and about 1 to about 5 mole percent of the third repeating unit. More preferably, the terpolymer is preferably composed of about 30 to about 60 mole percent of the first repeating unit, about 60 to about 30 mole percent of the second repeating unit, and about 1 to about 5 mole percent of the third repeating unit.

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

[0050] Although the first poly(hydroxyalkanoate) can be prepared by fermentation in a bioreactor, in some embodiments, the first poly(hydroxyalkanoate) is preferably prepared by ring-opening polymerization of substituted lactones. For example, the repeating unit of the 3-hydroxypropionate can be formed by ring-opening polymerization of β-propiolactone.

[0051] When synthesized in this manner, it has been found that the first poly(hydroxyalkanoate) particles so formed are generally 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 measured using ISO 8130-13:201.

[0052] In some cases, 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 monomer repeat units of 3-hydroxypropionate. 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 solid of described aqueous mixture can also comprise at least one biodegradable polymer, described polymer is selected from the group of free 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, nano cellulose, isosorbide, and composition thereof.In a preferred embodiment, described solid can comprise PBSA and / or PBAT.When existing, extra biopolymer forms solid about 1 to about 50 weight percent usually.

[0054] As mentioned above, in addition to the above-mentioned biopolymers, the mixture may also include various additives.

[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, polyethylene glycol ethers, polyvinyl alcohol, alkyl sulfates, alkyl phosphates, stearates, and mixtures thereof.

[0056] In certain embodiments, the mixture may further 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 reducers, and viscosity enhancers.

[0057] The mixture may 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-functional additive that provides wetting and dispersing functions to 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] In addition, in certain embodiments, the mixture may also include 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-1,3-pentanediol monoisobutyrate, dimethyl carbonate, methanol, ethanol, ketones, acetates, and / or mixtures thereof.

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

[0061] In some embodiments, the mixture preferably 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.

[0062] The mixture of the present invention can be prepared by mixing 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 (e.g., a Silverson mixer). Alternatively, the components of the mixture can be mixed in a pressurized vessel, such as a Parr reactor.

[0063] The present invention 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-mentioned 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, when applied as a substrate coating, the mixture preferably has a relative humidity of less than 50 cc / m 2 In some cases, when applied as a substrate coating, the mixture has an oxygen transmission rate of 10 to 50 cc / m / 24h as measured according to ASTM D3985. 2 / 24h oxygen transmission rate.

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

[0066] In another aspect, the present invention also provides a coated substrate. The 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.

[0067] The aqueous mixture is typically applied using rod, gravure, 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 about 5 to about 20 g / m2 as measured by ASTM F2217. 2 This is a relatively low coating weight for a biodegradable coating. Coatings formed from biodegradable polymers more typically have a coating weight of about 20 to about 40 g / m 2 of coating weight applied.

[0069] Despite these relatively low coating weights, the coatings of the present invention have been found to provide excellent barrier properties.

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

[0071] Regarding water vapor transmission rate, when applied as a substrate coating, the mixture has a water vapor transmission rate of less than 50 g / m according to ASTM F1249. 2 In some cases, when applied as a substrate coating, the mixture has a water vapor transmission rate of 10 to 50 g / m2 according to ASTM F1249. 2 / 24h water vapor transmission rate.

[0072] The present invention is further described 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 solid comprises from about 40 to about 99 weight percent of the first poly(hydroxyalkanoate), based on the total dry weight of the solid, and

[0076] Wherein, the first poly(hydroxyalkanoate) comprises at least 1 mole percent of monomer repeating units of 3-hydroxypropionate.

[0077] Embodiment 2. The biodegradable aqueous mixture of embodiment 1, wherein the first poly(hydroxyalkanoate) comprises at least 50 mole percent of monomer repeating units of 3-hydroxypropionate, and even more preferably 75 mole percent of monomer repeating units of 3-hydroxypropionate.

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

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

[0080] The first repeating unit is (3-hydroxypropionate),

[0081] The second repeating unit according to formula I

[0082]

[0083] Optionally, according to the third repeating unit of formula II,

[0084]

[0085] wherein R1 and R2 are each independently selected from the group consisting of a linear or branched alkyl group having 1 to 22 carbon atoms.

[0086] Embodiment 4. The biodegradable aqueous mixture of embodiment 3, wherein the first poly(hydroxyalkanoate) comprises a copolymer and R1 is 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 repeating unit and about 90 to about 10 mole percent of the second repeating unit.

[0088] Embodiment 6. The biodegradable aqueous mixture of embodiment 3, wherein the first poly(hydroxyalkanoate) comprises a terpolymer, R1 is methyl, and R2 is 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 repeating unit, about 75 to about 15 mole percent of the second repeating unit, and about 1 to about 5 mole percent of the third repeating 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 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 repeating units of 3-hydroxypropionate.

[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 copolymers, cellulose acetate, nanocellulose, isosorbide, 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 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.

[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 reducers, and viscosity increasers.

[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 from 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, the coalescing agent being 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.

[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 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.

[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 measured using ISO 8130-13:201.

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

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

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

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

[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 above-mentioned biodegradable aqueous mixture.

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

[0110] For the purpose of illustration and description, the present invention has been given the above description of preferred embodiments. They are not intended to be exhaustive or to limit the invention to the precise form disclosed. Obvious modifications or changes can be made based on the above teachings. The embodiments are selected and described in order to provide the best description of the principles of the present invention and its practical application, so that those of ordinary skill in the art can utilize the present invention in various embodiments and make various modifications to suit the intended specific use.

Claims

1. A biodegradable aqueous mixture for coating a substrate, the mixture comprising: about 35 to about 75 weight percent water and about 25 to about 65 weight percent solids, wherein the solid comprises from about 40 to about 99 weight percent of the first poly(hydroxyalkanoate), based on the total dry weight of the solid, and Wherein, the first poly(hydroxyalkanoate) comprises at least 1 mole percent of monomer repeating units of 3-hydroxypropionate.

2. The biodegradable aqueous mixture of claim 1, wherein the first poly(hydroxyalkanoate) comprises poly(3-hydroxypropionate).

3. The biodegradable aqueous mixture of claim 1, wherein the first poly(hydroxyalkanoate) is a copolymer or terpolymer comprising: The first repeating unit is (3-hydroxypropionate), The second repeating unit according to formula I Optionally, according to the third repeating unit of formula II, wherein R1 and R2 are each independently selected from the group consisting of a linear or branched alkyl group having 1 to 22 carbon atoms.

4. The biodegradable aqueous mixture of claim 3, wherein the first poly(hydroxyalkanoate) comprises a copolymer and R1 is methyl.

5. The biodegradable aqueous mixture of claim 4, wherein the poly(hydroxyalkanoate) copolymer comprises from about 10 to about 90 mole percent of the first repeating unit and from about 90 to about 10 mole percent of the second repeating unit.

6. The biodegradable aqueous mixture of claim 3, wherein the first poly(hydroxyalkanoate) comprises a terpolymer, R1 is methyl, and R2 is propyl.

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

8. 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.

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

10. The biodegradable aqueous mixture of claim 1, wherein the solid further comprises a second poly(hydroxyalkanoate) that does not include monomer repeating units of 3-hydroxypropionate.

11. The biodegradable aqueous mixture according to claim 1, 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, and mixtures thereof.

12. The biodegradable aqueous mixture of claim 1, 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 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.

13. The biodegradable aqueous mixture of claim 1, 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 reducers, and viscosity increasers.

14. The biodegradable aqueous mixture of claim 1, 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.

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

16. The biodegradable aqueous mixture of claim 1, 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-1,3-pentanediol monoisobutyrate, dimethyl carbonate, methanol, ethanol, ketones, acetates, and / or mixtures thereof.

17. The biodegradable aqueous mixture of claim 1, 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.

18. The biodegradable aqueous mixture of claim 1, wherein the mixture comprises poly(hydroxyalkanoate) particles having a Dv(90) particle size of no greater than about 20 microns, more preferably no greater than about 10 microns, as determined using ISO 8130-13:

201.

19. The biodegradable aqueous mixture of claim 1, wherein when applied as a coating on a substrate, the mixture has a relative humidity of less than 50 cc / m2 as measured according to ASTM D3985. 2 / 24h oxygen transmission rate.

20. The biodegradable aqueous mixture of claim 1, wherein when applied as a substrate coating, the mixture has a relative humidity of 10 to 50 cc / m 2 / 24h oxygen transmission rate.

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

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

23. 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 above-mentioned biodegradable aqueous mixture.

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