Aqueous blends 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 about 40 to about 99 weight percent, based on the total dry weight of the solids, of a first poly(hydroxyalkanoate), the first poly(hydroxyalkanoate) being composed of at least 1 mole percent 3-hydroxypropionate monomer repeat units.

Description

[Technical Field]

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

[0002] Disposable articles, such as food service items, can be advantageously manufactured from substrates such as paperboard, which decompose relatively quickly after being disposed of in a landfill. However, simple, uncoated paperboard substrates often perform poorly because they rapidly absorb water and / or grease, which impairs the strength of the paperboard. Therefore, paperboard-based articles are typically coated with a thin layer of polymer to improve water and grease resistance.

[0003] Coatings made from polymers such as polyethylene (PE), polypropylene (PP), or poly(ethylene terephthalate) (PET) can significantly improve paperboard's resistance to water and / or grease absorption. However, these polymers do not readily decompose or decay after being disposed of in a landfill. That is, paperboard products coated with these polymers may remain in landfills for years after disposal.

[0004] Thus, it would be desirable to provide a new coating for substrates such as food service utensils that is completely biodegradable. Moreover, it would be desirable if the biodegradable coating could provide good water and grease resistance, i.e., water and grease resistance comparable to that of conventional, non-biodegradable coatings.

[0005] Still further, it would be desirable to provide biodegradable coatings that can be applied to substrates at relatively low coating weights and still provide barrier properties, such as low oxygen and water vapor transmission rates. It would also be desirable to provide substrates coated with such materials. Summary of the Invention

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

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

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

[0009] In another embodiment, the first poly(hydroxyalkanoate) in the aqueous mixture is preferably a copolymer or terpolymer. The copolymer or terpolymer may be:

[0010] a first repeat unit which is (3-hydroxypropionate);

[0011] a second repeat unit according to formula I; [ka] and

[0012] optionally a third repeat unit according to formula II; [ka] It consists of

[0013] In the formula, R1 and R2 are each independently selected from the group consisting of straight or branched chain alkyl groups having 1 to 22 carbon atoms.

[0014] In some embodiments, the first poly(hydroxyalkanoate) is preferably a copolymer, and R1 is methyl. In some examples, the poly(hydroxyalkanoate) copolymer is preferably composed of about 10 to about 90 mole percent of the first repeating units and about 90 to about 10 mole percent of the second repeating units. More preferably, the poly(hydroxyalkanoate) copolymer is composed of about 30 to about 70 mole percent of the first repeating units and about 70 to about 30 mole percent of the second repeating units.

[0015] In other embodiments, the first poly(hydroxyalkanoate) is preferably a terpolymer, where R1 is methyl and R2 is propyl. In some examples, the poly(hydroxyalkanoate) terpolymer is preferably composed of about 15 to about 75 mole percent of the first repeating units, about 75 to about 15 mole percent of the second repeating units, and about 1 to about 5 mole percent of the third repeating units. More preferably, the terpolymer is preferably composed of about 30 to about 60 mole percent of the first repeating units, about 60 to about 30 mole percent of the second repeating units, and about 1 to about 5 mole percent of the third repeating units.

[0016] According to certain embodiments, the first poly(hydroxyalkanoate) preferably has a weight average molecular weight of at least 50,000 daltons as specified by ASTM D4001-20. More preferably, the first poly(hydroxyalkanoate) has a weight average molecular weight of from about 50,000 to about 1,000,000 daltons as specified by ASTM D4001-20.

[0017] In some embodiments, the solids of the aqueous mixture according to the present disclosure can include a second poly(hydroxyalkanoate) along with the first poly(hydroxyalkanoate), where the second poly(hydroxyalkanoate) does not include 3-hydroxypropionate monomer repeat units.

[0018] In other embodiments, the solids of the aqueous mixture can also include at least one biodegradable polymer selected from the group consisting of polybutylene succinate, polybutylene succinate-co-butylene adipate, polybutylene adipate-co-butylene terephthalate, polycaprolactone, polylactic acid, poly(vinyl alcohol), polyglycolic acid, polyglycolic acid / polylactic acid copolymer, cellulose acetate, nanocellulose, isosorbide esters, and mixtures thereof.

[0019] In some embodiments, the mixture also preferably 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 poly(ethylene oxide) and poly(propylene oxide), poly(glycol ethers), poly(vinyl alcohols), alkyl sulfates, alkyl phosphates, stearates, and mixtures thereof.

[0020] According to certain embodiments, the mixture also preferably includes from about 0.01 weight percent to about 5.0 weight percent of at least one rheology modifier, the rheology modifier being selected from the group consisting of polysaccharides, acrylate-based emulsion copolymers, viscosity reducers, and thickeners.

[0021] In some cases, the mixture also preferably includes from about 0.01 weight percent to about 2.5 weight percent of at least one wetting and dispersing agent.

[0022] According to certain embodiments, the mixture also preferably includes from about 0.01 weight percent to about 0.5 weight percent of at least one biocide or bacteriostat.

[0023] In certain embodiments, the mixture also preferably includes from about 0.1 weight percent to about 5.0 weight percent of at least one coalescing agent selected from the group consisting of biosuccinic acid-based coalescing solvent, 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate, dimethyl carbonate, methanol, ethanol, ketones, acetates, and / or mixtures thereof.

[0024] In some embodiments, the mixture also preferably comprises from about 0.05 to about 1 weight percent of at least one antifoaming agent selected from the group consisting of polyether siloxanes, polyamide particles, and mixtures thereof.

[0025] In some embodiments, the mixture also preferably comprises from about 1 weight percent to about 35 weight percent of at least one bulking agent, the bulking agent being selected from the group consisting of clay, calcium carbonate, talc, kaolinite, montmorillonite, bentonite, silica, chitin, titanium dioxide, nanoclay, or mixtures thereof.

[0026] In certain embodiments, the mixture comprises poly(hydroxyalkanoate) particles having a Dv(90) particle size of about 20 microns or less, more preferably about 10 microns or less, as determined using ISO 8130-13:201.

[0027] According to one particular embodiment, the mixture, when applied as a substrate coating, preferably has an oxygen transmission rate of 50 cc / m as determined in accordance with ASTM D3985. 2 In some instances, the mixture, when applied as a substrate coating, has an oxygen transmission rate of 10 to 50 cc / m2 as determined in accordance with ASTM D3985. 2 / 24h.

[0028] In certain embodiments, the mixture, when applied as a substrate coating, has a water vapor transmission rate of 50 g / m according to ASTM F1249. 2 In some instances, the mixture, when applied as a substrate coating, has a water vapor transmission rate of 10 to 50 g / m² according to ASTM F1249. 2 / 24h.

[0029] In a further aspect, the present disclosure also provides a coated substrate comprising a paperboard substrate having at least a first surface and a second surface, and a coating layer over at least the first surface, the coating being formed by applying the biodegradable aqueous mixture described above. DETAILED DESCRIPTION OF THE INVENTION

[0030] Again, the present disclosure provides a biodegradable aqueous mixture for coating a substrate. Generally, the aqueous mixture can be in the form of either a suspension, an emulsion, or a colloid.

[0031] As used in this context, 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 will also have a higher tendency to settle under the influence of gravity compared to certain other mixtures, such as colloids.

[0032] As used herein, a "colloid" is a heterogeneous mixture whose particle size is intermediate between that of a solution and that of a suspension. The dispersed particles are evenly dispersed throughout the dispersion medium, i.e., liquid water. Particles present in colloids exhibit a light scattering effect known as the Tyndall effect.

[0033] As used herein, an "emulsion" is a type of colloid when an emulsifying agent (eg, a surfactant) is present.

[0034] 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 instances, the mixture more preferably includes about 45 to about 55 weight percent water and about 45 to about 55 weight percent solids.

[0035] The solids of the mixture then comprise at least a poly(hydroxyalkanoate) and may also comprise other biopolymers and / or additives. Typically, the solids comprise 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 comprise from about 40 to about 50 weight percent of the first poly(hydroxyalkanoate), based on the total dry weight of the solids.

[0036] Importantly, the first poly(hydroxyalkanoate) is comprised of at least 1 mole percent 3-hydroxypropionate monomer repeat units. Preferably, the first poly(hydroxyalkanoate) is comprised of at least 50 mole percent 3-hydroxypropionate monomer repeat units, and even more preferably, at least 75 mole percent 3-hydroxypropionate monomer repeat units.

[0037] In general, the first poly(hydroxyalkanoate) of the composition can be a homopolymer, copolymer, or terpolymer, i.e., in certain embodiments, the first poly(hydroxyalkanoate) is a homopolymer, also known as poly(3-hydroxypropionate).

[0038] In other embodiments, the poly(hydroxyalkanoate) is a copolymer or terpolymer,

[0039] a first repeat unit which is (3-hydroxypropionate);

[0040] a second repeat unit according to formula I; [ka] and

[0041] optionally a third repeat unit according to formula II; [ka] It consists of

[0042] In the formula, R1 and R2 are each independently selected from the group consisting of straight or branched chain alkyl groups having 1 to 22 carbon atoms.

[0043] In some embodiments, the poly(hydroxyalkanoate) is more preferably a copolymer, and R1 is methyl. In such embodiments, the poly(hydroxyalkanoate) copolymer generally comprises from about 10 to about 90 mole percent of the first repeating units and from about 90 to about 10 mole percent of the second repeating units. More preferably, the poly(hydroxyalkanoate) copolymer comprises from about 30 to about 70 mole percent of the first repeating units and from about 70 to about 30 mole percent of the second repeating units.

[0044] In other embodiments, the poly(hydroxyalkanoate) is more preferably a terpolymer, where R1 is methyl and R2 is propyl. In such embodiments, the poly(hydroxyalkanoate) terpolymer generally comprises from about 15 to about 75 mole percent of the first repeating units, from about 75 to about 15 mole percent of the second repeating units, and from about 1 to about 5 mole percent of the third repeating units. More preferably, the terpolymer comprises from about 30 to about 60 mole percent of the first repeating units, from about 60 to about 30 mole percent of the second repeating units, and from about 1 to about 5 mole percent of the third repeating units.

[0045] The first poly(hydroxyalkanoate) typically has a weight average molecular weight of at least 50,000 daltons as measured in accordance with ASTM D4001-20. More preferably, the first poly(hydroxyalkanoate) has a weight average molecular weight of from about 50,000 to about 1,000,000 daltons as determined in accordance with ASTM D4001-20.

[0046] Although the first poly(hydroxyalkanoate) can be prepared by fermentation in a bioreactor, in some embodiments the first poly(hydroxyalkanoate) is preferably prepared synthetically via ring-opening polymerization of a substituted lactone. For example, 3-hydroxypropionate repeat units can be formed from the ring-opening polymerization of beta-propiolactone.

[0047] When synthesized in this manner, it has been found that the particles of the first poly(hydroxyalkanoate) so formed are typically smaller in size than particles of poly(hydroxyalkanoate) formed via biofermentation. In some embodiments, the mixture comprises particles of the first poly(hydroxyalkanoate) having a Dv(90) particle size of about 20 microns or less, more preferably about 10 microns or less, as determined using ISO 8130-13:201.

[0048] In some 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 3-hydroxypropionate monomer repeat units. For example, the second poly(hydroxyalkanoate) can include poly(hydroxybutyrate) or poly-3-hydroxybutyrate-co-3-hydroxyhexanoate ("P(3HB-co-3HHx)"). When present, the second poly(hydroxyalkanoate) typically comprises from about 1 to about 50 weight percent of the solids.

[0049] Additionally, the solids of the aqueous mixture can also include at least one biodegradable polymer selected from the group consisting of polybutylene succinate, polybutylene succinate-co-butylene adipate ("PBSA"), polybutylene adipate-co-butylene terephthalate ("PBAT"), polycaprolactone, polylactic acid, poly(vinyl alcohol), polyglycolic acid, polyglycolic acid / polylactic acid copolymer, cellulose acetate, nanocellulose, isosorbide esters, 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.

[0050] As noted above, the mixture may also include various additives in addition to the aforementioned biopolymers.

[0051] For example, in some embodiments, the mixture can include 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 poly(ethylene oxide) and poly(propylene oxide), poly(glycol ethers), poly(vinyl alcohols), alkyl sulfates, alkyl phosphates, stearates, and mixtures thereof.

[0052] In certain embodiments, the mixture also contains 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 thickeners.

[0053] The mixture may also include from about 0.01 weight percent to about 2.5 weight percent of at least one wetting and dispersing agent, i.e., a bifunctional additive that provides both wetting and dispersing functions to the solids in the mixture. Examples of suitable wetting and dispersing agents include polysorbates, polyesters, ethoxylates, and amphiphilic chemicals.

[0054] According to certain embodiments, the mixture also preferably includes from about 0.01 weight percent to about 0.5 weight percent of at least one biocide or bacteriostat.

[0055] Moreover, in certain embodiments, the mixture can also include from 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 biosuccinic acid-based coalescing solvent, 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate, dimethyl carbonate, methanol, ethanol, ketones, acetates, and / or mixtures thereof.

[0056] In some embodiments, the mixture also preferably includes from about 0.05 to about 1 weight percent of at least one antifoaming agent, the antifoaming agent being selected from the group consisting of polyether siloxanes, polyamide particles, and mixtures thereof.

[0057] In some embodiments, the mixture also contains from about 1 weight percent to about 35 weight percent of at least one bulking agent, preferably selected from the group consisting of clay, calcium carbonate, talc, kaolinite, montmorillonite, bentonite, silica, chitin, titanium dioxide, nanoclay, or mixtures thereof.

[0058] The mixtures of the present disclosure can be prepared by combining water, a first polyhydroxyalkanoate, an optional second polyhydroxyalkanoate, and optional 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.

[0059] The present disclosure 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 biodegradable aqueous mixture is applied to at least the first surface of the substrate. In some instances, both the first and second surfaces of the substrate are coated.

[0060] According to one particular embodiment, the mixture, when applied as a substrate coating, preferably has an oxygen transmission rate of 50 cc / m as determined in accordance with ASTM D3985. 2 In some instances, the mixture, when applied as a substrate coating, has an oxygen transmission rate of 10 to 50 cc / m2 as determined in accordance with ASTM D3985. 2 / 24h.

[0061] In certain embodiments, the mixture, when applied as a substrate coating, has a water vapor transmission rate of 50 g / m according to ASTM F1249. 2 In some instances, the mixture, when applied as a substrate coating, has a water vapor transmission rate of 10 to 50 g / m² according to ASTM F1249. 2 / 24h.

[0062] In a further aspect, the present disclosure also provides a coated substrate comprising a paperboard substrate having at least a first surface and a second surface, and a coating layer over at least the first surface, the coating being formed by application of the biodegradable aqueous mixture described above.

[0063] The aqueous mixture is typically applied using rod, gravure, or air knife coating techniques and then dried to provide a solid coating on the substrate.

[0064] Once dried and hardened, the coating weight is typically about 5 to about 20 g / m as specified 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 as specified by ASTM F2117. 2 It is applied with a coating amount of

[0065] Despite these relatively low coating weights, the coatings of the present invention have been found to provide excellent barrier property performance.

[0066] As noted above, the mixture, when applied as a substrate coating, preferably has an oxygen transmission rate of 50 cc / m as determined in accordance with ASTM D3985. 2 In some instances, the mixture, when applied as a substrate coating, has an oxygen transmission rate of 10 to 50 cc / m2 as determined in accordance with ASTM D3985. 2 / 24h.

[0067] With regard to water vapor permeability, the mixture, when applied as a substrate coating, has a water vapor transmission rate of 50 g / m according to ASTM F1249. 2 In some instances, the mixture, when applied as a substrate coating, has a water vapor transmission rate of 10 to 50 cc / m according to ASTM F1249. 2 / 24h.

[0068] The present disclosure is further illustrated by the following embodiments:

[0069] Embodiment 1. A biodegradable aqueous mixture for coating a substrate, said mixture comprising:

[0070] about 35 to about 75 weight percent water, and about 25 to about 65 weight percent solids;

[0071] the solids comprising from about 40 to about 99 weight percent of the first poly(hydroxyalkanoate), based on the total dry weight of the solids; and

[0072] the first poly(hydroxyalkanoate) comprises at least 1 mole percent 3-hydroxypropionate monomer repeat units; The mixture.

[0073] Embodiment 2. The biodegradable aqueous mixture of embodiment 1, wherein the first poly(hydroxyalkanoate) comprises at least 50 mole percent 3-hydroxypropionate monomer repeat units, and even more preferably comprises at least 75 mole percent 3-hydroxypropionate monomer repeat units.

[0074] Embodiment 2. The biodegradable aqueous mixture of embodiment 1, wherein the first poly(hydroxyalkanoate) comprises poly(3-hydroxypropionate).

[0075] Embodiment 3. The first poly(hydroxyalkanoate) is a copolymer or terpolymer comprising:

[0076] a first repeat unit which is (3-hydroxypropionate);

[0077] a second repeat unit according to formula I; [ka] and

[0078] optionally a third repeat unit according to formula II; [ka] Including,

[0079] wherein R1 and R2 are each independently selected from the group consisting of linear or branched alkyl groups having 1 to 22 carbon atoms; 3. The biodegradable aqueous mixture of embodiment 1 or 2.

[0080] Embodiment 4. The biodegradable aqueous mixture of embodiment 3, wherein the first poly(hydroxyalkanoate) comprises a copolymer and R1 is methyl.

[0081] Embodiment 5. The biodegradable aqueous mixture of embodiment 4, wherein the poly(hydroxyalkanoate) copolymer comprises from about 10 to about 90 mole percent of first repeat units and from about 90 to about 10 mole percent of second repeat units.

[0082] Embodiment 6. The biodegradable aqueous mixture of embodiment 3, wherein the first poly(hydroxyalkanoate) comprises a terpolymer, R1 is methyl, and R2 is propyl.

[0083] Embodiment 7. The biodegradable aqueous mixture of embodiment 6, wherein the poly(hydroxyalkanoate) copolymer comprises about 15 to about 75 mole percent of first repeat units, about 75 to about 15 mole percent of second repeat units, and about 1 to about 5 mole percent of third repeat units.

[0084] Embodiment 8. The biodegradable aqueous mixture of any one of the preceding embodiments, wherein the first poly(hydroxyalkanoate) has a weight average molecular weight of at least 50,000 Daltons as specified by ASTM D4001-20.

[0085] Embodiment 9. The biodegradable aqueous mixture of any one 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 by ASTM D4001-20.

[0086] Embodiment 10. The biodegradable aqueous mixture of any one of the preceding embodiments, wherein the solid further comprises a second poly(hydroxyalkanoate) that does not include 3-hydroxypropionate monomer repeat units.

[0087] Embodiment 11. The biodegradable aqueous mixture of any one of the preceding embodiments, wherein the solid further comprises at least one biodegradable polymer selected from the group consisting of polybutylene succinate, polybutylene succinate-co-butylene adipate, polybutylene adipate-co-butylene terephthalate, polycaprolactone, polylactic acid, poly(vinyl alcohol), polyglycolic acid, polyglycolic acid / polylactic acid copolymer, cellulose acetate, nanocellulose, isosorbide esters, and mixtures thereof.

[0088] Embodiment 12. The biodegradable aqueous mixture of any one 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 poly(ethylene oxide) and poly(propylene oxide), poly(glycol ethers), poly(vinyl alcohols), alkyl sulfates, alkyl phosphates, stearates, and mixtures thereof.

[0089] Embodiment 13. The biodegradable aqueous mixture of any one 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, the rheology modifier being selected from the group consisting of polysaccharides, acrylate-based emulsion copolymers, viscosity reducers, and thickeners.

[0090] Embodiment 14. The biodegradable aqueous mixture of any one 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.

[0091] Embodiment 15. The biodegradable aqueous mixture of any one 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 bacteriostat.

[0092] Embodiment 16. The biodegradable aqueous mixture of any one of the preceding embodiments, wherein the mixture further comprises from 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 biosuccinic acid-based coalescing solvents, 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate, dimethyl carbonate, methanol, ethanol, ketones, acetates, and / or mixtures thereof.

[0093] Embodiment 16. The biodegradable aqueous mixture of any one of the preceding embodiments, wherein the mixture further comprises about 0.05 to about 1 weight percent of at least one antifoaming agent, the antifoaming agent being selected from the group consisting of polyether siloxanes, polyamide particles, and mixtures thereof.

[0094] Embodiment 17. The biodegradable aqueous mixture of any one of the preceding embodiments, wherein the mixture further comprises from about 1 weight percent to about 35 weight percent of at least one bulking agent, the bulking agent being selected from the group consisting of clay, calcium carbonate, talc, kaolinite, montmorillonite, bentonite, silica, chitin, titanium dioxide, nanoclay, or mixtures thereof.

[0095] Embodiment 18. The biodegradable aqueous mixture of any one of the preceding embodiments, wherein the mixture comprises poly(hydroxyalkanoate) particles having a Dv(90) particle size of about 20 microns or less, more preferably about 10 microns or less, as determined using ISO 8130-13:201.

[0096] Embodiment 19. The biodegradable aqueous mixture of any one of the preceding embodiments, wherein the mixture, when applied as a substrate coating, has an oxygen transmission rate, as determined according to ASTM D3985, of less than 50 cc / m2 / 24h.

[0097] Embodiment 20. The mixture, when applied as a substrate coating, has an oxygen transmission rate, as determined in accordance with ASTM D3985, of 10 to 50 cc / m 2 10. The biodegradable aqueous mixture of any one of the preceding embodiments, wherein the biodegradable aqueous mixture is 0.1% or more per 24 hours.

[0098] Embodiment 21. The mixture, when applied as a substrate coating, has a water vapor transmission rate of 50 g / m according to ASTM F1249. 2 10. The biodegradable aqueous mixture of any one of the preceding embodiments, wherein the biodegradable aqueous mixture has a viscosity of less than 1000 saturations / 24 h.

[0099] Embodiment 22. The mixture, when applied as a substrate coating, has a water vapor transmission rate of 10 to 50 g / m according to ASTM F1249. 2 10. The biodegradable aqueous mixture of any one of the preceding embodiments, wherein the biodegradable aqueous mixture is 0.1% or more per 24 hours.

[0100] Embodiment 23. A coated substrate comprising:

[0101] a paperboard substrate having at least a first surface and a second surface; and

[0102] a coating layer on at least the first surface, wherein the coating is formed by applying the biodegradable aqueous mixture according to any one of the preceding embodiments. The coated substrate.

[0103] Embodiment 24. The coating has a coating weight of about 5 to about 20 g / m as specified by ASTM F2217. 2 24. The coated substrate of embodiment 23, wherein the coated substrate is applied at a coating weight of

[0104] The foregoing description of preferred embodiments of the present disclosure has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure to the precise form disclosed. Obvious modifications or variations are possible in light of the above teachings. The embodiments have been chosen and described in an effort to provide the best explanation of the principles of the disclosure and its practical application, thereby enabling others skilled in the art to utilize the disclosure in various embodiments, with various modifications appropriate to the particular uses contemplated.

Claims

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

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

3. The first poly(hydroxyalkanoate) is a copolymer or terpolymer having: a first repeat unit which is (3-hydroxypropionate); a second repeat unit according to formula I; 【Chemical 1】 and optionally a third repeat unit according to formula II; 【Chemistry 2】 Including, wherein R1 and R2 are each independently selected from the group consisting of straight or branched chain alkyl groups having 1 to 22 carbon atoms; The biodegradable aqueous mixture according to claim 1.

4. The first poly(hydroxyalkanoate) comprises a copolymer, and R １ The biodegradable aqueous mixture according to claim 3, wherein is methyl.

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

6. The first poly(hydroxyalkanoate) comprises a terpolymer, R １ is methyl, and R ２ The biodegradable aqueous mixture according to claim 3, wherein is propyl.

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

8. 10. 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 by ASTM D4001-20.

9. 2. 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 by ASTM D4001-20.

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

11. 10. The biodegradable aqueous mixture of claim 1, wherein the solid further comprises at least one biodegradable polymer selected from the group consisting of polybutylene succinate, polybutylene succinate-co-butylene adipate, polybutylene adipate-co-butylene terephthalate, polycaprolactone, polylactic acid, poly(vinyl alcohol), polyglycolic acid, polyglycolic acid / polylactic acid copolymer, cellulose acetate, nanocellulose, isosorbide esters, and mixtures thereof.

12. 10. The biodegradable aqueous mixture of claim 1, wherein the mixture further comprises 0.01 weight percent 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 poly(ethylene oxide) and poly(propylene oxide), poly(glycol ethers), poly(vinyl alcohols), alkyl sulfates, alkyl phosphates, stearates, and mixtures thereof.

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

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

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

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

17. 10. The biodegradable aqueous mixture of claim 1, wherein the mixture further comprises 1 weight percent to 35 weight percent of at least one bulking agent selected from the group consisting of clay, calcium carbonate, talc, kaolinite, montmorillonite, bentonite, silica, chitin, titanium dioxide, nanoclay, or mixtures thereof.

18. 10. The biodegradable aqueous mixture of claim 1, wherein the mixture comprises poly(hydroxyalkanoate) particles having a Dv(90) particle size of 20 microns or less as determined using ISO 8130-13:

201.

19. The mixture, when applied as a substrate coating, has an oxygen transmission rate of 50 cc / m as determined in accordance with ASTM D3985. ２ 2. The biodegradable aqueous mixture according to claim 1, wherein the retention time is less than 24 hours.

20. The mixture, when applied as a substrate coating, has an oxygen transmission rate, as determined in accordance with ASTM D3985, of 10 to 50 cc / m ２ 2. The biodegradable aqueous mixture according to claim 1, wherein the drying time is 24 hours.

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

22. The mixture, when applied as a substrate coating, has a water vapor transmission rate of 10 to 50 g / m according to ASTM F1249. ２ 2. The biodegradable aqueous mixture according to claim 1, wherein the viscosity is 100 s / 24hg / m2 / 24h.

23. A coated substrate comprising: a paperboard substrate having at least a first surface and a second surface; and and a coating layer on at least the first surface, the coating being formed by applying the biodegradable aqueous mixture according to claim 1. The coated substrate.

Images