Biodegradable coated paper articles, and methods thereof

Abstract

Biodegradable coated paper articles comprising a paper substrate and a layer provided on said paper substrate, wherein the layer is formed from a biodegradable coating composition comprising: a. a cellulose ester which is a cellulose acetate propionate (CAP) in an amount of 5.5 to 15 weight %, based on the total weight of (a), (b), and (c); b. a biodegradable polymer which is a polyester in amount of 45 to 75 weight %, based on the total weight of (a), (b), and (c); and c. an inorganic filler in an amount of 12 to 40 weight %, based on the total weight of (a), (b), and (c); wherein the polyester is selected from the group consisting of poly(butylene succinate) (PBS), poly(butylene succinate adipate) (PBSA), polycaprolactone (PCL), poly(butylene adipate terephthalate) (PBAT), polylactic acid (PLA), and combinations thereof.

Description

BIODEGRADABLE COATED PAPER ARTICLES, AND METHODS THEREOFTECHNICAL FIELD

[0001] Embodiments of the present disclosure generally relate to biodegradable coated paper articles, and methods of manufacturing biodegradable coated paper articles.BACKGROUND

[0002] Paper products in general (such as, paper cup, paper bowl, paper plate, paper box and paper lunch box, drink box, nonwoven cloth, and paper container, etc), is becoming more popular amongst consumers because it is regarded as more natural, more biodegradable, and more recyclable. Uncoated paper-based packaging is typically highly biodegradable in certain environments and is very easily recyclable in commercial paper recycling systems. However, a paper with no coating or adhesive at all cannot easily be formed into a paper product. Also, uncoated paper products have poor water / moisture barrier properties.

[0003] To improve the barrier properties, a polyethylene-based or other non- biodegradable polymeric is coated on the surface of the paper. However, if the coating is too thick, it may negatively affect the recyclability of the paper laminate in typical commercial paper recycling systems. Examples of such issues may include: i) coatings that clog the filters in repulping tanks and systems; ii) coatings that hold tightly onto the paper fibers and prevent a high % of the paper fibers being released into the water of the repulping system; iii) coatings that end up being incorporated into the recycled paper and negatively affect the appearance or performance properties of the resulting recycled paper. If the coating is made too thin, the overall structure might be considered recyclable in the paper recycling stream if it can be stripped off and sent to a landfill or burned to fuel the plant, leaving the paper fibers to be collected and recycled into paper. However, such a structure still has several disadvantages because if it is improperly disposed of in the environment, the paper would biodegrade, but not the polyethylene-based or other non-biodegradable coating. This can lead to persistent microplastics negatively impacting the environment or appearing as a non-nutritive food source for some animals.

[0004] To address the concerns with using polyethylene-based or other non- biodegradable polymeric materials, bio-based and biodegradable materials are under development. However, some new bio-based and biodegradable materials have poor processability (slow coating and conversion speed), poor paper adhesion for thin coating, and high water vapor transmission rate.

[0005] To address some of these concerns, manufacturers have resorted to modify existing coating / conversion machines and coat thicker coatings. However, these changes significantly increase the cost and also slow down the biodegradation rate of the coated paper articles.

[0006] Accordingly, there remains a need for a biodegradable coating composition that can be more efficiently coated to paper with good paper adhesion and thin coating so that the resulted paper articles will have low water vapor transmission rate and fast biodegradation rate.SUMMARY

[0007] Disclosed in embodiments herein are biodegradable coated paper articles. The articles comprise a paper substrate and a layer provided on said paper substrate, wherein the layer is formed from a biodegradable coating composition comprising (alternatively, consisting essentially of or consisting of): a. a cellulose ester which is a cellulose acetate propionate (CAP) in an amount of 5.5 to 15 weight %, based on the total weight of (a), (b), and (c); b. a biodegradable polymer which is a polyester in amount of 45 to 75 weight %, based on the total weight of (a), (b), and (c); and c. an inorganic filler in an amount of 12 to 40 weight %, based on the total weight of (a), (b), and (c); wherein the polyester is selected from the group consisting of poly(butylene succinate) (PBS), poly(butylene succinate adipate) (PBSA), polycaprolactone (PCL), poly(butylene adipate terephthalate) (PBAT), polylactic acid (PLA), and combinations thereof, wherein the CAP has an averagedegree of substitution for hydroxyl substituents (DSOH) that is from 0.3 to 1.2, an average degree of substitution for the acetyl substituents (DS Ac) that is from 0 to 0.5, an average degree of substitution for the propionyl substituents (DSPr) that is from 1.8 to 2.7, and a ball drop viscosity of from 0.05 to 30 seconds as measured according to ASTM D-1343, wherein the biodegradable coating composition has a glass transition temperature (Tg) of -40 to -10°C, a melting temperature (Tm) of 80 to 110°C, and a crystallization temperature (Tc) of 40 to 70°C, and wherein the biodegradable coating composition has a Young’s modulus of greater than 700 MPa, elongation at break of 10 to 300%, and water vapor transmission rate (WVTR) of less than 600 g mil / (m2day).

[0008] Also disclosed in embodiments herein are methods of manufacturing biodegradable coated paper articles. The methods comprise: providing a paper substrate; extrusion coating a layer onto the paper substrate to form a biodegradable coated paper article, wherein the layer is formed from a biodegradable coating composition comprising (alternatively, consisting essentially of or consisting of): a. a cellulose ester which is a cellulose acetate propionate (CAP) in an amount of 5.5 to 15 weight %, based on the total weight of (a), (b), and (c); b. a biodegradable polymer which is a polyester in amount of 45 to 75 weight %, based on the total weight of (a), (b), and (c); and c. an inorganic filler in an amount of 12 to 40 weight %, based on the total weight of (a), (b), and (c); wherein the polyester is selected from the group consisting of poly(butylene succinate) (PBS), poly(butylene succinate adipate) (PBSA), polycaprolactone (PCL), poly(butylene adipate terephthalate) (PBAT), polylactic acid (PLA), and combinations thereof, wherein the CAP has an average degree of substitution for hydroxyl substituents (DSOH) that is from 0.3 to 1.2, an average degree of substitution for the acetyl substituents (DSAc) that is from 0 to 0.5, an average degree of substitution for the propionyl substituents (DSPr) that is from 1.8 to 2.7, and a ball drop viscosity of from 0.05 to 30 seconds as measured according to ASTM D-1343, wherein the biodegradable coating composition has a glass transition temperature (Tg) of -40 to -10°C, a melting temperature (Tm) of 80 to 110°C, and a crystallization temperature (Tc) of 40 to 70°C, and wherein the biodegradable coating composition has aYoung’s modulus of greater than 700 MPa, elongation at break of 10 to 300%, and water vapor transmission rate (WVTR) of less than 600 g mil / (m2day).

[0009] In one or more embodiments herein, the polyester is selected from the group consisting of poly(butylene succinate) (PBS), poly(butylene succinate adipate) (PBSA), poly(butylene adipate terephthalate) (PBAT), or a mixture thereof.

[0010] In one or more embodiments herein, the inorganic filler is calcium carbonate.

[0011] In one or more embodiments herein, the inorganic filler is in an amount of 20 to 40 wt.% of the biodegradable coating composition.

[0012] In one or more embodiments herein, the CAP has an average degree of substitution for hydroxyl substituents that is from 0.5 to 1.0, an average degree of substitution for the acetyl substituents (DSAc) that is from 0 to 0.2, an average degree of substitution for the propionyl substituents (DSPr) that is from 2.0 to 2.5, and a ball drop viscosity of from 0.1 to 5 seconds as measured according to ASTM D-1343.

[0013] In one or more embodiments herein, the biodegradable coating composition has a crystallization temperature (Tc) of 40 to 60 °C.

[0014] In one or more embodiments herein, the biodegradable coating composition has a viscosity at 200 °C and 10 rad / s (V200) of 500 to 800 Pa s and a viscosity ratio (V65 / V200) of less than 28, where V65 is the viscosity measured at 65 °C and 10 rad / s.

[0015] In one or more embodiments herein, the paper substrate has a weight of 50 gsm to 350 gsm.DETAILED DESCRIPTION

[0016] Reference will now be made in detail to embodiments of biodegradable coated paper articles and methods of manufacturing thereof. The biodegradable coated paper articles may be used in the manufacture of food and beverage containers, such as, cups,plates, bowls, gable top cartons, folding cartons, paper pouches, and sandwich wraps. It is noted, however, that this is merely an illustrative implementation of the embodiments disclosed herein. The embodiments are applicable to other technologies that are susceptible to similar problems, paper bags, paper adhesive tape, paper labels, and ream wrap.

[0017] In embodiments herein, the biodegradable coated paper article, and its method of manufacture, comprise a paper substrate and a layer provided on said paper substrate, wherein the layer is formed from a biodegradable coating composition. The paper substrate has a weight basis of 50 gsm to 350 gsm. All individual values and subranges are included and disclosed herein. For example, in some embodiments, the paper substrate has a weight basis ranging from a lower limit of 50, 75, 100, 125, or 150 gsm to an upper limit of 350, 300, 250, 200, or 150 gsm. The paper substrates can be made from cellulosic or lignocellulosic materials. Examples of cellulosic raw materials include paper and paper products such as newsprint, poly-coated paper, and effluent from paper manufacture; examples of lignocellulosic raw materials include wood, wood fibers, and wood-related materials, as well as materials derived from kenaf, grasses, rice hulls, bagasse, cotton, jute, other stem plants (e.g., hemp, flax, bamboo; both bast and core fibers), leaf plants (e.g., sisal, abaca), and agricultural fibers (e.g., cereal straw, corn cobs, rice hulls, and coconut hair). Aside from virgin raw materials, post-consumer or post-industrial recycled materials, industrial (e.g., offal), and processing waste (e.g., effluent) can also be used as fiber sources.

[0018] The layer is formed from a biodegradable coating composition comprising (a) a cellulose ester, (b) a biodegradable polymer, and (c) an inorganic filler. In one or more embodiments herein, the biodegradable coating composition comprises 5.5 wt.% to 15 wt.%, based on the total weight of (a), (b), and (c), of the cellulose ester as described herein. All individual values and subranges are included and disclosed herein. For example, in some embodiments, the biodegradable coating composition comprises from a lower limit of 5.5, 5.8, 6.0, 6.2 or 6.5 wt.% to an upper limit of 15, 14, 13, or 12.5 wt.%, based on thetotal weight of (a), (b), and (c), of the cellulose ester. In other embodiments, the biodegradable coating composition comprises from 5.5 wt.% to 14 wt.%, 5.8 wt.% to 14 wt.%, or 6.0 wt.% to 12.5 wt.%, based on the total weight of (a), (b), and (c), of the cellulose ester. In one or more embodiments herein, the biodegradable coating composition comprises from 45 wt.% to 75 wt.%, based on the total weight of (a), (b), and (c), of a biodegradable polymer as described herein. All individual values and subranges are included and disclosed herein. For example, in some embodiments, the biodegradable coating composition comprises from a lower limit of 45, 47.5, 50, 52.5 or 55 wt.% to an upper limit of 75, 72.5, 70, 67.5 or 65 wt.%, based on the total weight of (a), (b), and (c), of the biodegradable polymer. In other embodiments, the biodegradable coating composition comprises from 45 wt.% to72.5 wt.%, 47. 5 wt.% to 72.5 wt.%, or 50 wt.% to 72.5 wt.%, based on the total weight of (a), (b), and (c), of the biodegradable polymer. In one or more embodiments herein, the biodegradable coating composition comprises from 12 to 40 weight %, based on the total weight of (a), (b), and (c), of an inorganic filler as described herein. All individual values and subranges are included and disclosed herein. For example, in some embodiments, the biodegradable coating composition comprises from a lower limit of 12, 15, 17.5 or 20 wt.% to an upper limit of 40, 37.5, or 35 wt.%, based on the total weight of (a), (b), and (c), of the inorganic filler. In other embodiments, the biodegradable coating composition comprises from 15 wt.% to 40 wt.%, 17.5 wt.% to 40 wt.%, or 20 wt.% to 40 wt.%, based on the total weight of (a), (b), and (c), of the inorganic filler.Cellulose Ester

[0019] The cellulose ester is a cellulose acetate propionate (CAP). The CAP has an average degree of substitution for the hydroxyl substituents (DSOH) that is from 0.3 to 1.2, an average degree of substitution for the acetyl substituents (DSAC) that is from 0 to 0.5, and an average degree of substitution for the propionyl substituents (DSPr) from 1.8 to 2.7. All individual values and subranges are included and disclosed herein. For example, in some embodiments, the CAP has an average degree of substitution for the hydroxylsubstituents (DSOH) that is from 0.3 to 1.1, 0.4 to 1.1, or 0.5 to 1.0, an average degree of substitution for the acetyl substituents (DSAC) that is from 0 to 0.4, 0 to 0.3, 0 to 0.25, or 0 to 0.2, and an average degree of substitution for the propionyl substituents (DSPr) from 1.9 to 2.6 or 2.0 to 2.5. In other embodiments, the CAP has an average degree of substitution for hydroxyl substituents that is from 0.5 to 1.0, an average degree of substitution for the acetyl substituents (DSAc) that is from 0 to 0.2, an average degree of substitution for the propionyl substituents (DSPr) that is from 2.0 to 2.5.

[0020] For cellulose esters, the substitution level is usually express in terms of degree of substitution (DS), which is the average number of non-OH substituents per anhydroglucose unit (AGU). Generally, conventional cellulose contains three hydroxyl groups in each AGU unit that can be substituted. As used herein, the term “degree of substitution” or “DS” refers to the average number of substituents per anhydroglucose ring of the cellulose polymer, wherein the maximum degree of substitution is 3.0. Because DS is a statistical mean value, a value of 1 does not assure that every AGU has a single substituent. In some cases, there can be unsubstituted anhydroglucose units, some with two and some with three substituents, and typically the value will be a non-integer. Total DS is defined as the average number of all of substituents per anhydroglucose unit. The degree of substitution per AGU can also refer to a particular substituent, such as, for example, hydroxyl (DSOH) or acetyl (DSAC).

[0021] In embodiments herein, the CAP has a ball drop viscosity of 0.05 to 30 seconds as measured according to ASTM DI 343. All individual values and subranges are included and disclosed herein. For example, in some embodiments, the CAP may have a ball drop viscosity of 0.05 to 10, 0.05 to 5, 0.05 to 2, or 0.1 to 2 seconds as measured according to ASTM DI 343. In other embodiments, the CAP may have a ball drop viscosity of 0.1 to 5 seconds as measured according to ASTM DI 343.

[0022] In one or more embodiments herein, the CAP has an average degree of substitution for the hydroxyl substituents (DSOH) that is from 0.3 to 1.2, an average degree of substitution for the acetyl substituents (DSAC) that is from 0 to 0.5, and an averagedegree of substitution for the propionyl substituents (DSPr) from 1.8 to 2.7, and have a ball drop viscosity of 0.05 to 30 seconds as measured according to ASTM D1343. All individual values and subranges are included and disclosed herein. For example, in some embodiments, the CAP has an average degree of substitution for the hydroxyl substituents (DSOH) that is from 0.3 to 1.1, 0.4 to 1.1, or 0.5 to 1.0, an average degree of substitution for the acetyl substituents (DSAC) that is from 0 to 0.4, 0 to 0.3, 0 to 0.25, or 0 to 0.2, and an average degree of substitution for the propionyl substituents (DSPr) from 1.9 to 2.6 or 2.0 to 2.5, and a ball drop viscosity of 0.05 to 10, 0.05 to 5, 0.05 to 2, or 0.1 to 2 seconds as measured according to ASTM D1343. In other embodiments, the CAP has an average degree of substitution for hydroxyl substituents that is from 0.5 to 1.0, an average degree of substitution for the acetyl substituents (DSAc) that is from 0 to 0.2, an average degree of substitution for the propionyl substituents (DSPr) that is from 2.0 to 2.5, and a ball drop viscosity of 0.1 to 5 seconds as measured according to ASTM DI 343.Biodegradable Polymer

[0023] In embodiments herein, the biodegradable polymer is a polyester. The polyester is selected from the group consisting of poly(butylene succinate) (PBS), poly(butylene succinate adipate) (PBSA), polycaprolactone (PCL), poly(butylene adipate terephthalate) (PBAT), polylactic acid (PLA), derivatives thereof, and combinations thereof. In some embodiments, the polyester is selected from the group consisting of poly(butylene succinate) (PBS), poly(butylene succinate adipate) (PBSA), poly(butylene adipate terephthalate) (PBAT), derivatives thereof, and combinations thereof. In other embodiments, the polyester is selected from the group consisting of poly(butylene succinate) (PBS), poly(butylene succinate adipate) (PBSA), derivatives thereof, and combinations thereof. In further embodiments, the polyester is selected from the group consisting of poly(butylene succinate) (PBS), poly(butylene succinate adipate) (PBSA), polycaprolactone (PCL), poly(butylene adipate terephthalate) (PBAT), polylactic acid (PLA), and combinations thereof. In even further embodiments, the polyester is selectedfrom the group consisting of poly(butylene succinate) (PBS), poly(butylene succinate adipate) (PBSA), poly(butylene adipate terephthalate) (PBAT), and combinations thereof.Inorganic Filler

[0024] Examples of suitable inorganic fillers may include calcium carbonate, titanium dioxide, aluminum oxide, silicon dioxide, aluminosilicates, diatomaceous earth, magnesium oxide, talc, mica, zinc oxide, clay, barium sulfate, and mixtures thereof. In some embodiments herein, the inorganic filler is calcium carbonate, titanium dioxide, mica, or mixtures thereof. In other embodiments, the inorganic filler is calcium carbonate.

[0025] In embodiments herein, the biodegradable coating composition has a glass transition temperature (Tg) of -40 to -10°C, a melting temperature (Tm) of 80 to 110°C, and a crystallization temperature (Tc) of 40 to 70°C. All individual values and subranges are included and disclosed herein. For example, in some embodiments, the biodegradable coating composition has a glass transition temperature (Tg) of -40 to -10°C, -35 to -15°C, -30 to -15°C, or -30 to -20°C; a melting temperature (Tm) of 80 to 110°C, 85 to 110°C, 90 to 105°C, or 92.5 to 102.5°C; and a crystallization temperature (Tc) of 40 to 70°C, 40 to 65°C, 40 to 60°C, or 42.5 to 58°C.

[0026] In embodiments herein, the biodegradable coating composition has a Young’s modulus of greater than 700 MPa, elongation at break of 10 to 300%, and water vapor transmission rate (WVTR) of less than 600 g-mil / (m2-day). All individual values and subranges are included and disclosed herein. For example, in some embodiments, the biodegradable coating composition has a Young’s modulus of greater than 700 MPa, greater than 800 MPa, greater than 900 MPa, or greater than 1 ,000 MPa; an elongation at break of 10 to 300%, 10 to 275%, or 10 to 250%,; and water vapor transmission rate (WVTR) of less than 600 g-mil / (m2-day), from 400 to 600 g- mil / (m2- day), or from 400 to 585 g-mil / (m2-day).

[0027] In one or more embodiments herein, the biodegradable coating composition may have a viscosity at 200 °C and 10 rad / s (V200) of 500 to 800 Pa-s and a viscosity ratio (V65 / V200) of less than 28, where V65 is the viscosity measured at 65 °C and 10 rad / s. All individual values and subranges are included and disclosed herein. For example, in some embodiments, the biodegradable coating composition may have a viscosity at 200 °C and 10 rad / s (V200) of 500 to 800 Pa- s or 500 to 750 Pa- s and a viscosity ratio (V65 / V200) of less than 28 or from 10 to 28, where V65 is the viscosity measured at 65 °C and 10 rad / s. Without being bound by theory, it is believed that the viscosity and the viscosity ratio (V65 / V200) parameters are indicative of extrusion coating speeds and paper adhesion, such that a certain range of viscosity (i.e., the claimed range) at 200 °C can indicate higher coating speeds and a certain range (i.e., the claimed range) of viscosity ratio, V65 / V200, can indicate better paper adhesion without any chill roll sticky issue.

[0028] Also disclosed in embodiments described herein are methods of manufacturing biodegradable coated paper articles. The method comprises providing a paper substrate; extrusion coating a layer onto the paper substrate to form a biodegradable coated paper article, wherein the layer is formed from the biodegradable coating compositions as previously described herein. In some embodiments, the layer is a monolayer formed on the paper substrate. In other embodiments, the layer is a multilayer (i.e., two or more layers) formed on the paper substrate. In further embodiments, the layer is a multilayer formed on the paper substrate, wherein at least one of the multilayers is formed from the biodegradable coating compositions as previously described herein.TEST METHODSViscosity

[0029] Viscosity is measured using a TA Instruments ARES-G2. Prior to measuring viscosity, the samples are dried in a vacuum oven for two days at 60 °C. The temperature sweeps are determined by measuring the viscosity from 230°C to 50°C at 10 rad / sec. Theramp rate is 5 °C / min and sampling interval is 10 seconds using a strain rate of 10%. The results are reported in Pa s.Differential Scanning Calorimetry (DSC)

[0030] The thermal transitions of the artificial turf infill coating compositions are measured by differential scanning calorimetry (DSC) using a DSC instrument (Q 2000, TA Instruments, New Castle, DE, USA). To analyze, 4 to 8 mg of each sample is sealed in an aluminum DSC pan and evaluated using a “heat-cool-heat” method. For the 1stheat, the samples are evaluated from -80 °C to 250 °C at a scan rate of 20°C per min. Next, the sample is cooled from 250 °C to -80 °C at a scan rate of 20 °C per min and the midpoint transition value is marked as “Tc.” Finally, the samples are reheated a second time from - 80 °C to 250 °C at a scan rate of 20 °C per min and the midpoint transition values are marked as Tg and Tm. Tg is the glass transition temperature, Tm is the melting point, and Tc is the crystallization temperature. The values are reported in degrees Celsius (°C).Tensile Properties

[0031] The tensile properties are tested using ASTM D638-V method. Samples are pressure molded to 500 pm films at 200 °C. Young’s Modulus is reported in MPa and Elongation at Break is reported in %.Water Vapor Transition Rate (WVTR)

[0032] The WVTR is measured according to ASTM F1249 method. Samples are pressure molded to 250 pm films at 200 °C. WVTR is reported in g mil / (m2day).Nuclear Magnetic Resonance (NMR)

[0033] 20 mg of sample is dissolved in 1 mF deuterated dimethylsulfoxide at 80 °C.85 pF trifluoroacetic acid-d / tetramethylsilane (TFA-d / TMS) solution is added to the vial and swirled slowly. The solution is then pipetted into 5 mm NMR tube. Proton NMR datais obtained on a Bruker Avance III 600 MHz spectrometer. Each spectrum is processed using ACD-Spectrus Processor software.Ball Drop Viscosity

[0034] Ball drop viscosity is measured according to ASTM D1343. The results are reported in seconds.EXAMPLES

[0035] The following specific examples are given to illustrate the process and performance properties associated with biodegradable coated paper articles and its components. The inventive and comparative examples are provided below with the details of the formulations and results are provided in the Tables below.Table 1 - Raw MaterialsTable 2 - CAP Resin Properties

[0036] Biodegradable coating compositions are formulated according to the following procedure: an 18 mm Leistritz twin screw extruder with single-hole die is used to compound the formulations and produce pellets. All resins are dried at 60-80 °C for at least 4 hours. All formulations are compounded at 180 to 230 °C without vacuum. The formulation details are shown in Table 3 below.Table 3 - Biodegradable Coating Compositions

[0037] The examples are analyzed for various properties and characteristics, and the results are shown in Tables 4-7.Table 4 - DSC ValuesTable 5 - ViscosityTable 6 - Tensile PropertiesTable 7 - Water Vapor Transmission Rate (WVTR)

[0038] Additional formulation examples are produced according to the same procedure used for examples 1-19 above. The details of the formulation as well as the DSC analysis is shown below in Table 8.Table 8 - Biodegradable Coating Compositions & DSC

[0039] The dimensions and values disclosed herein are not to be understood as being strictly limited to the exact numerical values recited. Instead, unless otherwise specified, each such dimension is intended to mean both the recited value and a functionally equivalent range surrounding that value. For example, a dimension disclosed as “40 mm” is intended to mean “about 40 mm.”

[0040] Every document cited herein, if any, including any cross- referenced or related patent or application and any patent application or patent to which this application claims priority or benefit thereof, is hereby incorporated herein by reference in its entirety unless expressly excluded or otherwise limited. The citation of any document is not an admission that it is prior art with respect to any invention disclosed or claimed herein or that it alone, or in any combination with any other reference or references, teaches, suggests or discloses any such invention. Further, to the extent that any meaning or definition of a term in this document conflicts with any meaning or definition of the same term in a document incorporated by reference, the meaning or definition assigned to that term in this document shall govern.

[0041] While particular embodiments of the present invention have been illustrated and described, it would be obvious to those skilled in the art that various other changes and modifications can be made without departing from the spirit and scope of the invention. It is therefore intended to cover in the appended claims all such changes and modifications that are within the scope of this invention.

Claims

What is claimed is:

1. A biodegradable coated paper article, the article comprising a paper substrate and a layer provided on said paper substrate, wherein the layer is formed from a biodegradable coating composition comprising: a. a cellulose ester which is a cellulose acetate propionate (CAP) in an amount of 5.5 to 15 weight %, based on the total weight of (a), (b), and (c); b. a biodegradable polymer which is a polyester in amount of 45 to 75 weight %, based on the total weight of (a), (b), and (c); and c. an inorganic filler in an amount of 12 to 40 weight %, based on the total weight of (a), (b), and (c); wherein the polyester is selected from the group consisting of poly(butylene succinate) (PBS), poly(butylene succinate adipate) (PBSA), polycaprolactone (PCL), poly(butylene adipate terephthalate) (PBAT), polylactic acid (PLA), derivatives thereof, and combinations thereof, wherein the CAP has an average degree of substitution for hydroxyl substituents (DSOH) that is from 0.3 to 1.2, an average degree of substitution for the acetyl substituents (DS Ac) that is from 0 to 0.5, an average degree of substitution for the propionyl substituents (DSPr) that is from 1.8 to 2.7, and a ball drop viscosity of from 0.05 to 30 seconds as measured according to ASTM D-1343, wherein the biodegradable coating composition has a glass transition temperature (Tg) of -40 to -10°C, a melting temperature (Tm) of 80 to 110°C, and a crystallization temperature (Tc) of 40 to 70°C, and wherein the biodegradable coating composition has a Young’s modulus of greater than 700 MPa, elongation at break of 10 to 300%, and water vapor transmission rate (WVTR) of less than 600 g-mil / (m2-day).

2. The biodegradable coated paper article of claim 1 , wherein the polyester is selected from the group consisting of poly(butylene succinate) (PBS), poly(butylene succinate adipate) (PBSA), poly(butylene adipate terephthalate) (PBAT), derivatives thereof, and combinations thereof.

3. The biodegradable coated paper article of claims 1 or 2, wherein the inorganic filler is calcium carbonate.

4. The biodegradable coated paper article of claims 1-3, wherein the inorganic filler is in an amount of 20 to 40 wt.% of the biodegradable coating composition.

5. The biodegradable coated paper article of claims 1-4, wherein the CAP has an average degree of substitution for hydroxyl substituents that is from 0.5 to 1.0, an average degree of substitution for the acetyl substituents (DSAc) that is from 0 to 0.2, an average degree of substitution for the propionyl substituents (DSPr) that is from 2.0 to 2.5, and a ball drop viscosity of from 0.1 to 5 seconds as measured according to ASTM D-1343.

6. The biodegradable coated paper article of claims 1-5, wherein the biodegradable coating composition has a crystallization temperature (Tc) of 40 to 60 °C.

7. The biodegradable coated paper article of claims 1-6, wherein the biodegradable coating composition has a viscosity at 200 °C and 10 rad / s (V200) of 500 to 800 Pa-s and a viscosity ratio (V65 / V200) of less than 28, where V65 is the viscosity measured at 65 °C and 10 rad / s.

8. The biodegradable coated paper article of claims 1-7, wherein the paper substrate has a weight of 50 gsm to 350 gsm.

9. A method of manufacturing a biodegradable coated paper article, the method comprising: providing a paper substrate; extrusion coating a layer onto the paper substrate to form a biodegradable coated paper article, wherein the layer is formed from a biodegradable coating composition comprising:a. a cellulose ester which is a cellulose acetate propionate (CAP) in an amount of 5.5 to 15 weight %, based on the total weight of (a), (b), and (c); b. a biodegradable polymer which is a polyester in amount of 45 to 75 weight %, based on the total weight of (a), (b), and (c); and c. an inorganic filler in an amount of 12 to 40 weight %, based on the total weight of (a), (b), and (c); wherein the polyester is selected from the group consisting of poly(butylene succinate) (PBS), poly(butylene succinate adipate) (PBSA), polycaprolactone (PCL), poly(butylene adipate terephthalate) (PBAT), polylactic acid (PLA), derivatives thereof, and combinations thereof, wherein the CAP has an average degree of substitution for hydroxyl substituents (DSOH) that is from 0.3 to 1.2, an average degree of substitution for the acetyl substituents (DS Ac) that is from 0 to 0.5, an average degree of substitution for the propionyl substituents (DSPr) that is from 1.8 to 2.7, and a ball drop viscosity of from 0.05 to 30 seconds as measured according to ASTM D-1343, wherein the biodegradable coating composition has a glass transition temperature (Tg) of -40 to -10°C, a melting temperature (Tm) of 80 to 110°C, and a crystallization temperature (Tc) of 40 to 70°C, and wherein the biodegradable coating composition has a Young’s modulus of greater than 700 MPa, elongation at break of 10 to 300%, and water vapor transmission rate (WVTR) of less than 600 g-mil / (m2-day).

10. The method of claim 9, wherein the polyester is selected from the group consisting of poly(butylene succinate) (PBS), poly(butylene succinate adipate) (PBSA), poly(butylene adipate terephthalate) (PBAT), derivatives thereof, and combinations thereof.

11. The method of claims 9 or 10, wherein the inorganic filler is calcium carbonate.

12. The method of claims 9-11, wherein the inorganic filler is in an amount of 20 to 40 wt.% of the biodegradable coating composition.

13. The method of claims 9-12, wherein the CAP has an average degree of substitution for hydroxyl substituents that is from 0.5 to 1.0, an average degree of substitution for the acetyl substituents (DSAc) that is from 0 to 0.2, an average degree of substitution for the propionyl substituents (DSPr) that is from 2.0 to 2.5, and a ball drop viscosity of from 0.1 to 5 seconds as measured according to ASTM D-1343.

14. The method of claims 9-13, wherein the biodegradable coating composition has a crystallization temperature (Tc) of 40 to 60 °C.

15. The method of claims 9-14, wherein the biodegradable coating composition has a viscosity at 200 °C and 10 rad / s (V200) of 500 to 800 Pa- s and a viscosity ratio (V65 / V200) of less than 28, where V65 is the viscosity measured at 65 °C and 10 rad / s.

16. The method of claims 9-15, wherein the paper substrate has a weight of 50 gsm to 350 gsm.

Images