EP4483012A2

EP4483012A2 - Method and apparatus for molding of cnf-cmc onto molded pulp

Info

Publication number: EP4483012A2
Application number: EP23760540.7A
Authority: EP
Inventors: Jeffrey Youngblood; Endrina FORTI; Jiangxuan ZHANG
Original assignee: Purdue Research Foundation
Current assignee: Purdue Research Foundation
Priority date: 2022-02-22
Filing date: 2023-02-15
Publication date: 2025-01-01
Also published as: CA3243511A1; AU2023224020A1; EP4483012A4; MX2024009683A; WO2023163888A3; US20250145322A1; WO2023163888A2

Abstract

A method of overmolding an object of interest with a protective coating is disclosed, which includes receiving a mold having a top half and a bottom half dimensioned for an object of interest, placing the object of interest into the bottom half of the mold, spreading a layer or laying a sheet of a mixture cellulose nanofibril (CNF) and carboxymethyl cellulose (CMC) on to the object of interest, placing the top half of the mold onto the CNF/CMC layer, applying a predetermined pressure between the top and bottom halves of the mold, applying a predetermined amount of heat to the mold, to thereby molding the CNF/CMC mixture onto the object of interest, and removing the object of interest with the layer of CNF/CMC formed thereon from the mold after a predetermined amount of time.

Description

METHOD AND APPARATUS FOR MOLDING OF CNF-CMC ONTO MOLDED PULP

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This patent application is related to an international co-owned patent application PCT/US21/20178, published as WO 2021/178262, as well this patent application claims priority to a provisional patent application S/N 63/312,659 filed February 22, 2022, contents of each of which are incorporated by reference in their entirety into the present disclosure.

STATEMENT REGARDING GOVERNMENT FUNDING

[0002] None.

TECHNICAL FIELD

[0003] The present disclosure generally relates to a novel processing method of molding cellulose nanofibril (CNF) and carboxymethyl cellulose (CMC) onto a molded pulp and specifically to a process of co-molding or overmolding CNF/CMC onto a molded pulp.

BACKGROUND

[0004] This section introduces aspects that may help facilitate a better understanding of the disclosure. Accordingly, these statements are to be read in this light and are not to be understood as admissions about what is or is not prior art.

[0005] CNM such as CNF were first isolated through homogenization of bleached cellulose pulp in the early 1980s. The extracted CNMs possess high aspect ratios (L/D = 5 to 500), high crystalline contents (27% to >80%, depending on the source and extraction process), and native surface hydroxyl groups that can form hydrogen bonds with surrounding fibers. Due to their morphological properties, inherent sustainability, uniformity, and their abundance in nature, CNMs have become an attractive material to reduce the dependence on oil-derived synthetic polymers.

[0006] Different methods have been introduced to prepare CNF or a combination of CNF/CMC on various object. Extrusion is one such method discussed in the co-owned international patent application PCT/US21/20178, published as WO 2021/178262. However, extrusion and related processes still require formation of the extruded material onto an object of interest which requires complicated post-processes such as vacuum- forming. Without such complicated postprocessing processes, it is possible that portions of the object are ill-prepared with gaps in coverage and adhesion.

[0007] Therefore, there is an unmet need for a novel approach to apply CNF or CNF/CMC as a layer onto an object of interest that provides good and uniform adhesion over the entirety of the object’s surface.

SUMMARY

[0008] A method of overmolding an object of interest with a protective coating is disclosed. The method includes receiving a mold having a top half and a bottom half dimensioned for an object of interest, placing the object of interest into the bottom half of the mold, spreading a layer or laying a sheet of a mixture cellulose nanofibril (CNF) and carboxymethyl cellulose (CMC) on to the object of interest, placing the top half of the mold onto the CNF/CMC layer, applying a predetermined pressure between the top and bottom halves of the mold, applying a predetermined amount of heat to the mold, to thereby molding the CNF/CMC mixture onto the object of interest, and removing the object of interest with the layer of CNF/CMC formed thereon from the mold a predetermined amount of time.

[0009] In the above method, the object of interest is a molded pulp.

[0010] In the above method, the molded pulp is a food carton.

[0011] In the above method, the molded pulp is a pharmaceutical carton.

[0012] In the above method, the mixture of CNF/CMC has a CMC to CNF weight ratio range of between about 0.03:1 to about 0.3:1.

[0013] In the above method, the weight ratio range is between about 0.03:1 to about 0.2:1. [0014] In the above method, the weight ratio range is between about 0.03:1 to about 0.1:1. [0015] In the above method, the weight ratio range is between about 0.05:1 to about 0.2:1.

[0016] In the above method, the weight ratio range is between about 0.05:1 to about 0.15:1.

[0017] In the above method, the weight ratio range is between about 0.1:1 to about 0.2:1.

[0018] In the above method, the weight ratio range is between about 0.1:1 to about 0.15:1.

[0019] In the above method, the CNF/CMC coated object of interest can withstand about 3X higher stress as compared to an uncoated object of interest prior to onset of plastic deformation. [0020] In the above method, the CNF/CMC coated object of interest can withstand about 1.6X higher load as compared to an uncoated object of interest prior to being crushed.

[0021] In the above method, the CNF/CMC coated object of interest has a kit grease resistance value of 6 to 8 as compared to an uncoated object of interest with a kit value of 1.

[0022] In the above method, the CNF/CMC coated object of interest has 20% or more higher resistance to moisture as compared to an uncoated object of interest as measured by WVTR. [0023] In the above method, the top half of the mold includes a plurality of through -holes.

[0024] In the above method, the the bottom half of the mold includes a plurality of through- holes.

[0025] In the above method, the predetermined pressure is about 1.5 KPa.

[0026] In the above method, the predetermined amount of heat causes the mold to reach between about 70 °C and about 110 °C.

[0027] In the above method, prior to spreading the layer of mixture of CNF/CMC, further comprising applying a layer of a primer or bonding agent to the object of interest.

[0028] In the above method, the primer or bonding agent comprises chitosan, cationic starch, and starch.

[0029] The above method, further includes placing an item of interest in the object of interest with the layer of CNF/CMC formed thereon, and lidding the item of interest with a pliable wrap. [0030] In the above method, the pliable wrap is selected from the group consisting of polyethylene terephthalate (PET), polypropylene, polylactic acid (PLA), and a combination thereof.

[0031] In the above method, the pliable wrap is made from low-density polyethylene (LDPE).

[0032] In the above method, LDPE includes linear low-density polyethylene as an additive.

[0033] In the above method, the pliable wrap is made from a bio-degradable material.

[0034] In the above method, the mixture of CNF/CMC further includes additives selected from the group consisting of polyvinylalcohol, starch, polyacrylamides, polyaziridine, polyamidoamine-epichlorohydrins, polycarbodiimides, ammonium zirconium carbonate, alkyl ketene dimers, silanes, anhydrides, and a combination thereof.

[0035] Another method of co-molding an object of interest with a protective coating is disclosed. The method includes receiving a mold having a top half and a bottom half dimensioned for an object of interest, placing a moldable material constituting raw material for the object of interest into the bottom half of the mold, spreading a layer or laying a sheet of a mixture of cellulose nanofibril (CNF) and carboxymethyl cellulose (CMC) on to the moldable material, placing the top half of the mold onto the CNF/CMC layer, applying a predetermined pressure between the top and bottom halves of the mold, applying a predetermined amount of heat to the mold, to thereby simultaneously molding both the object of interest and the CNF/CMC layer thereon, and removing the molded object of interest with the CNF/CMC layer formed thereon from the mold after a predetermined amount of time.

[0036] In the above method, the moldable material for the object of interest is a slurry of a fibrous pulp.

[0037] In the above method, the mixture of CNF/CMC further includes additives selected from the group consisting of polyvinylalcohol, starch, polyacrylamides, polyaziridine, polyamidoamine-epichlorohydrins, polycarbodiimides, ammonium zirconium carbonate, alkyl ketene dimers, silanes, anhydrides, and a combination thereof.

[0038] In the above method, the object of interest is a molded pulp.

[0039] In the above method, the molded pulp is a food carton.

[0040] In the above method, the molded pulp is a pharmaceutical carton.

[0041] In the above method, the mixture of CNF/CMC has a CMC to CNF weight ratio range of between about 0.03:1 to about 0.3:1.

[0042] In the above method, the weight ratio range is between about 0.03:1 to about 0.2:1.

[0043] In the above method, the weight ratio range is between about 0.03:1 to about 0.1:1.

[0044] In the above method, the weight ratio range is between about 0.05:1 to about 0.2:1.

[0045] In the above method, the weight ratio range is between about 0.05:1 to about 0.15:1.

[0046] In the above method, the weight ratio range is between about 0.1:1 to about 0.2:1.

[0047] In the above method, the weight ratio range is between about 0.1:1 to about 0.15:1.

[0048] In the above method, the CNF/CMC coated object of interest can withstand about 3X higher stress as compared to an uncoated object of interest prior to onset of plastic deformation. [0049] In the above method, the CNF/CMC coated object of interest can withstand about 1.6X higher load as compared to an uncoated object of interest prior to being crushed.

[0050] In the above method, the CNF/CMC coated object of interest has a kit grease resistance value of 6 to 8 as compared to an uncoated object of interest with a kit value of 1.

[0051] In the above method, the CNF/CMC coated object of interest has 20% or more higher resistance to moisture as compared to an uncoated object of interest as measured by WVTR. [0052] In the above method, the top half of the mold includes a plurality of through -holes.

[0053] In the above method, the predetermined pressure is between about 10 KPa to about 10 MPa.

[0054] In the above method, the predetermined amount of heat causes the mold to reach between 50 °C and 400 °C.

[0055] In the above method, prior to spreading the layer of mixture of CNF/CMC, further comprising applying a layer of a primer or bonding agent to the object of interest.

[0056] In the above method, the primer or bonding agent comprises chitosan, cationic starch, and starch.

[0057] The above method, further includes placing an item of interest in the object of interest with the layer of CNF/CMC formed thereon, and lidding the item of interest with a pliable wrap. In the above method, wherein the pliable wrap is selected from the group consisting of polyethylene terephthalate (PET), polypropylene, polylactic acid (PLA), and a combination thereof. In the above method, wherein the pliable wrap is made from low-density polyethylene (LDPE).In the above method, wherein LDPE includes linear low-density polyethylene as an additive.

[0058] In the above method, the pliable wrap is made from a bio-degradable material.

BRIEF DESCRIPTION OF DRAWINGS

[0059] FIG. 1 is a cross-sectional view of one embodiment of a mold apparatus used in the present disclosure.

[0060] FIG. 2 provides photographs of a flow of steps disclosed in the present disclosure.

[0061] FIG. 3 is a photograph of an example of mold halves of an example of FIG. 1 with holes provided in both halves for improved breathability of the molding process. [0062] FIG. 4 is a bar graph of Water Vapor Transport Rate (WVTR) in g/cm²-d vs. time in days showing results from coated molded pulp (MP) in dry form vs. coated MP in wet form vs. uncoated MP in dry form vs. uncoated MP in wet form.

[0063] FIG. 5 is a graph of stress (MPa) vs strain (%) curves for coated and uncoated MP samples in uniaxial tensile testing.

[0064] FIG. 6A is a graph of load in N vs. strain in % for five pulp samples in an uncoated state showing stress capabilities of the pulp without coating.

[0065] FIG. 6B is a graph of load in N vs. strain in % for five pulp samples in a coated state showing stress capabilities of the molded pulp with coating.

DETAILED DESCRIPTION

[0066] For the purposes of promoting an understanding of the principles of the present disclosure, reference will now be made to the embodiments illustrated in the drawings, and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of this disclosure is thereby intended.

[0067] In the present disclosure, the term “about” can allow for a degree of variability in a value or range, for example, within 10%, within 5%, or within 1% of a stated value or of a stated limit of a range.

[0068] In the present disclosure, the term “substantially” can allow for a degree of variability in a value or range, for example, within 90%, within 95%, or within 99% of a stated value or of a stated limit of a range.

[0069] A novel approach is presented herein for application of cellulose nanofibril (CNF) and carboxymethyl cellulose (CMC) (i.e., CNF or CNF/CMC) as a protective layer onto an object of interest that provides good and uniform adhesion over the entirety of the object’s surface. This protective layer is applied via an overmolding process, amongst other approaches. The protective layer provides numerous benefits to the object of interest, including i) protection against oxygen and oxygen radical transference from outside to interior compartments (thereby allowing the protected object to be used for preserving foods or pharmaceuticals in the associated protected package); ii) providing a moisture barrier from outside to inside or from inside to outside; iii) providing a grease barrier from outside to inside or from inside to outside; and iv) further stiffening the object.

[0070] The composition of CNF/CMC is of particular importance. According to one embodiment a CMC to CNF weight ratio range of 0.03:1 to 0.3:1 is utilized. In one aspect, the range is 0.03:1 to 0.2:1, 0.03:1 to 0.1:1, 0.05:1 to 0.2:1, 0.05:1 to 0.15:1, 0.1:1 to 0.2:1, or 0.1:1 to 0.15 : 1. In one aspect, a preferred ratio is about 0.1:1.

[0071] According to one embodiment, the present disclosure provides a molding apparatus and method to prepare an over-molded material comprising CNF and CMC, wherein the method comprises: providing a homogenous mixture comprising CNF and CMC, wherein the homogenous mixture has a solid content of 10-30 wt. %, and the homogenous mixture has a CMC/CNF weight ratio range of 0.03:1 to 0.3:1. In one aspect, the range is 0.03:1 to 0.2:1, 0.03:1 to 0.1:1, 0.05:1 to 0.2:1, 0.05:1 to 0.15:1, 0.1:1 to 0.2:1, or 0.1:1 to 0.15:1. In one aspect, a preferred ratio is about 0.1:1. The method also includes generating a mold for the object; loading the object onto the generated mold, loading the homogenous mixture comprising CNF and CMC onto the object which is loaded onto the mold; and molding the homogenous mixture comprising CNF and CMC to provide a material with the desired shape of the object.

[0072] Specifically, the present methodology deals with overmolding moldable CNF/CMC onto molded pulp to generate a package suitable for food that is fully compostable and degradable made of sustainable cellulose which benefits from the above-enumerated advances.

[0073] Cellulose is abundant in nature and can be extracted from many sources. Additionally, cellulose also has an inherent requisite thermal barrier and mechanical properties necessary for packaging in many industries. Advantageously, nanocellulose has been already extracted at industrial scale.

[0074] While CNF by itself is somewhat similar to a flaky material thus difficult to work with, a combination of CNF and CMC at an appropriate weight proportions is similar to putty in texture and constitution and is thus reliably workable.

[0075] Referring to FIG. 1, a schematic of an overmolding apparatus 100 is shown. The overmolding apparatus 100 includes a manufactured bottom mold 102 configured to form-fit outside shape of an object of interest 112, e.g., a molded pulp, e.g., an egg carton. The overmolding apparatus 100 further includes an optional layer of a primer or bonding agent 110 (e.g., Chitosan/ AcOH). In cases where the object of interest 112 is made of cellulose-based material, the optional layer of primer or bonding agent 110 can be avoided. However, where the object of interest 112 is made of a non-cellulose-based material, the optional layer of primer or bonding agent 110 may be necessary. The overmolding apparatus 100 further includes a layer of CNF/CMC 108 that is placed on top of either the object of interest 112 or the layer of primer or bonding agent 112. The layer of CNF/CMC 108 is placed down in the form of a sheet over the aforementioned structure (i.e., just the object of interest 112 or the combination of the object of interest 112 and the layer of primer or bonding agent 110). Additionally, the overmolding apparatus 100 includes a manufactured top mold 104 configured to form-fit the above-described structure (i.e., the combination of the object of interest 112 and the layer of CNF/CMC 108 or the combination of the object of interest 112, the layer of primer or bonding agent 110, and the layer of CNF/CMC 108). The top mold 104 and the bottom mold 102 provide a sandwich-like configuration for the overmolding apparatus 100 as shown in FIG. 1, thereby providing a predetermined molding pressure and temperature to the structure shown in the overmolding apparatus 100 of FIG. 1.

[0076] One challenge in forming a layer of CNF/CMC 108 onto an object of interest 112 for any of the above-enumerated benefits is removal of water while retaining the applied shape. Thus, in relationship to the mold halves (i.e., the bottom mold 102 and the top mold 104) shown in FIG.

1, at least the top mold 104 is manufactured with holes 106 provided therein to allow escaping of water molecules during the molding operation. In addition, the bottom mold 102 can optionally be provided with holes 106 for improved drying.

[0077] An example of the process of preparing the CNF/CMC paste shown in the overmolding apparatus 100 of FIG. 1 is described. First, a BRAB ENDER mixer is used to make a CNF/CMC paste (with a solid concentration of about 18 wt.% in a solution, e.g., water or other solutions as known to a person having ordinary skill in the art, however a range of about 10% to about 30% is also within the scope of the present disclosure). Specifically, Carboxymethyl cellulose sodium salt powder (e.g., CMC) was purchased from ALFA AES AR (Lot #R07E012, D.S 0.69, q = 660 mPa-s at 1% v/v at 25 °C, Mw - 150,000 to 180,000). Next, mechanically fibrillated CNFs produced at the PROCESS DEVELOPMENT CENTER (PDC) were bought from UNIVERSITY OF MAINE, Orono, ME, USA with a solids concentration of -23.5 wt.% (Batch #122) in water. CNF/CMC pastes with a solid concentration of about 18 wt.% were prepared using a high shear torque mixer (Plasti-Corder PL 2100 Electronic Torque Rheometer, C. W. BRABENDER, South Hackensack NJ) equipped with Banbury-type mixing blades. The CNF/CMC pastes were prepared by first adding 52 g of CNF with a solid concentration of about 23.5 wt % into the mixer. The added CNF was mixed at 120 rpm and a temperature of 60 °C until the output torque curve reached a plateau. The required amount of processing aid was gradually added until a ratio of 0.1 : 1 was reached (CMC/CNF, both dry weight), however, above-mentioned ratios are within the ambit of the present disclosure. Water was also added as needed into the paste to control the final solids concentration and replace the lost water during mixing (-1 wt.% solids increase for a mixing time of 40 min). During mixing, the rotor speed was held at 120 rpm. The paste was mixed until the CMC was fully incorporated into the paste which was signaled by a constant rise in torque followed by a plateau region. Utilizing this example method, an average -66 grams of CNF/CMC paste could be processed in less than an hour. The above description of making the CNF/CMC paste is only one example, and no limitation is intended thereby.

[0078] Once the paste of CNF/CMC is made, using a rolling pin or slip roller, the paste is pressed into a CNF/CMC film with a predetermined thickness (about 1 mm). Next, the inner wall of the object of interest, e.g., a molded pulp, e.g., an egg carton, is processed with a primer or bonding agent. Towards this end, the inner wall is smeared with chitosan/10% acetic acid (aq)/water solution, weight ratio 2:8:90, however, other primers or bonding agents known to a person having ordinary skill in the art are also within the scope of the present disclosure.

[0079] Next, the thin film of CNF/CMC as described above is placed on the top of the inner side of the tray, use fingers to flatten the folded part, remove any leftover materials with a blade. Care must be taken to properly squeeze out the air between the wet sheet and the inner wall of the tray. Additionally, some water can be sprayed on the top of the wet sheet and smeared evenly. [0080] Next, the processed object is placed inside the mold halves. The mold halves are then secured with a securement providing a predetermined mold pressure to the structure. Next the secured mold haves are placed in an oven heated to about 90 °C for about 6 hrs, depending on the object of interest 112 (e.g., a molded pulp).

[0081] Referring to FIG. 2, a flow of the above-referenced steps is provided up to removal from the oven.

[0082] Referring to FIG. 3, a photograph of an example of the mold halves is shown with holes provided in both halves for improved breathability of the molding process. [0083] For improved adhesion of CNF/CMC to the object, starch glue can be smeared on the edge of object.

[0084] The overmolded object of interest with CNF/CMC was tested for various parameters. Referring to FIG. 4, a bar graph of Water vapor transport rate (WVTR) in g/cm²-d vs. time in days is provided showing results from coated molded pulp (MP) in dry form vs. coated MP in wet form vs. uncoated MP in dry form vs. uncoated MP in wet form.

[0085] The added strength due to the overmolding of the CNF/CMC layer is demonstrated with reference to FIG. 5. FIG. 5 is a graph of stress (MPa) vs strain (%) curves for coated and uncoated MP samples in uniaxial tensile testing. In all coated sample cases, it is observed from the figure a much higher stress (about 16-17 MPa) before plastic deformation occurs in the form of breakage as compared to uncoated sample which can only withstand about 5-6 Mpa prior to plastic deformation. Thus, the difference between the two scenarios is about 3X.

[0086] Referring to FIGs. 6 A and 6B load carrying capability of the overmolded pulp is demonstrated. FIG. 6A is a graph of load (N) vs. strain for five uncoated samples; while FIG. 6B is the same graph for the same samples but coated. The crushing force for the coated samples is about 400 N whereas the crushing force for uncoated samples is about 250 N. Thus, the difference between the two scenarios is about 3X. For both cases, the composition and thickness of the coating and MP is provided in Table 1.

Table 1 - Composition of coating for FIGs. 4, 5, and 6A-6B thickness/mm UTS/MPa

CNF/CMC coating 0.2 ~110 molded pulp 1.55 ~6 coated MP 1.75 ~17

[0087] As discussed above, one of the advantages of the CNF/CMC coating is a barrier to grease. A grease resistant test was performed with TAPPI T559 Kit. Table 2 provides mixture of reagents for preparing the kit solution. Table 2 - Mixture of reagents for preparing kit solution for grease testing

Ki No. Castor Oil, Toluene, n-heptane. g mL mL

1 969.0 0 0

2 872.1 50 50

3 775.2 100 100

4 678.3 150 150

5 581.4 200 200

6 484.5 250 250

7 387.6 300 300

8 290.7 350 350

9 193.8 400 400

10 96.9 450 450

11 0 500 500

12 0 450 550

[0088] In order to generate the top and bottom mold haves shown in FIG. 1, a 3-dimensional digital map including depth information from an object of interest is needed. This digital pattern can be generated via a 3-dimensional laser scanning process, known to a person having ordinary skill in the art, an example of which is provided in U.S. Pat. No. 10,353,055 to Moon et al, incorporated by reference in its entirety into the present disclosure.

[0089] Once the 3-dimensional digital map has been generated, using a translation software, a 3- dimensional printing image of the pattern is generated for mold halves with the aforementioned holes placed therein. Next, the mold halves are generated for the method of the present disclosure.

[0090] While the present disclosure is mainly related to an overmolding process of an object of interest that has already been molded (e.g., an egg carton), i.e., an already molded object of interest is placed in the overmolding apparatus shown in FIG. 1, in order to improve the durability, strength, and general quality of the object of interest, the teachings of the present disclosure can also be applied to co-molding an object of interest with CNF/CMC at the same time, instead of a post-processing approach. In this embodiment, a co-molding apparatus similar to the one shown in FIG. 1 is provided having a top half and a bottom half that is dimensioned for the object of interest. A moldable material constituting raw material for the object of interest is then placed into the bottom half of the mold. Next, a layer or laying a sheet of a mixture of CNF/CMC is placed on to the moldable material, e.g., by spreading said CNF/CMC onto the moldable material. Next, the top half of the mold is placed onto the CNF/CMC layer. Thereafter, a predetermined pressure is applied between the top and bottom halves of the mold while applying a predetermined amount of heat to the mold, to thereby simultaneously mold both the object of interest and the CNF/CMC layer thereon. After a predetermined amount of time, the molded object of interest with the CNF/CMC layer formed thereon is then removed from the mold.

[0091] It should be noted that the mixture of CNF/CMC according to the present disclosure may further include additives selected from the group consisting of polyvinylalcohol, starch, polyacrylamides, polyaziridine, polyamidoamine-epichlorohydrins, polycarbodiimides, ammonium zirconium carbonate, alkyl ketene dimers, silanes, anhydrides, and a combination thereof.

[0092] In all embodiments of the present disclosure, an item of interest may be placed in the object of interest with the layer of CNF/CMC formed thereon via the overmolding process or the co-molding process, and further lidding the item of interest with a pliable wrap. The pliable wrap is selected from the group consisting of polyethylene terephthalate (PET), polypropylene, polylactic acid (PLA), and a combination thereof. The pliable wrap may also be made from low-density polyethylene (LDPE), wherein LDPE includes linear low-density polyethylene as an additive. The pliable wrap is made further be alternatively be made from only bio-degradable material. [0093] Those having ordinary skill in the art will recognize that numerous modifications can be made to the specific implementations described above. The implementations should not be limited to the particular limitations described. Other implementations may be possible.

Claims

Claims:

1. A method of overmolding an object of interest with a protective coating, comprising: receiving a mold having a top half and a bottom half dimensioned for an object of interest; placing the object of interest into the bottom half of the mold; spreading a layer or laying a sheet of a mixture cellulose nanofibril (CNF) and carboxymethyl cellulose (CMC) on to the object of interest; placing the top half of the mold onto the CNF/CMC layer; applying a predetermined pressure between the top and bottom halves of the mold; applying a predetermined amount of heat to the mold, to thereby molding the CNF/CMC mixture onto the object of interest; removing the object of interest with the layer of CNF/CMC formed thereon from the mold after a predetermined amount of time.

2. The method of claim 1, wherein the object of interest is a molded pulp.

3. The method of claim 2, wherein the molded pulp is a food carton.

4. The method of claim 2, wherein the molded pulp is a pharmaceutical carton.

5. The method of claim 1, wherein the mixture of CNF/CMC has a CMC to CNF weight ratio range of between about 0.03:1 to about 0.3:1.

6. The method of claim 5, wherein the weight ratio range is between about 0.03: 1 to about 0.2:1.

7. The method of claim 5, wherein the weight ratio range is between about 0.03: 1 to about 0.1:1.

8. The method of claim 5, wherein the weight ratio range is between about 0.05: 1 to about 0.2:1.

9. The method of claim 5, wherein the weight ratio range is between about 0.05: 1 to about 0.15:1.

10. The method of claim 5, wherein the weight ratio range is between about 0.1:1 to about 0.2:1.

11. The method of claim 5, wherein the weight ratio range is between about 0.1:1 to about 0.15:1.

12. The method of claim 1, wherein the CNF/CMC coated object of interest can withstand about 3X higher stress as compared to an uncoated object of interest prior to onset of plastic deformation.

13. The method of claim 1, wherein the CNF/CMC coated object of interest can withstand about 1.6X higher load as compared to an uncoated object of interest prior to being crushed.

14. The method of claim 1, wherein the CNF/CMC coated object of interest has a kit grease resistance value of 6 to 8 as compared to an uncoated object of interest with a kit value of 1.

15. The method of claim 1, wherein the CNF/CMC coated object of interest has 20% or more higher resistance to moisture as compared to an uncoated object of interest as measured by WVTR.

16. The method of claim 1, wherein the top half of the mold includes a plurality of through- holes.

17. The method of claim 16, wherein the wherein the bottom half of the mold includes a plurality of through-holes.

18. The method of claim 1, wherein the predetermined pressure is about 1.5 KPa.

19. The method of claim 1, wherein the predetermined amount of heat causes the mold to reach between about 70 °C and about 110 °C.

20. The method of claim 1, prior to spreading the layer of mixture of CNF/CMC, further comprising applying a layer of a primer or bonding agent to the object of interest.

21. The method of claim 20, the primer or bonding agent comprises chitosan, cationic starch, and starch.

22. The method of claim 1, further comprising: placing an item of interest in the object of interest with the layer of CNF/CMC formed thereon; and lidding the item of interest with a pliable wrap.

23. The method of claim 22, wherein the pliable wrap is selected from the group consisting of polyethylene terephthalate (PET), polypropylene, polylactic acid (PLA), and a combination thereof.

24. The method of claim 22, wherein the pliable wrap is made from low-density polyethylene (LDPE).

25. The method of claim 24, wherein LDPE includes linear low-density polyethylene as an additive.

26. The method of claim 22, wherein the pliable wrap is made from a bio-degradable material.

27. The method of claim 1, wherein the mixture of CNF/CMC further includes additives selected from the group consisting of polyvinylalcohol, starch, polyacrylamides, poly aziridine, poly amidoamine-epichlorohy drins, polycarbodiimides, ammonium zirconium carbonate, alkyl ketene dimers, silanes, anhydrides, and a combination thereof.

28. A method of co-molding an object of interest with a protective coating, comprising: receiving a mold having a top half and a bottom half dimensioned for an object of interest; placing a moldable material constituting raw material for the object of interest into the bottom half of the mold; spreading a layer or laying a sheet of a mixture of cellulose nanofibril (CNF) and carboxymethyl cellulose (CMC) on to the moldable material; placing the top half of the mold onto the CNF/CMC layer; applying a predetermined pressure between the top and bottom halves of the mold; applying a predetermined amount of heat to the mold, to thereby simultaneously molding both the object of interest and the CNF/CMC layer thereon; and removing the molded object of interest with the CNF/CMC layer formed thereon from the mold after a predetermined amount of time.

29. The method of claim 28, wherein the moldable material for the object of interest is a slurry of a fibrous pulp.

30. The method of claim 28, wherein the mixture of CNF/CMC further includes additives selected from the group consisting of polyvinylalcohol, starch, polyacrylamides, poly aziridine, poly amidoamine-epichlorohy drins, polycarbodiimides, ammonium zirconium carbonate, alkyl ketene dimers, silanes, anhydrides, and a combination thereof.

31. The method of claim 28, wherein the object of interest is a molded pulp.

32. The method of claim 31, wherein the molded pulp is a food carton. The method of claim 31, wherein the molded pulp is a pharmaceutical carton. The method of claim 28, wherein the mixture of CNF/CMC has a CMC to CNF weight ratio range of between about 0.03:1 to about 0.3:1. The method of claim 28, wherein the weight ratio range is between about 0.03:1 to about 0.2:1. The method of claim 28, wherein the weight ratio range is between about 0.03:1 to about 0.1:1. The method of claim 28, wherein the weight ratio range is between about 0.05:1 to about 0.2:1. The method of claim 28, wherein the weight ratio range is between about 0.05:1 to about 0.15:1. The method of claim 28, wherein the weight ratio range is between about 0.1:1 to about 0.2:1. The method of claim 28, wherein the weight ratio range is between about 0.1:1 to about 0.15:1. The method of claim 28, wherein the CNF/CMC coated object of interest can withstand about 3X higher stress as compared to an uncoated object of interest prior to onset of plastic deformation. The method of claim 28, wherein the CNF/CMC coated object of interest can withstand about 1.6X higher load as compared to an uncoated object of interest prior to being crushed. The method of claim 28, wherein the CNF/CMC coated object of interest has a kit grease resistance value of 6 to 8 as compared to an uncoated object of interest with a kit value of 1. The method of claim 28, wherein the CNF/CMC coated object of interest has 20% or more higher resistance to moisture as compared to an uncoated object of interest as measured by WVTR. The method of claim 28, wherein the top half of the mold includes a plurality of through- holes. The method of claim 28, wherein the predetermined pressure is between about 10 KPa to about 10 MPa.

47. The method of claim 28, wherein the predetermined amount of heat causes the mold to reach between 50 °C and 400 °C.

48. The method of claim 28, prior to spreading the layer of mixture of CNF/CMC, further comprising applying a layer of a primer or bonding agent to the object of interest.

49. The method of claim 48, the primer or bonding agent comprises chitosan, cationic starch, and starch.

50. The method of claim 28, further comprising: placing an item of interest in the object of interest with the layer of CNF/CMC formed thereon; and lidding the item of interest with a pliable wrap.

51. The method of claim 50, wherein the pliable wrap is selected from the group consisting of polyethylene terephthalate (PET), polypropylene, polylactic acid (PLA), and a combination thereof.

52. The method of claim 50, wherein the pliable wrap is made from low-density polyethylene (LDPE).

53. The method of claim 52, wherein LDPE includes linear low-density polyethylene as an additive.

54. The method of claim 50, wherein the pliable wrap is made from a bio-degradable material.