Molded articles made from pulp compositions providing grease and water resistance

Abstract

This invention relates to molded articles made from pulp compositions possessing grease and water resistance properties. Food-safe compositions and articles thereof possessing grease and water resistance properties are provided, comprising petroleum wax-based aqueous emulsions, food-safe coating formulations, and alkyl ketene dimers (AKD), wherein the compositions exhibit grease and water resistance properties and are free of fluorinated compounds. Methods for manufacturing the compositions are provided, as well as methods for using the compositions to form pulp molded articles such as food-safe containers and other pulp-based food packaging and utensils.

Description

[0001] This application is a divisional application of the following application: filed on April 3, 2020, application number 202080041296.5, entitled "Molded article made of pulp composition with grease and water resistant properties".

[0002] Cross-reference to related applications

[0003] This international application claims priority to U.S. Application No. 16 / 839,340, filed April 3, 2020, which in turn claims priority to U.S. Provisional Application No. 62 / 829,368, filed April 4, 2019, with the U.S. Patent and Trademark Office. The disclosure of the latter is incorporated herein by reference in its entirety. Technical Field

[0004] This invention relates to pulp molded articles for containing food, and more particularly to such pulp molded articles having oil and water resistance properties. Background of the Invention

[0005] In the foodservice packaging industry, molded pulp products are manufactured to be used as food packaging materials to safely contain food for consumption in or from foodservice operations. These products must be food-safe and ideally resistant to grease and water to prevent food leakage or contamination of unwanted surfaces or items. For many years, the foodservice packaging industry has used FDA-approved chemicals to provide that functional resistance. However, these currently used chemicals are fluorinated compounds.

[0006] Despite FDA approval, several NGOs have recently conducted research to raise awareness of fluorinated compounds and their impact on human health. Furthermore, the Biodegradable Products Association (a leading certification body for compostability) has set total fluoride limits effective January 1, 2020, aimed at eliminating intentionally added fluorinated compounds. Efforts are underway to demonstrate that these compounds are bioaccumulative and thus "pool" in compost applicable to crops, and therefore usable by plants and their fruits. Consequently, industry desires and needs to identify alternative wet-end chemicals that do not use fluorinated compounds but deliver similar oil and water resistance. Summary of the Invention

[0007] This invention relates to a chemical composition, a manufacturing method, and a pulp molded article made therefrom for containing food, wherein no fluorinated compounds are present.

[0008] In one embodiment of the invention, a pulp molding article is provided. The article comprises natural fibers, alkyl ketene dimer (AKD), a food-safe coating formulation, and a petroleum wax-based aqueous emulsion.

[0009] In one embodiment of the invention, the pulp molding article comprises at least 95% natural fibers, at least 0.15% alkyl ketene dimer (AKD), at least 0.1% petroleum wax-based aqueous emulsion, and less than 1% vinyl acetate-vinyl alcohol polymer, wherein the article exhibits oil and grease resistance and is suitable for food contact.

[0010] In one embodiment of the invention, the article comprises: 96% to 99.65% natural fiber, 0.15% to 1.1% alkyl ketene dimer (AKD), 0.1% to 1.9% food-safe coating formulation, and 0.1% to 1% petroleum wax-based aqueous emulsion, wherein the percentages are weight percentages based on the dry weight of the formulation of the article.

[0011] In other embodiments of the invention, the article is molded from a pulp composition. The article is formed into a tray, container, plate, bowl, vessel, lid, or cup. The article is compostable in an industrial composting facility. The article has a thickness of less than 2 mm. The article has a thickness of at least 0.5 mm.

[0012] In one embodiment of the present invention, an additive composition is provided. The additive composition comprises a food-safe coating formulation, a petroleum wax-based aqueous emulsion, and an alkyl ketene dimer (AKD).

[0013] In one embodiment of the invention, the additive composition comprises a petroleum wax-based aqueous emulsion and an alkyl ketene dimer (AKD).

[0014] In one embodiment of the invention, a pulp-based composition is provided. The pulp-based composition comprises 0.1 wt% to 10 wt% of a petroleum wax-based aqueous emulsion, 0.1 wt% to 10 wt% of a food-safe coating formulation, 0 wt% to 0.5 wt% of a cationic polymer, 0.1 wt% to 10 wt% of an alkyl ketene dimer, and 69.5 wt% to 99.7 wt% of pulp, wherein the weight percentages are based on the total weight of the pulp-based composition.

[0015] The further applicability of the invention will become apparent from the detailed description provided below. It should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are for illustrative purposes only and are not intended to limit the scope of the invention. Attached Figure Description

[0016] The invention will be more fully understood from the detailed description and accompanying drawings. The drawings are not necessarily to scale, and wherein:

[0017] Figure 1 A process flow diagram is provided to illustrate one embodiment of the present invention. Detailed Implementation

[0018] The following description of embodiments of the present invention is merely exemplary in nature and is in no way intended to limit the invention, its application, or its uses. The following description is provided by way of example only for the purpose of providing a disclosure of the implementability of the invention, but does not limit the scope or nature of the invention.

[0019] In one embodiment of the invention, an additive composition is provided that is resistant to grease and water without the use of fluorinated compounds. The additive composition is used in the wet end of a paper pulping machine or process. The term "wet end" is a general term for the portion of a paper machine or process involving pulp containing fibers, fillers, or other additives. The "dry end" of a paper machine is generally the place where the paper roll is formed. A rough boundary between the wet end and the dry end is usually drawn at the wet press, the final point where water is extracted from the wet paper web. An exception to this rule is the sizing press, as the sizing press process can be closely associated with what happens in the wet end. The beginning of the wet end is generally considered to be at the main refiner system, as most papermaking chemicals are added after that point.

[0020] According to one embodiment of the invention, the additive composition comprises, or is substantially composed of, a food-safe coating formulation, a petroleum wax-based aqueous emulsion, and an alkyl ketene dimer (AKD). This additive composition is described herein and Figure 1 This is referred to as "additive composition 1".

[0021] Additive composition 1 is an emulsion of the following substances: 35% to 55% by weight of a food-safe coating formulation, 15% to 35% by weight of a petroleum wax-based aqueous emulsion, and 20% to 40% by weight of AKD, wherein the weight percentages are based on the total weight of the additive composition; and it produces a final emulsion with 15% to 35% by weight of total active solids, of which 1% to 20% by weight is the food-safe coating formulation, 1% to 20% by weight is the wax emulsion, and 1% to 10% by weight is AKD. These chemicals are emulsified for a period of time to ensure that the emulsion remains in suspension.

[0022] Preferably, additive composition 1 is an emulsion of the following substances: 40% to 50% by weight of a food-safe coating formulation, 20% to 30% by weight of a petroleum wax-based aqueous emulsion, and 25% to 35% by weight of AKD, wherein the weight percentages are based on the total weight of the additive composition; and it produces a final emulsion with 20% to 30% by weight of total active solids, of which 8% to 12% by weight is the food-safe coating formulation, 8% to 12% by weight is the wax emulsion, and 4% to 6% by weight is AKD. These chemicals are emulsified for a period of time to ensure that the emulsion remains in suspension.

[0023] According to another embodiment of the invention, the additive composition comprises, is substantially composed of, or is composed of, a petroleum wax-based aqueous emulsion and an alkyl ketene dimer (AKD). This additive composition is described herein and Figure 1 It is referred to as "additive composition 2" in Chinese.

[0024] Additive composition 2 is an emulsion of 50% to 70% by weight of a petroleum wax-based aqueous emulsion and 30% to 50% by weight of AKD, wherein the weight percentages are based on the total weight of the additive composition; and produces a final emulsion with 10% to 35% by weight of total active solids, of which 5% to 20% by weight is a wax emulsion and 1% to 20% by weight is AKD. These chemicals are emulsified for a period of time to ensure that the emulsion remains in suspension.

[0025] Preferably, additive composition 2 is an emulsion of 55% to 65% by weight of a petroleum wax-based aqueous emulsion and 35% to 45% by weight of AKD, wherein the weight percentages are based on the total weight of the additive composition, and produce a final emulsion with 15% to 30% by weight of total active solids, of which 10% to 15% by weight is a wax emulsion and 8% to 12% by weight is AKD. These chemicals are emulsified for a period of time to ensure that the emulsion remains in suspension.

[0026] The additive compositions of the present invention exhibit oil and water resistance properties, and no fluorinated compounds are present in the additive compositions.

[0027] Examples of petroleum wax-based aqueous emulsions suitable for use in the compositions are cationic emulsions of paraffin, and more particularly, cationic emulsions of fully refined paraffin. Commercially available suppliers of petroleum wax-based aqueous emulsions include, but are not limited to, Walker Industries' WE20, Michelman, Inc.'s HY708, etc.

[0028] Examples of food safety coating formulations are coating formulations comprising a vinyl acetate-vinyl alcohol polymer. Preferably, the coating formulation has a component selected from: vinyl acetate-vinyl alcohol polymer, isothiazolinone, polyalkylene glycol, and combinations thereof. Examples of commercially available food safety coating formulations and suppliers include, but are not limited to, MC525 from Michelman, Inc.

[0029] Retention aids are used to retain small fibers (fine particles), fillers, and other small particles on the finished sheet in a papermaking system, and to help remove more water during the forming process, thereby reducing the dewatering load on the dryer of the papermaking machine or system. Examples of retention aids are cationic polymers, more preferably cationic polyacrylamide. Commercially available retention aids and their suppliers include, but are not limited to, Bufloc 5321 from Buckman Laboratories International, Inc., Solenis International LLC, and others.

[0030] Examples of sizing agents suitable for use in the compositions are alkyl ketene dimers (AKD). Suppliers of commercially available sizing agents include, but are not limited to, Ares Chemical, Kemira Chemicals, etc.

[0031] Other additives may be present in the composition or may be added during the process. Examples of other additives include, but are not limited to: retention aids, sizing agents, pigments, dyes, other colorants, and combinations thereof.

[0032] Refer to the attached diagram. Figure 1 An embodiment of the process according to the invention is illustrated. Pulp stock (e.g., about 3% dry weight pulp and 97% water) is fed into a dense bleached pulp tank 50 (“Tank 1”). Dense pulp is added from the pulp tank 50 to a mixing tank 60. Examples of pulp types used in the invention include, but are not limited to, sugarcane fiber, bagasse, bamboo, wheat straw, and miscanthus.

[0033] Additive 1 is a petroleum wax-based aqueous emulsion. Additive 1 is added to mixing tank 60 simultaneously with the addition of dense pulp. After completing the first two addition steps, the mixer in mixing tank 60 is turned on for a period of time, for example, several minutes.

[0034] Additive 2 is a food-safe coating formulation. Additive 2 from tank 20 is added to mixing tank 60 and mixed for a period of time, such as a few minutes. Additive 4 is AKD. Additive 4 from tank 30 is added to mixing tank 60 and mixed for a few minutes. Fresh (tap) water from the water circulation tank in tank 80 is added to mixing tank 60. Note that the mixing period may vary depending on the tank size, pulp viscosity, fiber size, and other process parameters.

[0035] Additive 3 is a retention aid. Additive 3 is added to tank 40 simultaneously with the addition of fresh water. After adding fresh water and additive 3, mixing tank 60 is used for mixing. After mixing, the finished mixed pulp is pumped from mixing tank 60 to forming tank 70.

[0036] The plate can maintain a top and bottom temperature of 110°C.

[0037] In an alternative method, additives 1, 2 and 4 are blended together as additive composition 1 for tank 5 and subsequently added to the pulp slurry in the tank, or added directly to the tube before any other additives and combined after being added to the tank.

[0038] In another alternative method, additives 1 and 4 are blended together as additive composition 2 for tank 5 and subsequently added to the pulp slurry in the tank, or added directly to the tube before any other additives and combined after being added to the tank.

[0039] In one embodiment of the invention, a pulp-based composition is provided. The pulp-based composition comprises: 0.1 wt% to 10 wt% of a petroleum wax-based aqueous emulsion, 0.1 wt% to 10 wt% of a food-safe coating formulation, 0 wt% to 0.5 wt% of a cationic polymer, 0.1 wt% to 10 wt% of an alkyl ketene dimer, and 69.5 wt% to 99.7 wt% of pulp, wherein the weight percentages are based on the total weight of the pulp-based composition.

[0040] The resulting pulp-based composition can then be molded or formed into pulp molded products that are safe for contact with or containment of food (also known as "food safety"). "Food safety" generally refers to the safety of food for human consumption.

[0041] One advantage of the compositions of the present invention is that the chemical compositions do not use fluorinated compounds to achieve acceptable oil and water resistance. The fluoride-free chemical compositions of the present invention achieve acceptable oil resistance for most food applications in food service without safety risks.

[0042] Examples of pulp molded articles used to hold food or beverages include, but are not limited to, trays, containers, clam shells, lids, cups, plates, bowls, utensils such as serving or eating utensils, or combinations thereof.

[0043] In addition, the elimination of fluorinated compounds from the packaging reduces the source of these compounds in the composting process, which will reduce the risk of human exposure.

[0044] In one embodiment of the present invention, a food safety article is provided, the article comprising: natural fibers, alkyl ketene dimer (AKD), a food safety coating formulation, and a petroleum wax-based aqueous emulsion. The article does not contain fluorinated compounds.

[0045] Preferably, the natural fiber is sugarcane fiber. The sugarcane fiber may be bleached / whitened or unbleached. Other natural fibers are contemplated to be used according to the invention.

[0046] In another embodiment of the invention, the article comprises: 96% to 99.65% by weight of natural fibers, 0.15% to 1.1% by weight of alkyl ketene dimer (AKD), 0.1% to 1.9% by weight of a food-safe coating formulation, and 0.1% to 1% by weight of a petroleum wax-based aqueous emulsion, wherein the percentages are weight percentages based on the dry weight of the formulation of the article. The article is a food-safe article molded from a pulp composition. The article exhibits oil and water resistance.

[0047] The article can be of various shapes and sizes. Preferably, the thickness of the article is less than 2 mm. Preferably, the thickness of the article is at least 0.5 mm.

[0048] A feature of the present invention is that the article is compostable in an industrial composting facility.

[0049] Therefore, those skilled in the art will readily understand that the present invention allows for a wide range of practical applications. Many embodiments and modifications of the invention, in addition to those described herein, as well as numerous variations, modifications, and equivalent arrangements, will be apparent or reasonably suggested by the invention and its foregoing description without departing from the spirit or scope of the invention. Therefore, while the invention has been described in detail herein with respect to its preferred embodiments, it should be understood that this disclosure is merely illustrative and exemplary, and is made solely for the purpose of providing a complete and implementable disclosure of the invention. The foregoing disclosure is not intended or should be construed as limiting the invention or otherwise excluding any such other embodiments, modifications, variations, modifications, and equivalent arrangements.

Claims

1. A pulp article, the article comprising: Natural fibers, Alkyl ketene dimer (AKD). Food safety coating formulations, and Petroleum wax-based aqueous emulsion, The pulp article is made from a pulp-based composition comprising: 0.1% to 10% by weight of petroleum wax-based aqueous emulsions, Food safety coating formulations ranging from 0.1% to 10% by weight. 0% to 0.5% by weight of cationic polymers, 0.1% to 10% by weight of alkyl ketene dimers, and Pulp ranging from 69.5% to 99.7% by weight. The weight percentages are based on the total weight of the pulp-based composition.

2. The pulp article according to claim 1, wherein the pulp article is molded, formed, or both.

3. The pulp article of claim 1, wherein the pulp article does not contain fluorinated compounds.

4. The pulp product according to claim 1, wherein the pulp product is food-safe.

5. The pulp product according to claim 1, wherein the natural fiber is sugarcane fiber.

6. The pulp product according to claim 5, wherein the sugarcane fiber is bleached or white sugarcane fiber.

7. The pulp product according to claim 5, wherein the sugarcane fiber is unbleached sugarcane fiber.

8. The pulp article of claim 1, wherein the food-safe coating formulation comprises a component selected from: vinyl acetate-vinyl alcohol polymer; isothiazolinone; polyalkylene glycol; and combinations thereof.

9. An additive composition comprising: A food safety coating formulation, wherein the food safety coating formulation is present in an amount of 35% to 55% by weight, based on the total weight of the additive composition; A petroleum wax-based aqueous emulsion, wherein the petroleum wax-based aqueous emulsion is present in an amount of 15% to 35% by weight, based on the total weight of the additive composition; and Alkyl ketene dimer (AKD), wherein the AKD is present in an amount of 20% to 40% by weight based on the total weight of the additive composition; The additive composition is used in the wet end of a paper pulping machine or process.

10. The additive composition of claim 9, wherein the additive composition further comprises a component selected from: retention aids, sizing agents, pigments, dyes, other colorants, and combinations thereof.

11. The additive composition according to claim 9, wherein the additive composition is in the form of an emulsion.

12. The additive composition of claim 11, wherein the emulsion comprises 15% to 35% by weight of total active solids.

13. The additive composition of claim 12, wherein the total active solids comprise 1% to 20% by weight of a food-safe coating formulation, 1% to 20% by weight of a petroleum wax-based aqueous emulsion, and 1% to 10% by weight of AKD.

14. The additive composition according to claim 9, wherein the additive composition exhibits oil and water resistance, and wherein no fluorinated compounds are present in the additive composition.

15. A pulp-based composition, said pulp-based composition comprising: 0.1% to 10% by weight of petroleum wax-based aqueous emulsions, Food safety coating formulations ranging from 0.1% to 10% by weight. 0% to 0.5% by weight of cationic polymers, 0.1% to 10% by weight of alkyl ketene dimers, and Pulp ranging from 69.5% to 99.7% by weight. The weight percentages are based on the total weight of the pulp-based composition.

16. A method of manufacturing a pulp-based composition, the method comprising adding the pulp-based composition according to claim 15 to the wet end of a paper pulping machine or process.

17. A method of using a pulp-based composition, the method comprising molding or shaping the pulp-based composition according to claim 15 into a food-safe shaped article.

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