Melt-processible and foamable cellulose acetate formulations containing natural fillers

Abstract

This application discloses a foamable composition comprising 30-92 wt% cellulose acetate, 5-30 wt% at least one plasticizer, 3-40 wt% at least one natural filler, and 0-9 wt% at least one physical blowing agent. This composition can be used to produce biodegradable foams and foam articles with density, cell size, mechanical, and thermal properties suitable for low- and medium-density foaming applications.

Description

[Background technology]

[0001] Foam materials are useful in applications such as thermal insulation, food packaging, non-food packaging, and sound insulation. Many food service items are disposable, intended to be disposed of after the food package is opened or the food is served. One commercially important material used to manufacture foam food packaging items is polystyrene. However, polystyrene is neither compostable nor biodegradable. Furthermore, some municipalities, states, and countries have enacted or are considering enacting bans on the use of polystyrene-based foams. In addition to polystyrene's non-biodegradability, many polystyrene foams utilize talc as an inorganic physical nucleating agent to initiate foam cell formation. There may be health and safety concerns regarding the use of talc in products intended for food contact applications.

[0002] Cellulose acetate foams are biodegradable and can be used as an alternative to polystyrene foam. However, cellulose acetate foams require a suitable density (0.400 g / cm for low density applications). 3 or less, or 0.400 g / cm for medium density applications 3 exceeding 1.0 g / cm 3 ) and exhibit good thermal and mechanical properties. Cellulose acetate-based foams must be processable on commercially available extrusion equipment and, desirably, be capable of being thermoformed on commercially available thermoforming equipment. Natural fillers can also be biodegradable and function as physical nucleating agents during the foaming process. Furthermore, because natural fillers are hygroscopic, they can function as water carriers, which act as physical blowing agents during the foaming process and help reduce the density of the resulting foam. Because natural fillers are less expensive than cellulose acetate resins, they can simultaneously reduce the raw material costs of cellulose acetate-based foamable compositions while improving foaming properties by functioning as physical nucleating agents and / or physical blowing agents. Summary of the Invention

[0003] The present application discloses a foamable composition comprising 30-92 wt% cellulose acetate, 5-30 wt% at least one plasticizer, 3-40 wt% at least one natural filler, and 0-9 wt% at least one physical blowing agent, where wt% is based on the total weight of all components of the composition. The foamable composition has a density of 0.040-0.600 g / cm. 3 It is possible to form a biodegradable cellulose acetate foam having an average foam cell size of 20 to 600 microns and an appearance that is easily distinguishable from polystyrene foam. The biodegradable cellulose acetate foam can be formed into articles.

[0004] definition It should be understood that the following is not intended to be an exhaustive list of defined terms. Other definitions may be provided in the preceding description, for example, when accompanying the use of a defined term in context.

[0005] As used herein, the terms "a," "an," and "the" mean one or more.

[0006] As used herein, the terms "comprising," "comprises," and "comprise" are open-ended transitional phrases used to transition the subject matter listed before the term to one or more elements listed after the term, and the element(s) listed after the transitional phrase are not necessarily the only elements that make up the subject matter.

[0007] Nucleating agents refer to chemical or physical materials that provide sites for cell formation in the molten formulation mixture. Nucleating agents can include chemical and physical nucleating agents. Nucleating agents can be blended with the compound introduced into the hopper of the extruder. Alternatively, nucleating agents can be added to the molten resin mixture in the extruder.

[0008] Suitable physical nucleating agents have a desirable particle size. Examples of inorganic physical nucleating agents include, but are not limited to, talc, CaCO3, mica, and mixtures of at least two of the foregoing. One representative example is Heritage Plastics HT6000 linear low-density polyethylene (LLDPE)-based talc concentrate. It has been found that biodegradable, particulate natural fillers derived from renewable organic sources can also function as effective physical nucleating agents. Examples of natural fillers that can be physical nucleating agents include, but are not limited to, pecan shell flour, walnut shell flour, wood flour, corncob flour, rice husk flour, and oat fiber powder. One representative example of an organic physical nucleating agent is oat fiber powder commercially available from Nunatural.

[0009] Suitable chemical nucleating agents decompose upon reaching chemical reaction temperatures, producing cells in the molten formulation. These small cells serve as nucleation sites for the growth of larger cells from physical or other types of blowing agents. Examples of chemical nucleating agents include, but are not limited to, citric acid or citric acid-based materials. One representative example is HYDROCEROL™ CF-40E (available from Clariant Corporation), which contains citric acid and a crystal nucleating agent.

[0010] A blowing agent refers to a physical or chemical material (or combination of materials) that acts to expand nucleation sites. Blowing agents can include chemical blowing agents, physical blowing agents, a combination thereof, or several types of chemical and physical blowing agents. Blowing agents act to reduce density by expanding cells formed in the molten compound at the nucleation sites. Blowing agents can be added to the molten resin mixture in the extruder. It has surprisingly been discovered that the hygroscopic nature of biodegradable particulate natural fillers allows them to absorb moisture and carry the absorbed water into the molten resin mixture, where they can act as a physical blowing agent.

[0011] Chemical blowing agents are materials that decompose or react to produce a gas. Chemical blowing agents can be endothermic or exothermic. Chemical blowing agents typically degrade and decompose at a specific temperature, releasing a gas. Examples of chemical blowing agents include citric acid, sodium bicarbonate, sodium carbonate, ammonium bicarbonate, and ammonium carbonate.

[0012] Examples of physical blowing agents include H2O, N2, CO2, alkanes, alkenes, ethers, ketones, argon, helium, air, or mixtures. As mentioned above, hygroscopic biodegradable natural fillers can be incorporated into the composition to absorb moisture prior to the foaming process, and then release the water to act as a physical blowing agent.

[0013] In embodiments, the cellulose acetate utilized in the present invention can be any known in the art that is biodegradable. Cellulose acetates that can be used in the present invention generally contain repeating units of the following structure:

[0014] [ka] In the formula, R 1 , R 2 and R 3are independently selected from the group consisting of hydrogen or acetyl. For cellulose esters, the substitution level is usually expressed 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 for each substitutable AGU unit. Therefore, DS can have a value between 0 and 3. Natural cellulose is a large polysaccharide with a degree of polymerization of 250 to 5,000, even after pulping and purification, so the assumption that the maximum DS is 3.0 is generally correct. Because DS is a statistical average, a value of 1 does not guarantee that every AGU has a single substituent. In some cases, unsubstituted anhydroglucose units may exist, some with two or some with three substituents, and the value will usually be a non-integer. Total DS is defined as the average number of all substituents per anhydroglucose unit. The degree of substitution per AGU can also refer to a specific substituent, such as hydroxyl or acetyl. In embodiments, n is an integer ranging from 25 to 250, or from 25 to 200, or from 25 to 150, or from 25 to 100, or from 25 to 75.

[0015] In embodiments of the present invention, the cellulose acetate has at least two anhydroglucose rings and may have at least 50 to a maximum of 500 anhydroglucose rings, or at least 50 to fewer than 150 anhydroglucose rings. The number of anhydroglucose units per molecule is defined as the degree of polymerization (DP) of the cellulose acetate. In embodiments, the cellulose ester may have an intrinsic viscosity (IV) of about 0.2 to about 3.0 deciliters / gram, or about 0.5 to about 1.8, or about 1 to about 1.5, measured at 25°C on a 0.25 gram sample in 100 ml of a 60 / 40 weight percent solution of phenol / tetrachloroethane. In embodiments, the cellulose acetate useful herein may have a DS / AGU of about 2.2 to about 2.6, and the substituted ester is acetyl.

[0016] Cellulose acetate can be produced by any method known in the art.Examples of the production process of cellulose esters are taught in Kirk-Othmer, Encyclopedia of Chemical Technology, 5th Edition, Vol. 5, Wiley-Interscience, New York (2004), pp. 394-444.The cellulose that is the starting material for producing cellulose acetate can be obtained from various grades and sources, such as cotton linters, softwood pulp, hardwood pulp, corn fiber, and other agricultural sources, and bacterial cellulose, among others.

[0017] One method for producing cellulose acetate is to esterify cellulose by mixing it with an appropriate organic acid, acid anhydride, and catalyst. The cellulose is then converted into a cellulose triester. A water-acid mixture may then be added to the cellulose triester to effect ester hydrolysis, which may then be filtered to remove gel particles or fibers. Water is then added to the mixture to precipitate the cellulose ester. The cellulose ester may then be washed with water to remove reaction by-products, followed by dehydration and drying.

[0018] The hydrolyzed cellulose triester can have three acetyl substituents. These cellulose esters can be prepared by a number of methods known to those skilled in the art. For example, cellulose esters can be prepared by the heterogeneous acylation of cellulose in a mixture of carboxylic acid and anhydride in the presence of a catalyst such as H2SO4. Cellulose triester can also be prepared by the homogeneous acylation of cellulose dissolved in a suitable solvent such as LiCl / DMAc or LiCl / NMP.

[0019] Those skilled in the art will understand that the trade term cellulose triester also includes cellulose esters that are not fully substituted with acyl groups. For example, cellulose triacetate commercially available from Eastman Chemical Company, Kingsport, Tennessee, USA, typically has a DS of about 2.85 to about 2.99.

[0020] After esterification of cellulose to triester, some of the acyl substituents can be removed by hydrolysis or alcoholysis to obtain secondary cellulose ester.As mentioned above, depending on the specific method used, the distribution of acyl substituents can be random or non-random.Also, secondary cellulose ester can be prepared directly without hydrolysis by using a limited amount of acylating reagent.This process is particularly useful when the reaction is carried out in a solvent that dissolves cellulose.All of these methods produce cellulose esters that are useful in the present invention.

[0021] In one embodiment or in combination with any of the mentioned embodiments, the cellulose acetate is a cellulose diacetate having a polystyrene equivalent number average molecular weight (Mn) of about 10,000 to about 100,000 as measured by gel permeation chromatography (GPC) using Mn equivalent to polystyrene according to ASTM D6474 using NMP as the solvent. In some embodiments, the cellulose acetate composition is a cellulose diacetate having a polystyrene equivalent number average molecular weight (Mn) of about 10,000 to about 100,000 as measured by gel permeation chromatography (GPC) using Mn equivalent to polystyrene according to ASTM D6474 using NMP as the solvent. 10,000 to 90,000, or 10,000 to 80,000, or 10,000 to 70,000, or 10,000 to 60,000, or 10,000 to less than 60,000, or 10,000 to less than 55,000, or 10,000 to 50,000, or 10,000 to less than 50,000, or 10,000 to less than 45,000, or 10,000 to 40,000, or 10,000 to 30,000, or 20,000 to less than 60,000, or 20,000 to less than 55,000, as determined by gel permeation chromatography (GPC) in accordance with D6474 or 20,000 to 50,000, or less than 20,000 to 50,000, or less than 20,000 to 45,000, or 20,000 to 40,000, or 20,000 to 35,000, or 20,000 to 30,000, or less than 30,000 to 60,000, or less than 30,000 to 55,000, or 30,000 to 50,000, or less than 30,000 to 50,000, or less than 30,000 to 45,000, or 30,000 to 40,000, or 30,000 to 35,000.

[0022] The most common commercially available secondary cellulose esters are produced by first heterogeneously acylating cellulose with an acid catalyst to form a cellulose triester. After obtaining a homogeneous solution of the cellulose triester in the corresponding carboxylic acid, the cellulose triester is then subjected to hydrolysis until the desired degree of substitution is achieved. After isolation, random secondary cellulose esters are obtained, i.e., the relative degree of substitution (RDS) at each hydroxyl is approximately equal.

[0023] Cellulose acetate useful in the present invention can be produced using techniques known in the art and can be selected from a variety of cellulose esters, such as those available from Eastman Chemical Company, Kingsport, Tennessee, USA, e.g., Eastman™ Cellulose Acetate CA398-30 and Eastman™ FE700.

[0024] In embodiments of the present invention, cellulose acetate can be produced by converting cellulose to cellulose esters using reactants obtained from recycled materials, e.g., recycled plastic-containing syngas sources. In embodiments, such reactants can be cellulose reactants, including organic acids and / or acid anhydrides used in esterification or acylation reactions of cellulose, as discussed herein.

[0025] In one embodiment of the present invention, or in combination with any of the mentioned embodiments, or in combination with any of the mentioned embodiments, there is provided a cellulose acetate composition comprising at least one regenerated cellulose acetate, the cellulose acetate having at least one substituent on an anhydroglucose unit (AU) derived from a recycled-containing material (e.g., recycled plastic-containing syngas).

[0026] The present application discloses a biodegradable cellulose acetate foam containing a biodegradable particulate natural filler, the foam having a density of 0.04 to 0.6 g / cm 3 and an average foam cell size of 20 μm to 600 μm.

[0027] In one embodiment, or in combination with any of the embodiments mentioned herein, the foam has a density of 0.04 to 0.6 g / cm 3 , or 0.04 to 0.5 g / cm 3 , or 0.04 to 0.4 g / cm 3 , or 0.04 to 0.3 g / cm 3, or 0.04 to 0.2 g / cm 3 , or 0.04 to 0.1 g / cm 3 , or 0.06 to 0.6 g / cm 3 , or 0.06 to 0.5 g / cm 3 , or 0.06 to 0.4 g / cm 3 , or 0.06 to 0.3 g / cm 3 , or 0.06 to 0.2 g / cm 3 , or 0.06 to 0.1 g / cm 3 , or 0.08 to 0.6 g / cm 3 , or 0.08 to 0.5 g / cm 3 , or 0.08 to 0.4 g / cm 3 , or 0.08 to 0.3 g / cm 3 , or 0.08 to 0.2 g / cm 3 , or 0.08 to 0.1 g / cm 3 , or 0.1 to 0.6 g / cm 3 , or 0.1 to 0.5 g / cm 3 , or 0.1 to 0.4 g / cm 3 , or 0.1 to 0.3 g / cm 3 , or 0.1 to 0.2 g / cm 3 , or 0.2 to 0.6 g / cm 3 , or 0.2 to 0.5 g / cm 3 , or 0.2 to 0.4 g / cm 3 , or 0.2 to 0.3 g / cm 3 , or 0.3 to 0.6 g / cm 3 , or 0.3 to 0.5 g / cm 3 , or 0.3 to 0.4 g / cm 3 , or 0.4 to 0.6 g / cm 3 , or 0.4 to 0.5 g / cm 3 , or 0.5 to 0.6 g / cm 3 It has a density of

[0028] In one embodiment, or in combination with any of the embodiments mentioned herein, the average foam cell size is 40 μm to 600 μm, or 50 μm to 600 μm, or 60 μm to 600 μm, or 70 μm to 600 μm, or 80 μm to 600 μm, or 90 μm to 600 μm, or 100 μm to 600 μm, or 150 μm to 600 μm, or 200 μm to 600 μm, or 250 μm to 600 μm. , or 300 μm to 600 μm, or 400 μm to 600 μm, or 500 μm to 600 μm, or 40 μm to 550 μm, or 40 μm to 500 μm, or 40 μm to 450 μm, or 40 μm to 400 μm, or 40 μm to 350 μm, or 40 μm to 300 μm, or 40 μm to 250 μm, or 40 μm to 200 μm, or 40 μm to 150 μm, or 40 μm to 100 μm.

[0029] In one embodiment, or in combination with any of the embodiments mentioned herein, the foam is made from a composition comprising: (a) 30-92 wt % cellulose acetate; (b) 5-30 wt % plasticizer; (c) 3.0-40 wt % at least one natural filler; and (d) 0.0-9 wt % at least one physical blowing agent, where wt % is based on the total weight of all components of the composition.

[0030] In one embodiment, or in combination with any of the embodiments mentioned herein, the cellulose acetate has an acetyl degree of substitution (DS Ac )

[0031] In one embodiment, or in combination with any of the embodiments described herein, the plasticizer comprises triacetin, triethyl citrate, or polyethylene glycol having an average weight average molecular weight of 300 to 1000 Da. In one class of this embodiment, the plasticizer comprises triacetin. In one class of this embodiment, the plasticizer comprises triethyl citrate. In one class of this embodiment, the plasticizer comprises polyethylene glycol having an average weight average molecular weight of 300 to 1000 Da. In a subclass of this class, the polyethylene glycol has an average weight average molecular weight of 300 to 500 Da. In a subclass of this class, the polyethylene glycol has an average weight average molecular weight of 400 Da.

[0032] In one embodiment, or in combination with any of the embodiments mentioned herein, the natural filler is a biodegradable particulate material derived from renewable organic sources. Examples of natural fillers include, but are not limited to, pecan shell flour, walnut shell flour, wood flour, corn cob flour, rice husk flour, oat fiber flour, or combinations thereof.

[0033] In one embodiment, or in combination with any of the embodiments mentioned herein, the foamable composition further comprises an inorganic physical nucleating agent.

[0034] In one embodiment, or in combination with any of the embodiments mentioned herein, the foamable composition further does not include an inorganic physical nucleating agent.

[0035] In one embodiment, or in combination with any of the embodiments mentioned herein, the composition comprises ((C 1-3 ) alkyl)2O, CO2, N2, ((C 1-3 ) alkyl) CO, (C 1-6 ) alkanols, (C 4-6 In one class of this embodiment, the second physical blowing agent is selected from ((C 1-3)alkyl)O. In one class of this embodiment, the second physical blowing agent is CO. In one class of this embodiment, the second physical blowing agent is N. In one class of this embodiment, the second physical blowing agent is ((C 1-3 )alkyl)CO. In one class of this embodiment, the second physical blowing agent is (C 1-6 In one class of this embodiment, the second physical blowing agent is a (C) alkanol. 4-6 ) alkene.

[0036] In one embodiment, or in combination with any of the embodiments mentioned herein, the second physical blowing agent is present at 0.2-3 wt%, or 0.2-2.5 wt%, or 0.2-2 wt%, or 0.2-1.5 wt%, or 0.2-1 wt%, or 0.2-0.5 wt%, or 0.5-3 wt%, or 0.5-2.5 wt%, or 0.5-2 wt%, or 0.5-1.5 wt%, or 0.5-1 wt%, or 1-3 wt%, or 1-2.5 wt%, or 1-2 wt%, or 1-1.5 wt%, or 1.5-3 wt%, or 1.5-2.5 wt%, or 1.5-2 wt%, or 2-3 wt%.

[0037] In one embodiment, or in combination with any of the embodiments described herein, the plasticizer comprises triacetin, triethyl citrate, or polyethylene glycol having an average weight average molecular weight of 300 to 1000 Da. In one class of this embodiment, the plasticizer comprises triacetin. In one class of this embodiment, the plasticizer comprises triethyl citrate. In one class of this embodiment, the plasticizer comprises polyethylene glycol having an average weight average molecular weight of 300 to 1000 Da. In a subclass of this class, the polyethylene glycol has an average weight average molecular weight of 300 to 500 Da. In a subclass of this class, the polyethylene glycol has an average weight average molecular weight of 400 Da.

[0038] In one embodiment, or in combination with any of the embodiments described herein, the inorganic physical nucleating agent comprises a particulate composition having a median particle size of less than 2 microns. In a class of this embodiment, the physical nucleating agent comprises a particulate composition having a median particle size of 0.1 to 2 microns. In a class of this embodiment, the physical nucleating agent comprises a particulate composition having a median particle size of 0.5 to 2 microns. In a class of this embodiment, the physical nucleating agent comprises a particulate composition having a median particle size of 1 to 2 microns.

[0039] In one embodiment, or in combination with any of the embodiments mentioned herein, the inorganic physical nucleating agent comprises magnesium silicate, silicon dioxide, magnesium oxide, or combinations thereof.

[0040] In one embodiment, or in combination with any of the embodiments described herein, the organic physical nucleating agent comprises a biodegradable particulate natural filler having a maximum particle size of 600 microns or less. In a class of this embodiment, the organic physical nucleating agent comprises a biodegradable particulate natural filler having a maximum particle size of 250 microns or less. In a class of this embodiment, the organic physical nucleating agent comprises a biodegradable particulate natural filler having a maximum particle size of 180 microns or less. In a class of this embodiment, the organic physical nucleating agent comprises a biodegradable particulate natural filler having a maximum particle size of 150 microns or less. In a class of this embodiment, the organic physical nucleating agent comprises a biodegradable particulate natural filler having a maximum particle size of 75 microns or less. In a class of this embodiment, the organic physical nucleating agent comprises a biodegradable particulate natural filler having a maximum particle size of 60 microns or less.

[0041] In one embodiment, or in combination with any of the embodiments mentioned herein, the organic physical nucleating agent comprises a biodegradable particulate natural filler. Examples of biodegradable particulate natural fillers include, but are not limited to, pecan shell flour, walnut shell flour, wood flour, corn cob flour, rice husk flour, oat fiber flour, or combinations thereof.

[0042] In one embodiment, or in combination with any of the embodiments mentioned herein, the foam, composition, or foamable composition comprises two or more cellulose acetates having different degrees of acetyl substitution.

[0043] In one embodiment, or in combination with any of the embodiments mentioned herein, the first physical blowing agent is present in an amount of 1.3 to 1.5 wt%, or 1.3 to 2.0 wt%, or 1.3 to 2.5 wt%, or 1.3 to 3.0 wt%, or 1.3 to 3.5 wt%, or 1.3 to 4.0 wt%, or 1.3 to 4.5 wt%, or 1.3 to 5.0 wt%, or is 1.3 to 5.5 wt%, or 1.5 to 3.0 wt%, or 1.5 to 4.0 wt%, or 1.5 to 5.0 wt%, or 1.5 to 6.0 wt%, or 2.0 to 3.0 wt%, or 2.0 to 4.0 wt%, or 2.0 to 5.0 wt%, or 2.0 to 6.0 wt%, or 2.5 to 3.0 wt%, or 2.5 to 4.0 wt%, or 2.5 to 5 0.0wt%, or 2.5 to 6.0wt%, or 3.0 to 4.0wt%, or 3.0 to 5.0wt%, or 3.0 to 6.0wt%, or 0.0 to 9.0wt%, or 0.5 to 9.0wt%, or 1.0 to 9.0wt%, or 1.5 to 9.0wt%, or 2.0 to 9.0wt%, or 2.5 to 9.0wt%, or 3.0 to 9.0wt% , or 3.5-9.0 wt%, or 4.0-9.0 wt%, or 4.5-9.0 wt%, or 5.0-9.0 wt%, or 5.5-9.0 wt%, or 6.0-9.0 wt%, or 6.5-9.0 wt%, or 7.0-9.0 wt%, or 7.5-9.0 wt%, or 8.0-9.0 wt%, or 8.5-9.0 wt%.

[0044] In one embodiment, or in combination with any of the embodiments mentioned herein, the physical nucleating agent is present in an amount of 0.1 to 2.5 wt%, or 0.1 to 2.0 wt%, or 0.1 to 1.5 wt%, or 0.1 to 1.0 wt%, or 0.1 to 0.5 wt%, or 0.1 to 5.0 wt%, or 0.1 to 10.0 wt%, or 0.1 to 20.0 wt%, or 0.1 to 30.0 wt%, or 0.1 to 40.0 wt%, or 0.2 to 3.0 wt%, or 0.2 to 2.5 wt%, or 0.2 to 2.0 wt%, or 0.2 to 1.5 wt%, or 0.2 to 1.0 wt%. t%, or 0.2 to 0.5 wt%, or 0.5 to 2.5 wt%, or 0.5 to 2.0 wt%, or 0.5 to 1.5 wt%, or 0.5 to 1.0 wt%, or 1.0 to 6.0 wt%, or 1.0 to 5.5 wt%, or 1.0 to 5.0 wt%, 1.0 to 4.5 wt%, or 1.0 to 4.0 wt%, or 1.0 to 3.5 wt%, or 1.0 to 3.0 wt%, or 1.0 to 2.5 wt%, or 1.0 to 2.0 wt%, or 1.0 to 1.5 wt%, or 1.5 to 6.0 wt%, or 1.5 to 5.5 wt%, or 1.5 to 5.0 wt%, or or 1.5 to 4.5 wt%, or 1.5 to 4.0 wt%, or 1.5 to 3.5 wt%, or 1.5 to 3.0 wt%, or 1.5 to 2.5 wt%, or 1.5 to 2.0 wt%, or 2.0 to 6.0 wt%, or 2.0 to 5.5 wt%, or 2.0 to 5.0 wt%, or 2.0 to 4.5 wt%, or 2.0 to 4.0 wt%, or 2.0 to 3.5 wt%, or 2.0 to 3.0 wt%, or 2.0 to 2.5 wt%, or 2.5 to 6.0 wt%, or 2.5 to 5.5 wt%, or 2.5 to 5.0 wt%, or 2.5 to 4.5 wt% , or 2.5 to 4.0 wt%, or 2.5 to 3.5 wt%, or 2.5 to 3.0 wt%, or 3.0 to 6.0 wt%, or 3.0 to 5.5 wt%, or 3.0 to 5.0 wt%, or 3.0 to 4.5 wt%, or 3.0 to 4.0 wt%, or 3.0 to 3.5 wt%, or 3.5 wt% to 6.0 wt%, or 3.5 to 5.5 wt%, or 3.5 to 5.0 wt%, or 3.5 to 4.5 wt%, or 3.5 to 4.0 wt%, or 4.0 to 6.0 wt%, or 4.0 to 5.5 wt%, or 4.0 to 5.0 wt%, or 4.0 to 4.5 wt%, or 4.5-6.0 wt%, or 4.5-5.5 wt%, or 4.5-5.0 wt%.

[0045] In one embodiment, or in combination with any of the embodiments mentioned herein, the plasticizer is present in an amount of 5 to 30 wt%, or 5 to 25 wt%, or 5 to 20 wt%, or 5 to 15 wt%, or 5 to 10 wt%, or 6 to 30 wt%, or 6 to 25 wt%, or 6 to 20 wt%, or 6 to 15 wt%, or 6 to 10 wt%, or 7 to 30 wt%, or 7 to 25 wt%, or 7 to 20 wt%, or 7 to 15 wt%, or 7 to 10 wt%, or 8 to 30 wt%, or 8 to 25 wt%, or 8 to 25 wt%. %. Present at 20 wt%, or 8-15 wt%, or 8-10 wt%, or 9-30 wt%, or 9-25 wt%, or 9-20 wt%, or 8-15 wt%, or 9-30 wt%, or 9-25 wt%, or 9-20 wt%, or 9-15 wt%, or 10-30 wt%, or 10-25 wt%, or 10-20 wt%, or 10-15 wt%, or 15-30 wt%, or 15-25 wt%, or 15-20 wt%, or 20-30 wt%, or 20-25 wt%.

[0046] In one embodiment, or in combination with any of the embodiments mentioned herein, the foamable composition may be in the form of pellets or a powder.

[0047] The present application discloses articles made from any of the above-described biodegradable cellulose acetate foams or compositions disclosed herein.

[0048] To be considered "depositable," a material must meet four criteria: (1) the material must pass biodegradation requirements when tested under controlled deposition conditions at elevated temperature (58°C) according to ISO 14855-1 (2012), corresponding to an absolute 90% biodegradation or a relative 90% biodegradation to a control polymer; (2) the material must reach 90% disintegration when tested under aerobic deposition conditions according to ISO 16929 (2013); (3) the tested material must meet all requirements for volatile solids, heavy metals, and fluorine as specified by ASTM D6400 (2012), EN 13432 (2000), and ISO 17088 (2012); and (4) the material must not adversely affect plant growth. As used herein, the term "biodegradable" generally refers to the biological transformation and consumption of organic molecules. Biodegradability is an inherent property of the material itself, and materials may exhibit varying degrees of biodegradability depending on the specific conditions to which they are exposed. The term "degradability" refers to the tendency of a material to physically break down into smaller pieces when exposed to specific conditions. Disintegration depends on both the material itself and the physical size and composition of the item being tested. Ecotoxicity measures the effect of a material on plants, and the heavy metal content of a material is determined according to procedures set forth in standard test methods.

[0049] To be considered "biodegradable," a material must exhibit at least 90 percent total biodegradation under home composting conditions (e.g., compared to the initial sample), or at least 90 percent of the maximum degradation of an appropriate reference material after a plateau has been reached for both the reference and test items, according to French standard NF T 51-800 and Australian standard AS 5810. The maximum test period for biodegradation under home composting conditions is one year.

[0050] To be considered "biodegradable" under industrial deposition conditions according to ASTM D6400 and ISO 17088, at least 90% of the organic carbon in the whole article (or in each component present in an amount greater than 1% by dry mass) must be converted to carbon dioxide by the end of the test period, when compared to a control or absolute value. According to European Standard ED 13432 (2000), materials must demonstrate a total biodegradation of at least 90 percent, or at least 90 percent of the maximum degradation of an appropriate reference material after reaching a plateau for both the reference and test items. The maximum test period for biodegradability under industrial deposition conditions is 180 days.

[0051] To be considered "biodegradable" under soil deposition conditions according to Vincotte's OK Biodegradable Soil Compliance Mark and DIN CERTCO's DIN Geprruft Biodegradable Soil Certification Scheme, a material must demonstrate a total biodegradation of at least 90% (e.g., compared to the initial sample) or at least 90 percent of the maximum degradation of an appropriate reference substance after reaching a plateau for both the reference and test items. The maximum test period for biodegradability under soil deposition conditions is 2 years.

[0052] In one embodiment, or in combination with any of the embodiments described herein, the biodegradable cellulose acetate foam or article is industrially depositable or domestically depositable. In a subclass of this class, the foam or article is industrially depositable. In a subclass of this subclass, the foam or article has a thickness of less than 6 mm. In a subclass of this subclass, the foam or article has a thickness of less than 3 mm. In a subclass of this subclass, the article has a thickness of less than 1.1 mm. In a subclass of this class, the foam or article is domestically depositable. In a subclass of this subclass, the foam or article has a thickness of less than 6 mm. In a subclass of this subclass, the foam or article has a thickness of less than 3 mm. In a subclass of this subclass, the foam or article has a thickness of less than 1.1 mm. In a subclass of this subclass, the foam or article has a thickness of less than 0.8 mm. In a subclass of this subclass, the foam or article has a thickness of less than 0.6 mm. In a subclass of this subclass, the foam or article has a thickness of less than 0.4 mm.

[0053] In one embodiment, or in combination with any of the embodiments mentioned herein, the thickness of the foam or article is less than 3 mm.

[0054] In one embodiment, or in combination with any of the embodiments mentioned herein, the foam or article exhibits greater than 90% disintegration after 12 weeks according to the film disintegration test protocol, as described herein.

[0055] The compositions used to produce biodegradable cellulose acetate foams may contain other additives, such as fillers, stabilizers, odor control agents, waxes, compatibilizers, biodegradation accelerators, dyes, pigments, colorants, lubricants, antioxidants, viscosity modifiers, antifungal agents, heat stabilizers, antibacterial agents, softeners, mold release agents, and combinations thereof. It should be noted that the same type of compound or material may be identified or included for multiple categories of components in a cellulose acetate composition. For example, polyethylene glycol (PEG) may function as a plasticizer or as an additive that does not function as a plasticizer, such as a hydrophilic polymer or biodegradation accelerator; e.g., low molecular weight PEG has a plasticizing effect, while high molecular weight PEG functions as a hydrophilic polymer but does not have a plasticizing effect.

[0056] In one embodiment, or in combination with any other embodiment mentioned herein, the foam, composition, or foamable composition further comprises a photodegradation catalyst. In a class of this embodiment, the photodegradation catalyst is titanium dioxide or iron oxide. In a subclass of this class, the photodegradation catalyst is titanium dioxide. In a subclass of this class, the photodegradation catalyst is iron oxide.

[0057] In one embodiment, or in combination with any other embodiment mentioned herein, the foam, composition, or foamable composition further comprises a pigment. In a class of this embodiment, the pigment is titanium dioxide, carbon black, or iron oxide. In a subclass of this class, the pigment is titanium dioxide. In a subclass of this class, the pigment is carbon black. In a subclass of this class, the pigment is iron oxide. In a subclass of this class, the pigment is a biodegradable particulate natural filler.

[0058] Claims not limited to the disclosed embodiments The above-described preferred embodiments of the present invention are merely used as an illustration and should not be used to limit the scope of the present invention. Modifications to the above-described exemplary embodiments can be easily made by those skilled in the art without departing from the spirit of the present invention.

[0059] The inventors state herein that they intend to rely on the doctrine of equivalents to determine and assess the reasonable equitable scope of the invention as it relates to any device that departs, but does not depart in substance, from the literal scope of the invention as set forth in the following claims.

[0060] In one embodiment, or in combination with any other embodiment, the foam or article exhibits greater than 30% disintegration after 12 weeks according to the disintegration test protocol as described herein or its surrogates in accordance with ISO 16929 (2013). In one embodiment, or in combination with any of the embodiments mentioned herein, the foam or article exhibits greater than 50% disintegration after 12 weeks according to the film disintegration test protocol as described herein. In one embodiment, or in combination with any of the embodiments mentioned herein, the foam or article exhibits greater than 70% disintegration after 12 weeks according to the film disintegration test protocol as described herein. In one embodiment, or in combination with any other embodiment, the foam or article exhibits greater than 80% disintegration after 12 weeks according to the disintegration test protocol as described herein or its surrogates in accordance with ISO 16929 (2013). In one embodiment, or in combination with any of the embodiments mentioned herein, the foam or article exhibits greater than 90% disintegration after 12 weeks according to the film disintegration test protocol as described herein. In one embodiment, or in combination with any of the embodiments mentioned herein, the foam or article exhibits greater than 95% disintegration after 12 weeks according to the film disintegration test protocol, as described herein.

[0061] Example For the examples herein, the test methods, abbreviations, and materials are as follows:

[0062] Colors were measured using a chromameter (Konica Minolta CR-400) in the CIE color space L * a * b * The values ​​are reported. * where 0 = black and 100 = white; * In , negative values ​​indicate greenness and positive values ​​indicate redness;b * In the chromatogram, negative values ​​indicate blueness and positive values ​​indicate yellowness. To measure the color of film samples, 10 mil film was placed on a white cardboard background. To measure the color of filler samples, an amount of filler that was not visible through the microscope slide was placed between the microscope slide and a cover slide.

[0063] Particle sizes are reported in microns as the upper particle size limit (not to exceed) based on standard US mesh sizes.

[0064] Film thickness was determined by the thickness of the frame used to compression mold the film samples. The frame thickness used was either 254 microns (10 mils) or 508 microns (20 mils).

[0065] Tensile properties are measured according to ASTM-D638 on an Instron tensile test frame. Stress at break and Young's modulus are reported in MPa, strain at break is reported in %, and energy at break is reported in N / mm 2 It is reported in.

[0066] Density is measured by the water displacement method, where the mass (g) of an approximately 1 cm x 3 cm foam sample is recorded before immersing the sample in water and recording the volume of water displaced (cm). Density is calculated by dividing the mass by the volume.

[0067] Cell size is determined using a scanning electron microscope by capturing cross-sectional images of the foam sample prepared via a microtome at 1000x magnification at a 90° angle relative to the surface of the sample. Then, using digital image analysis software (ImageJ), the diameter of at least 10 randomly selected cells is measured. The average diameter is recorded as the cell size of the sample.

[0068] Weight percent, sometimes abbreviated as wt%, is based on the weight of all other ingredients (both solid and liquid) in the formulation unless otherwise indicated.

[0069] Cellulose acetate (CA) CA1: CA-398-30 (39.7 wt% acetyl); commercially available from Eastman Chemical Company CA2: Cellulose acetate FE700 (40 wt% acetyl); commercially available from Eastman Chemical Company Liquid Plasticizer TEC - Triethyl citrate 98% - CAS No. 77-93-0; MW: 276.28; commercially available from Sigma Aldrich, product number 27500 TA - Triacetin - commercially available from Eastman Chemical Company Natural Fillers NF1 - Pecan shell flour - particle size: ≦74 μm (200 mesh); commercially available from Composition Materials Co., Inc. NF2 - Walnut shell powder - particle size: ≦149 μm (100 mesh); commercially available from Composition Materials Co., Inc. NF3 - Wood Flour 30 / 60 - Particle size: 50% ≦ 600 μm (30 mesh) and 50% ≦ 250 μm (60 mesh); commercially available from Composition Materials Co., Inc. NF4-Wood Flour 60 - Particle size: ≦250 μm (60 mesh); commercially available from Composition Materials Co., Inc. NF5 - Corncob biofiller - particle size: ≤177 μm (80 mesh); commercially available from Composition Materials Co, Inc. NF5 - Rice husk biofiller - particle size: ≤177 μm (80 mesh); commercially available from Composition Materials Co., Inc. NF7 - Oat fiber powder - particle size: ≦57 μm, commercially available from Nunatural NF8 - Hemp fiber - Fiber length: Maximum 6mm Inorganic Physical Nucleating Agents (IPNA) Talc - Talc ABT 1000; commercially available from Specialty Minerals

[0070] CA Film / Foam Preform Melt Processing Protocol Composite pellets were formed from CA powder, liquid plasticizer, natural filler, and optional inorganic physical nucleating agent. The dry ingredients were bag-blended to a flowable powder, which was fed into an 18 mm (Leistritz) twin-screw extruder equipped with a single-hole die. The liquid plasticizer was fed into Zone 2 of the extruder through a 0.020-inch bore injector via a liquid injection unit fed by a Witte gear pump and controlled by a Hardy 4060 controller. The composite strand was passed through a water trough and pelletized in a ConAir pelletizer. The pellets were dried overnight under vacuum at 70°C in a vacuum oven with a vacuum of 7-10 psi.

[0071] The dried pellets were then converted into film samples using a compression molding machine (Pasadena Hydraulics Inc., PW-220-C-X1-4) and molding frames with thicknesses of either 254 microns (10 mils) or 508 microns (20 mils). The samples were molded at 400°F (204.4°C) for 90 seconds with a ram force of 8,000 to 10,000 pounds. Pressure was then released and reapplied at 20,000 to 22,000 pounds for another 30 seconds. Pressure was then released and reapplied at 20,000 to 22,000 pounds for a final 60 seconds.

[0072] Foaming Protocol Batch foaming of film samples was performed in a 300 mL high-pressure autoclave (Parr Instrument Company model number 4561) with a diameter of 2.5 inches and a depth of 4 inches. The autoclave was equipped with a thermocouple and pressure sensor. The dip tube, agitator shaft, and impeller were removed. 1 inch x 1 inch CA film samples (film thickness was either 10 or 20 mils as shown in Table 1) were placed in a 1.5 inch x 1.5 inch x 0.5 inch (L x W x H) folded-tray tray. Trays containing film samples were stacked alternately in three or four layers within the autoclave, which was then closed, sealed, and heated to the desired temperature within the range of 150°C to 230°C. Once the autoclave reached the desired temperature, the vessel was opened. CO2 The autoclave was pressurized with gas to the desired pressure within the range of 50 bar to 130 bar, and the autoclave was stabilized at the target temperature and pressure. After stabilization, the CA film sample was held at the target temperature and target pressure for 30 minutes. CO2 The gas was allowed to permeate into the film. After 30 minutes at the target temperature and pressure, the 1 / 4 inch vent valve was opened and the autoclave was purged with nitrogen gas. The rapid pressure release caused the film sample to expand into a foam. After the autoclave was cooled to room temperature, the foam sample was removed and its density (g / cm 3 ) and cell size (nm) were analyzed.

[0073] [Table 1-1]

[0074] [Table 1-2]

[0075] Example 1 - Fillers as natural colorants Samples of natural fillers were evaluated for color. The natural fillers evaluated included pecan shell flour (NF1); walnut shell flour (NF2); wood flour 30 / 60 (NF3); wood flour 60 (NF4); corn cob flour (NF5); rice husk flour (NF6); and oat fiber powder (NF7). Following the melt processing protocol described above, film samples 508 microns thick were produced according to the formulations listed in Table 1, Samples 1-8. The resulting films were analyzed for color. Table 2 shows the L measured by a Chromameter. * , a * , and b * Summarize the values ​​of

[0076] [Table 2]

[0077] As can be seen in Table 2, all filler and film samples exhibited a positive a * value, and a positive b indicates a yellow hue * For most films, a * and b * The higher the L value, the more intense the color. After melt processing, film samples generally exhibited a lower L value, which indicated a darker color than the filler exhibited before melt processing. * The film of sample 4 (NF3) appeared darker (L * low), a * and b *Although the σ values ​​were not high, significant filler aggregation was observed, resulting in a mottled appearance with large areas of light and dark color, which likely contributed to the incompatible color results for this sample. Samples 1-8 demonstrate that incorporating natural fillers into CA films is an effective means for producing CA films and foam / foam articles with natural colors that cannot be achieved with common commercially available compositions utilizing polystyrene, plasticizers, and talc. The natural appearance of the foam products in Samples 2-8 is a result of the use of natural fillers and is desirable because they are easily distinguishable from articles made from non-biodegradable white polystyrene-based Styrofoam.

[0078] Example 2 - Tensile properties of CA films containing natural fillers The pellets were compounded and compression molded into film samples according to the melt processing protocol described above and the formulations listed in Table 1, Samples 9-16. The resulting 508 micron thick films were conditioned at 25°C and 50% RH for 48 hours and then tested for tensile properties according to ASTM-D638.

[0079] [Table 3]

[0080] The stress at break and Young's modulus tended to decrease as the maximum particle size of the natural filler increased, while the strain at break and energy at break did not appear to be affected by particle size. Comparing the fine particle fillers (samples 9-15) with the hemp fiber filler (sample 16), the films with the fine particle natural filler were found to be more ductile and had higher strain at break and energy at break.

[0081] Example 3 - Batch Foaming of CA Film with Natural Fillers and Talc The pellets were compounded and compression molded into a 254 micron thick film according to the melt processing protocol described above and the formulations listed in Table 1, Samples 17-24. Batch foaming of film samples was carried out according to the foaming protocol described above using a pressure of 130 bar and a temperature of 200° C. The density and cell size of the foam samples were measured and the resulting densities and cell sizes are summarized in Table 4 below.

[0082] [Table 4]

[0083] These results demonstrate that cellulose acetate compositions containing various types of natural fillers and talc can be converted into cellulose acetate foam samples that exhibit densities and cell sizes useful in many low-density foam product applications.

[0084] Example 4 - Talc-Free Foam Formulation with High Natural Filler Content Films containing various types of natural fillers and no inorganic physical nucleating agent were produced according to the melt processing protocol described above and the formulations listed in Table 1, Samples 25-39. The resulting film samples were foamed according to the foaming protocol at the pressures and temperatures listed in Table 1. None of the samples contained an inorganic physical nucleating agent. The density and cell size of the foam samples were measured, and the resulting densities and cell sizes are summarized in Table 5 below.

[0085] [Table 5]

[0086] Natural fillers not only modify the appearance of the cellulose acetate composition and the resulting foam, but also act as physical nucleators, negating the need for inorganic physical nucleators such as talc. Furthermore, low density foams can be produced with high loadings of natural fillers, lowering the overall raw material costs of the composition. For example, 3 Acceptable low density foams of less than 1000 MPa can be achieved at loadings with up to 30% oat fiber flour or wood flour without utilizing any inorganic physical nucleating agents.

[0087] Example 5 - Natural Fillers to Reduce Foam Density of CA Natural fillers are hygroscopic and can be used as carriers for water, which acts as a physical blowing agent during foaming, reducing foam density.

[0088] To evaluate the equilibrium moisture absorption of the natural fillers, samples of each natural filler material were dried overnight under vacuum. After drying, the samples were weighed, and the % weight loss was considered the equilibrium moisture absorption of the material. Each dried natural filler sample was then placed in an individual small vial, which was then placed in a larger jar containing water. The large jars were then sealed and conditioned overnight in an oven at either 25°C or 70°C. The conditioned natural filler samples were reweighed, and their moisture absorption values ​​are shown in Table 6 below.

[0089] [Table 6]

[0090] Samples conditioned at ambient temperature (25°C) returned to a moisture content similar to the initially measured equilibrium moisture absorption, however, samples conditioned at elevated temperature (70°C) absorbed significantly more moisture.

[0091] To evaluate the effect of high-water-content fillers, CA film samples containing 10% NF7 were prepared according to the melt processing protocol described above and the formulations listed in Table 1, Samples 40-41. Batch foaming of the film samples was performed according to the foaming protocol. Sample 40, the dry CA film, was not conditioned prior to foaming. Meanwhile, Sample 41, the wet CA film, was placed in a small jar and then placed in a larger jar containing water. The larger jar was then sealed and conditioned overnight at 70°C prior to foaming.

[0092] [Table 7]

[0093] Table 7 demonstrates that preconditioning CA films containing hygroscopic natural fillers in humid environments allows for lower density foams with larger cell sizes. As the natural fillers absorb moisture during conditioning, the water content of the film increases, and the absorbed moisture then acts as a physical blowing agent to reduce the density of the foam.

[0094] Example 6 - Natural fillers as alternative nucleating agents (replacing talc) Films containing various types of natural fillers were produced according to the melt processing protocol described above and the formulations listed in Table 1, Samples 42-66. The film samples were then batch foamed according to the foaming protocol and Table 1. The resulting foam samples were evaluated for density and cell size.

[0095] The talc-free formulations of this example demonstrate that natural fillers can also effectively function as nucleating agents. At loadings as low as 3%, several natural fillers exhibited sufficient nucleation and foaming, resulting in low cell densities and fine cell morphologies. Foaming pressures of 100 bar and 130 bar were found to be optimal conditions for producing low-density foams without inorganic nucleating agents.

[0096] Additionally, natural fillers can be used in combination with talc to further reduce foam density, increase average cell size, and reduce the raw material costs of the composition. At low foaming pressures (50 and 70 bar), the addition of 1 wt% talc increased foam density for most samples but decreased cell size. Surprisingly, at high foaming pressures (100 and 130 bar), the addition of 1 wt% talc substantially decreased foam density while increasing cell size.

[0097] [Table 8]

Claims

1. 1. A foamable composition comprising: 30 to 92 wt % of cellulose acetate; 5-30 wt % of at least one plasticizer; 3-40 wt % of at least one natural filler; 0-9 wt % of at least one physical blowing agent; A foamable composition wherein wt % is based on the total weight of the composition.

2. 10. The foamable composition of claim 1, wherein the cellulose acetate has an average degree of acetyl substitution in the range of 2.2 to 2.

6.

3. The foamable composition of any one of claims 1 to 2, wherein the at least one plasticizer is selected from the group consisting of triacetin, triethyl citrate, or polyethylene glycol.

4. A foamable composition according to any one of claims 1 to 3, wherein the natural filler is a biodegradable particulate material derived from renewable organic sources.

5. 5. The foamable composition of claim 4, wherein the natural filler is selected from the group consisting of pecan shell flour, walnut shell flour, wood flour, corn cob flour, rice husk flour, oat fiber flour, or combinations thereof.

6. The foamable composition of any one of claims 1 to 5, further comprising an inorganic physical nucleating agent.

7. The foamable composition of any one of claims 1 to 5, which is free of inorganic physical nucleating agents.

8. A foamable composition according to any one of claims 1 to 7, wherein the natural filler has a maximum particle size of from 50 to 600 microns.

9. 9. The foamable composition of any one of claims 1 to 8, wherein the natural filler further comprises up to 22 wt% water, based on the dry weight of the natural filler.

10. 10. The foamable composition of any one of claims 1 to 9, further comprising a chemical foam composition comprising: (a) a blowing agent; and (b) a carrier polymer having a melting point of 180°C or less.

11. 11. The foamable composition of claim 10, wherein the foaming agent comprises sodium bicarbonate, sodium carbonate, citric acid, or a combination thereof.

12. The foamable composition of any one of claims 10 to 11, wherein the carrier polymer is a biodegradable polymer.

13. 13. The foamable composition of claim 12, wherein the carrier polymer comprises polybutylene succinate ("PBS"), polycaprolactone ("PCL"), polylactic acid ("PLA"), polyhydroxyalkanoate ("PHA"), polybutylene adipate terephthalate ("PBAT"), a starch derivative, poly(butylene succinate-cobutylene adipate) ("PBSA"), or a combination thereof.

14. 14. The foamable composition of any one of claims 12 to 13, wherein the carrier polymer is present at 25 to 75 wt%, based on the total weight of the chemical foam composition.

15. The foamable composition of any one of claims 1 to 14, in the form of a powder or pellets.

16. A foam formed from the foamable composition of any one of claims 1 to 15, which is biodegradable, industrially depositable, or domestically depositable.

17. The foam has a viscosity of 0.60 g / cm ３ or less, or 0.50 g / cm ３ or less, or 0.40 g / cm ３ or less, or 0.38 g / cm ３ , or 0.36 g / cm ３ or less, or 0.34 g / cm ３ or less, or 0.32 g / cm ３ or less, or 0.30 g / cm ３ 17. The foam of claim 16 having a density:

18. 18. The foam of any one of claims 16 to 17, wherein the foam has an average cell size of at least 40 μm, or at least 50 μm, or at least 60 μm, or at least 70 μm, or at least 80 μm, or at least 90 μm, or at least 100 μm, or at least 110 μm, or at least 120 μm, or at least 130 μm, or at least 140 μm, or at least 150 μm, or at least 160 μm, or at least 180 μm, or at least 200 μm, or at least 250 μm, or at least 300 μm, or at least 350 μm, or at least 400 μm, or at least 450 μm, or at least 500 μm, or at least 550 μm, or at least 600 μm.

19. The foam according to any one of claims 16 to 19, wherein the foam does not contain any inorganic fine particle component.

20. The foam of any one of claims 16 to 19, wherein the article is a thermoformed foam article or a molded foam article.

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