WO2023220007A1 - Mousse durable - Google Patents

Mousse durable Download PDF

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Publication number
WO2023220007A1
WO2023220007A1 PCT/US2023/021459 US2023021459W WO2023220007A1 WO 2023220007 A1 WO2023220007 A1 WO 2023220007A1 US 2023021459 W US2023021459 W US 2023021459W WO 2023220007 A1 WO2023220007 A1 WO 2023220007A1
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WO
WIPO (PCT)
Prior art keywords
foam
chemical foaming
foaming agent
cellulose acetate
astm
Prior art date
Application number
PCT/US2023/021459
Other languages
English (en)
Inventor
Drew V. Speer
Jingran YI
Eric ELLENBOGEN
Parimal Vadhar
Original Assignee
Cryovac, Llc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
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Publication date
Application filed by Cryovac, Llc filed Critical Cryovac, Llc
Publication of WO2023220007A1 publication Critical patent/WO2023220007A1/fr

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    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J9/00—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof
    • C08J9/04—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof using blowing gases generated by a previously added blowing agent
    • C08J9/06—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof using blowing gases generated by a previously added blowing agent by a chemical blowing agent
    • C08J9/08—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof using blowing gases generated by a previously added blowing agent by a chemical blowing agent developing carbon dioxide
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J9/00—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof
    • C08J9/04—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof using blowing gases generated by a previously added blowing agent
    • C08J9/12—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof using blowing gases generated by a previously added blowing agent by a physical blowing agent
    • C08J9/122—Hydrogen, oxygen, CO2, nitrogen or noble gases
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J9/00—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof
    • C08J9/04—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof using blowing gases generated by a previously added blowing agent
    • C08J9/12—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof using blowing gases generated by a previously added blowing agent by a physical blowing agent
    • C08J9/14—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof using blowing gases generated by a previously added blowing agent by a physical blowing agent organic
    • C08J9/141—Hydrocarbons
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J9/00—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof
    • C08J9/04—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof using blowing gases generated by a previously added blowing agent
    • C08J9/12—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof using blowing gases generated by a previously added blowing agent by a physical blowing agent
    • C08J9/14—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof using blowing gases generated by a previously added blowing agent by a physical blowing agent organic
    • C08J9/142—Compounds containing oxygen but no halogen atom
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J2203/00—Foams characterized by the expanding agent
    • C08J2203/02—CO2-releasing, e.g. NaHCO3 and citric acid
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J2203/00—Foams characterized by the expanding agent
    • C08J2203/08—Supercritical fluid
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J2203/00—Foams characterized by the expanding agent
    • C08J2203/12—Organic compounds only containing carbon, hydrogen and oxygen atoms, e.g. ketone or alcohol
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J2203/00—Foams characterized by the expanding agent
    • C08J2203/14—Saturated hydrocarbons, e.g. butane; Unspecified hydrocarbons
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J2203/00—Foams characterized by the expanding agent
    • C08J2203/18—Binary blends of expanding agents
    • C08J2203/184—Binary blends of expanding agents of chemical foaming agent and physical blowing agent, e.g. azodicarbonamide and fluorocarbon
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J2203/00—Foams characterized by the expanding agent
    • C08J2203/20—Ternary blends of expanding agents
    • C08J2203/204—Ternary blends of expanding agents of chemical foaming agent and physical blowing agents
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J2205/00—Foams characterised by their properties
    • C08J2205/04—Foams characterised by their properties characterised by the foam pores
    • C08J2205/044—Micropores, i.e. average diameter being between 0,1 micrometer and 0,1 millimeter
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J2301/00—Characterised by the use of cellulose, modified cellulose or cellulose derivatives
    • C08J2301/08—Cellulose derivatives
    • C08J2301/10—Esters of organic acids
    • C08J2301/12—Cellulose acetate

Definitions

  • the subject matter disclosed herein relates to sustainable foams. More particularly, the subject matter relates to low density foams having a small cell size in which the foam includes a cellulose acetate.
  • Certain grades of cellulose acetate are known to be biodegradable and compostable.
  • nucleating agents are used in combination with physical blowing agents.
  • foams including certain nucleating agents, such as inert inorganic nucleating agent result in foams having higher densities, larger cell sizes or both.
  • the presence of inert inorganic nucleating agent can be detrimental to being able to recycle or reuse foams.
  • a sustainable foam having 72-84 wt% cellulose acetate, 10-25 wt% plasticizer and 0.04-3 wt% of a chemical foaming agent.
  • the foam having a density of less than any of 0 10, 0.08 or 0.06 g/cc as measured in accordance with ASTM DL505.
  • the foam having an average cell size of less than any of the following 300, 250, 200, 150, 120, 100, or 80 microns in accordance with ASTM D-3756.
  • a foam in one exemplary embodiment, comprises 72-84 wt% cellulose acetate, 10-25 wt% plasticizer and 0.04-3 wt% of a chemical foaming agent.
  • the foam having a density of less than any of 0.10, 0.08 or 0.06 g/cc as measured in accordance with ASTM DI 505.
  • the foam having an average cell size of less than any of the following 300, 250, 200, 150, 120, 100, or 80 microns in accordance with ASTM D-3756.
  • a method of making a foam comprises the steps of mixing a blend of 72-84 wt% cellulose acetate, 15-25 wt% of a plasticizer and 0.04-3 wt% of a chemical foaming agent, all wt% based on the total weight of the mixed blend. Heating the blend. Introducing a physical blowing agent to the blend. Extruding the blend and physical blowing agent to form a foam.
  • the foam having a density of less than any of 0.10, 0.08 or 0.06 g/cc as measured in accordance with ASTM D1505.
  • the foam having an average cell size of less than any of the following 300, 250, 200, 150, 120, 100, or 80 microns in accordance with ASTM D-3756.
  • a foam packaging article comprises a comprises a foam formed into a three-dimensional packaging article and a product situated on the three-dimensional packaging article.
  • the foam comprises 72-84 wt% cellulose acetate, 10-25 wt% plasticizer and 0.04-3 wt% of a chemical foaming agent.
  • the foam having a density of less than any of 0.10, 0.08 or 0.06 g/cc as measured in accordance with ASTM DI 505.
  • the foam having an average cell size of less than any of the following 300, 250, 200, 150, 120, 100, or 80 microns in accordance with ASTM D-3756.
  • FIG. 1 is a block diagram showing an exemplary' process for making a foam according to embodiments
  • FIG. 2 is an image of foam 3 as described herein;
  • FIG. 3 is a block diagram showing an exemplary' process for making a foam according to embodiments.
  • FIG. 4 is a schematic cutaway view of an exemplary foam extruder according to embodiments herein.
  • biodegradable and compostable In the United States standards defining test standards for labeling a product “biodegradable and compostable,” are conducted under ASTM D6400. This standard establishes a standard of industrial compostability. However, industrial compostability is performed at temperatures higher than are typically achieved in at home composting. Thus, products that satisfy this standard may not properly break down if consumers put them in their home compost heaps.
  • biodegradable and compostable currently have different standard in some jurisdictions.
  • biodegradable generally refers to the biological conversion and consumption of organic molecules. Biodegradability is an intrinsic property of the material itself, and the material can exhibit different degrees of biodegradability, depending on the conditions (i.e. heat and pressure) to which the material is exposed.
  • EN 13432 requires that 90% of the product, by mass, is converted to CO2 within 6 months, and that after 3 months of composting and subsequent sifting through a 2 mm sieve no more than 10% residue, by mass, remains.
  • compostable means a material that satisfies both (1) ASTM D-6400 and (2) EN 13432, the contents of both are incorporated herein by reference.
  • Cellulose acetate is an acetate ester derivative of cellulose.
  • Cellulose can be obtained from many different sources such as, but not limited to wood pulp, cotton linters, plant fibers, and bacterial sources.
  • Cellulose acetate is generally considered to be a nontoxic, non-irritant, and biodegradable material.
  • a method of producing cellulose acetates is esterification of cellulose.
  • Cellulose is converted to a cellulose ester by mixing cellulose with acids, acid anhydrides, and catalysts. Hydrolysis process is then utilized to obtain cellulose acetates. The degree of esterification is expressed by acetyl value or as combined acetic acid.
  • Fully acetylated cellulose acetate (cellulose triacetate) contains 44.8 percent combined acetyl or 62.5 percent as combined acetic acid.
  • Cellulose triacetate is then hydrolyzed to give a cellulose acetate which contains approximately 39.4 percent combined acetyl or 55.0 percent combined acetic acid.
  • the cellulose acetate has an acetyl content is between 36-44%. Acetyl content is measured according to ASTM D-817. Suitable cellulose acetate compositions are commercially available as CA398-30 from Eastman and CA398-10 available from Eastman.
  • cellulose acetate can be prepared by converting cellulose to a cellulose ester with reactants that are obtained from recycled materials, e.g., a recycled plastic content utilizing a syngas source.
  • reactants can be cellulose reactants that include organic acids and/or acid anhydrides used in the esterification or acylation reactions of the cellulose.
  • the cellulose acetate is derived from a renewable source. For example, from wood or agriculture growth.
  • the cellulose acetate contains both recycled materials and is derived from a renewable source.
  • Cellulose acetate can have a major portion of biobased carbon content.
  • the cellulose acetate has a biobased content of at least any of 50%, 55%, 60% or 65% measured in accordance with ASTM D-6866.
  • the cellulose acetate includes at least 10 wt%, 20 wt%, 30 wt%, 40 wt% or 50 wt% of recycled cellulose acetate.
  • Recycled cellulose acetate may be recycled as part of a later processing scrap (such as skeleton recovery of thermoformed articles) or gathered from other sources.
  • the recycled cellulose acetate can be ground, dried and reused along with, or instead of virgin cellulose acetate.
  • the cellulose acetate composition can include additional additives.
  • Additional additives include carriers, fillers, plasticizers, stabilizers, waxes, compatibilizers, composability promoters, anti-oxidants, antifungal agents, colorants, anti-fogging agents, aging modifiers such as glycerol monostearate, anti-static, impact modifiers, antibacterial agents, flame retardants, processing aids, and combinations thereof.
  • Such additional additives can be blended with and formed with the cellulose acetate material (e.g. as flake or pellet), or can be added as a separate component prior to extrusion.
  • Plasticizers are used to improve processability of the cellulose acetate composition. Plasticizers can improve rheological, thermal, and mechanical properties. Plasticizer help the foam become thermoformable, reduces melt temperature (Tg of amorphous materials), or improves melt flow of the cellulose acetate.
  • the plasticizer may be formulated with the cellulose acetate or mixed into a blend prior to extrusion of the foam.
  • the resin mixture may include the plasticizer as part of the cellulose acetate composition, the plasticizer may be added the extruder as a separate component, or both such that the plasticizer is distributed throughout the resin mixture in the extruder.
  • the plasticizer is homogenously distributed throughout the resin mixture.
  • Exemplary plasticizers include esters of saturated dibasic acids, esters of saturated polyhydric alcohols, fatty acid esters, low molecular weight polyethylene glycols and sulfonamide resins and more specifically a plasticizer selected from the group consisting of diethyl adipate, dicapryl adipate, dimethoxyethyl adipate, diethoxyethyl, dimethoxyethoxy adipate, triethyl citrate, tris-n-butyl citrate, acetyl triethyl citrate, glycerol monoacetate, glycerol diacetate, glycerol triacetate, (ethoxycarbonyl) methyl methyl phthalate, bis(2 methoxyethyl) phthalate, diethylene glycol diacetate, triethylene glycol diacetate, glycerol triisopropionate, ethylene glycol dipropionate, diethylene glycol dipropionate, diethylene glycol
  • the plasticizer is a food-compliant plasticizer.
  • Food-compliant means compliant with applicable food additive and/or food contact regulations where the plasticizer is cleared for use or recognized as safe by at least one (national or regional) food safety regulatory agency (or organization), for example listed in the 21 CFR Food Additive Regulations or otherwise Generally Recognized as Safe (GRAS) by the US FDA.
  • GRAS Generally Recognized as Safe
  • Plasticizer in included into the cellulose acetate composition such that composition will flow, can be processed and can be thermoformed into three dimensional objects.
  • the cellulose acetate composition being either the dry cellulose acetate material with plasticizer contained therein as a flake or pellet, or as a mixture of cellulose acetate material with plasticizer as a separated component.
  • the plasticizer is present in the cellulose acetate composition an amount from any of 10 to 25 wt%; or 15 to 25 wt%, or 13- 20 wt% based on the total weight of the cellulose acetate composition.
  • the cellulose acetate, the plasticizer or both include compostable components.
  • the plasticizer includes triacetin, triethyl citrate, or polyethylene glycol.
  • the plasticizer can include additional additives. Additional additives include carriers, fillers, stabilizers, waxes, compatibilizers, cellulose acetate, composability promoters, anti-oxidants, antifungal agents, colorants, anti-fogging agents, aging modifiers such as glycerol monostearate, anti-static, impact modifiers, antibacterial agents, flame retardants, processing aids, and combinations thereof. [0034] Chemical foaming agent
  • Chemical foaming agents refer to those compositions which when heated, decompose or react at a certain temperature to form a gas.
  • Chemical foaming agents are a class of foaming agents that are often utilized in solid (normally as powder, flake, or pellets) or as liquid.
  • the chemical foaming agent is normally solid or liquid at room temperature.
  • the chemical foaming agent Upon heating beyond the decomposition temperature, the chemical foaming agent decomposes and releasing a gas into a mixture. Heating a blend allows the base matenal to flow and the chemical foaming agent to release gas.
  • the gas forms bubbles or cells in the melt.
  • the gas expands, and in turn causes the mixture to expand.
  • the cell structure remains. Different chemical foaming agent release gas at different rates and temperatures, and the choice of chemical foaming agent depends on the processing conditions, type of foam material, and the desired phy sical properties of the foam.
  • Chemical foaming agents tend to be dependent upon the temperature. Unlike physical blowing agents, chemical foaming agents can be added to a solid mixture before heating. In embodiments, the chemical foaming agent has a decomposition temperature of greater than any of 80°C, 100°C, 120°C or 140°C.
  • the cellulose acetate composition being at least cellulose acetate and 10-25 wt% plasticizer. Amounts of from 0.04 to 3 wt% of a chemical foaming agent is mixed with the cellulose acetate.
  • the chemical foaming agent may be introduced as a masterbatch with a carrier resin and other additives commonly used.
  • the chemical foaming agent is an endothermic or exothermic chemical foaming agent.
  • the chemical foaming agent includes sodium bicarbonate, citric acid, or both.
  • Chemical foaming agents are a class of foaming agents that are often utilized in solid (normally as powder, flake, or pellets) or as liquid.
  • the chemical foaming agent is normally solid or liquid at room temperature.
  • Heating a blend allows the base material to flow and the chemical foaming agent to release gas.
  • the gas forms bubbles or cells in the melt.
  • the gas expands, and in turn causes the mixture to expand.
  • the cell structure remains.
  • Different chemical foaming agent release gas at different rates and temperatures, and the choice of chemical foaming agent depends on the processing conditions, type of foam material, and the desired physical properties of the foam.
  • chemical foaming agents can be added to a solid mixture before heating.
  • the chemical foaming agent is 30-70 wt% sodium bicarbonate, citric acid, or both.
  • the chemical foaming agent includes 10-30, 15-25 or 19-21 wt% sodium bicarbonate.
  • the chemical foaming agent further includes 20-40, 25-35 or 29-31 wt% citnc acid.
  • the chemical foaming agent includes 10-30, 15-25 or 19-21 wt% sodium bicarbonate and 20-40, 25-35 or 29-31 wt% citric acid.
  • Sodium bicarbonate starts to decompose at around 160 °C, while citnc acid starts decomposing at around 210 °C.
  • citnc acid starts decomposing at around 210 °C.
  • the chemical foaming agent further comprises a carrier resm, additives, nucleating agents or additional chemical foaming agents.
  • a carrier resm Polyethy lene and polystyrene are known carrier resins.
  • the chemical foaming agent includes a biopolymer as a carrier resin.
  • Biopolymer carrier resins include BioPBS FD92PM available from Mitsubishi Chemical and CAPA 6500 a poly caprolactone available from Ingevity.
  • the biopolymer is compostable as defined herein.
  • the chemical foaming agent includes an alkaline earth metal combined with an acid such as citric acid or tartaric acid.
  • the chemical foaming agent further includes calcium carbonate.
  • the chemical foaming agent may further comprise nucleating agents.
  • Nucleating agents produce more cells in the foam than would be produced without the nucleating agent.
  • the nucleating agent selected from the group consisting of molecular sieve materials, titanium dioxide, perlite, and limestone.
  • the inclusion of certain nucleating agents can be problematic in reusing and recycling foams without additional process steps.
  • the mixture and the resulting foam includes less than any of 1.0 wt%, 0.8 wt%, 0.6 wt%, 0.4 wt%. 0.2 wt%. 0.1 wt%, 0.05 wt% or substantially no inert inorganic nucleating agent.
  • inert inorganic nucleating agents include molecular sieve materials, titanium dioxide, perlite, limestone, talc, silica, calcium carbonate, calcium fluoride, boron nitride, aluminum magnesium hydroxide, silica, silica gel, functionalized silica nanoparticles, silicon dioxide, titanium carbide, zirconium carbide, tungsten sulfide, zinc oxide, bentonite, or nucleating agents comprises a magnesium silicate, a silicon dioxide, a magnesium oxide, or combinations thereof.
  • the chemical foaming agent include additional additives.
  • Additional additives include carriers, fillers, stabilizers, waxes, compatibilizers, cellulose acetate, composability promoters, anti-oxidants, antifungal agents, colorants, anti-fogging agents, aging modifiers such as glycerol monostearate, anti-static, plasticizer, impact modifiers, antibacterial agents, flame retardants, processing aids, and combinations thereof.
  • a physical blowing agent is introduced to the heated mixture of the cellulose acetate composition and chemical foaming agent.
  • the physical blowing agent generates enough pressure to force the melt through an extruder.
  • the melt is cooled.
  • Physical blowing agents include, but are not limited to CO2, N2, supercritical CO2, unbranched or branched (C2- 6)alkane, propane, isobutane, N-butane, ethanol, cyclopentane or any combination thereof.
  • the physical blowing agent is introduced into the mixture at a rate of less than 10 wt%, 9 wt%, 8 wt%, 7 wt%, 6 wt%, 5 wt%, 4 wt%, 3 wt%, 2 wt%, 1 wt% based on the total weight of the mixture.
  • a cellulose acetate composition and a plasticizer are provided, mixed and heated in an extruder.
  • Screw type extruders are useful for introducing, mixing and heating materials.
  • Screw type extruders include single screw, multiple single screw extruders in tandem, corotating twin screw, counter-rotating twin screw, parallel twin screw and conical twin screw.
  • Screw type extruders utilize a pressure profile along the length of the screw to prevent blowing agent from backing up and exiting through upstream.
  • Twin screw extruders may be utilized for improved heat transfer, shear mixing and pressure profile control.
  • the cellulose acetate composition may include the plasticizer as part of the composition, plasticizer may be added the extruder, or both such that the plasticizer is homogeneously distributed throughout the mixture.
  • a chemical foaming agent is added to the mixture.
  • the chemical foaming agent may be included in the main feed line, included with the cellulose acetate mixture, or may be added to separate feed port.
  • the chemical foaming agent including sodium bicarbonate, citric acid or both.
  • a physical blowing agent is introduced to the heated mixture generating sufficient pressure to force the melted mixture through an extruder. The physical blowing agent cools the melted blend during the process.
  • a foam composition exits the extruder, which in embodiments is through a die.
  • the foam composition includes less than 0.1 wt%, 0.05 wt%, 0.01 wt% or substantially inert inorganic nucleating agent.
  • the extruded foam has a density of less than any of 0.10, 0.08 or 0.06 g/cc as measured in accordance with ASTM D-1505; the foam having an average cell size of less than any of the following 300, 250, 200, 150, 120, 100, or 80 microns in accordance with ASTM D-3756.
  • the foam is extruded as a cylindrical rod.
  • the cylindrical rod may be slit and then laid flat to form a laid flat sheet of the extruded foam.
  • the foam is extruded through an annular or sheet die.
  • the foam sheet is then wound up and stored for later processing. The storage process ages the foam allowing for expansion to complete and allowing for foaming and blowing agents to dissipate. In embodiments, winding up the sheet is optional.
  • the foam sheet may then be sent to a thermoforming process.
  • the thermoforming process utilizes heat and pressure to form the sheet into a three-dimensional packaging article. Tooling may be utilized to form the sheet into the desired shape.
  • the three-dimensional packaging article is a tray.
  • the three-dimensional packaging article comprises a flange, a cavity and at least one wall.
  • foamed trays are manufactured in a two-step process. In a first step, foamed sheets are obtained in an extrusion process. In the second step, the foamed sheets are thermoformed into the desired shape. In another embodiment, these steps are combined into a single process.
  • Fig. 1 is an exemplary embodiment of making a foam.
  • the cellulose acetate composition and plasticizer are dried prior mixing. It is understood that the cellulose acetate and plasticizer may be integrated into the same material or be different components.
  • the cellulose acetate and plasticizer are then mixed with a chemical foaming agent. This may be in a separate mixer or as part an extruder, for example a screw-type extruder. Once in the extruder, the materials melt and flow through the extruder. The heat activates the chemical foaming agent to begin the foaming process. Physical blowing agent is introduced into the extruder and a foam rod exits the extruder die. The foam may continue to expand once it leaves the die. To prevent over expansion, the foam should cool relatively quickly near the die exit.
  • Fig. 3 is another exemplary embodiment of making a foam.
  • the resin includes a cellulose acetate composition and plasticizer which are dried prior mixing. It is understood that the cellulose acetate and plasticizer may be integrated into the same material or be different components. The drying may not be required depending on the initial resin condition.
  • the cellulose acetate and plasticizer are then mixed with a chemical foaming agent. This may be in a separate mixer or as part an extruder, for example a screw-type extruder. Once in the extruder, the materials melt and flow through the extruder. As the materials are heated in the extruder, the chemical foaming agent is activated to begin the foaming process.
  • One or more physical blowing agents are introduced into the extruder and a foam exits the extruder die, such as a sheet or annular die.
  • the foam may continue to expand once it leaves the die. To prevent over expansion, the foam should cool relatively quickly near the die exit.
  • the annular foam may be pulled onto a cooling mandrel which cools and shapes the foam.
  • FIG. 4 a schematic cutaway view of an exemplary foam extruder is shown.
  • Resin 101 is fed into the extruder 110 via hopper 112.
  • the resin 101 includes cellulose acetate along with plasticizer.
  • the plasticizer may be added as a separate component or may be integrated with the cellulose acetate material as a pellet, flake or granular material.
  • the resin may further include chemical foaming agent or other additives such as carriers, fillers, stabilizers, waxes, compatibilizers, composability promoters, antioxidants, antifungal agents, colorants, pigments, anti-fogging agents, aging modifiers such as glycerol monostearate, anti-static, impact modifiers, antibacterial agents, flame retardants, processing aids, and combinations thereof.
  • chemical foaming agent or other additives such as carriers, fillers, stabilizers, waxes, compatibilizers, composability promoters, antioxidants, antifungal agents, colorants, pigments, anti-fogging agents, aging modifiers such as glycerol monostearate, anti-static, impact modifiers, antibacterial agents, flame retardants, processing aids, and combinations thereof.
  • additives such as carriers, fillers, stabilizers, waxes, compatibilizers, composability promoters, antioxidants, antifungal agents, colorants, pigments, anti-fogging agents,
  • the cellulose acetate and plasticizer may be loaded in a first hopper at a first point along the extruder, while a chemical foaming agent is loaded in at a second point along the extruder and further additives are loaded at a third point along the extruder.
  • all materials can be mixed and loaded along multiple hoppers and loaded along multiple points along the extruder.
  • the extruder 110 is depicted as a single screw type extruder. Other extruder types, such multiple single screw extruders in tandem, corotating twin screw, counter-rotating twin screw, parallel twin screw and conical twin screw may be employed.
  • One or more heaters are employed to raise the temperature of the resin. As the resin melts and reaches the decomposition temperature of the chemical foaming agent the chemical foaming agent begins to produce gas causing the melted resin to foam.
  • the resin can include additional additives.
  • Additional additives include carriers, fillers, plasticizers, stabilizers, waxes, compatibilizers, composability promoters, anti-oxidants, antifungal agents, colorants, anti-fogging agents, aging modifiers such as glycerol monostearate, anti-static, impact modifiers, antibacterial agents, flame retardants, processing aids, and combinations thereof.
  • Such additional additives can be blended with and formed with the resin material (e.g. as flake or pellet), or can be added as a separate component prior to extrusion. The total addition of additives can by 10% by weight as compared to the resin mixture.
  • a blowing agent 102 is introduced into the mixing portion 113 of the extruder 110.
  • the extruder 110 maintains a pressure profile along the length of the screw to prevent blowing agent from backing up and exiting through upstream points such as hopper 112.
  • the pressure inside the extruder aids in moving the melted resin and blowing agents toward and through the die 130.
  • the melted resin and physical blowing agents move along a colling portion 116.
  • the cooling portion aids in reducing overexpansion prior to the melt existing the die.
  • the melted resin is further mixed in a mixer 120.
  • the mixer is a static mixer.
  • mixer 120 is depicted as being located after the cooling portion 116, it is understood that in embodiments, the mixer 120 is placed before the cooling portion 116. In another embodiment, a first mixer is placed before the cooling portion 116 and a second mixer is placed after the cooling portion 116. In embodiments utilizing multiple mixers, the mixers may be the same or different mixing elements.
  • Dried and cooled materials were provided to a screw type extruder.
  • the material is dried at 60°C for at least 6 hours prior to processing.
  • CAI and CFA were introduced in the main feed line.
  • NA was added post melt.
  • Physical blowing agent was introduced downstream of the NA and a foam was extruded from the die nozzle of a round die extruder to form a cylindrical shaped foam sample.
  • Foams were made in a corotating twin screw type extruder in the composition as set forth in Table 2.
  • the amount of CFA included in Table 2 includes the carrier resin.
  • the effective amount of chemical foaming agent being about 50% of the composition.
  • the properties of the foams were measured and reported in Table 3 below
  • Foams 1 and 2 had processing issues as noted in Table 3. Foam 3 continued to extrude foam for about 1 hour with no issues. It was surprising to see that removing talc from the formulation and only using the chemical foaming agent with the physical blowing agent would provide vastly superior density and cell size. Fig. 2 depicts an image of Foam 3.
  • Embodiment A A foam comprising: a. 72-84 wt% cellulose acetate b. 10-25 wt% plasticizer c. 0.04-3 wt% of a chemical foaming agent the foam having a density of less than any of 0.10, 0.08 or 0.06 g/cc as measured in accordance with ASTM D1505; the foam having an average cell size of less than any of the following 300, 250, 200, 150, 120, 100, or 80 microns in accordance with ASTM D-3756.
  • B The foam of embodiment A wherein the cellulose acetate has a bio content of at least 50%, 55%, 60% or 65% measured in accordance with ASTM D-6866.
  • a method for making a foam comprising the steps of: a. mixing a blend of 72-84 wt% cellulose acetate, 15-25 wt% of a plasticizer and 0.04- 3 wt% of a chemical foaming agent, all wt% based on the total weight of the mixed blend; b. heating the blend; c. introducing a physical blowing agent to the blend; d.
  • the foam having a density of less than any of 0.10, 0.08 or 0.06 g/cc as measured in accordance with ASTM D1505; the foam having an average cell size of less than any of the following 300, 250, 200, 150, 120, 100, or 80 microns in accordance with ASTM D-3756.
  • N The method of embodiments J-M wherein the blend is heated to at least 165, 170, 175 or 180 °C.
  • R The method of embodiments Q wherein the three-dimensional packaging article comprises a flange, a cavity and at least one wall.
  • a foam packaging article comprising: a. a foam formed into a three-dimensional packaging article, the foam comprising: i. 72-84 wt% cellulose acetate ii. 10-25 wt% plasticizer iii. 0.04-3 wt% of a chemical foaming agent (or define in amount of sodium bicarbonate the foam having a density of less than any of 0. 10, 0.08 or 0.06 g/cc as measured in accordance with ASTM DI 505; the foam having an average cell size of less than any of the following 300, 250, 200, 150, 120, 100, or 80 microns in accordance with ASTM D-3756 in any of the MD, TD or thickness; b. a product situated on the three-dimensional packaging article.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Health & Medical Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Organic Chemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Manufacture Of Porous Articles, And Recovery And Treatment Of Waste Products (AREA)

Abstract

L'invention concerne une mousse durable contenant 72 à 84 % en poids d'acétate de cellulose, 10 à 25 % en poids d'un plastifiant et 0,04 à 3 % en poids d'un agent moussant chimique. La mousse présente une masse volumique inférieure à l'une quelconque des valeurs 0,10, 0,08 ou 0,06 g/cm3, mesurée selon la norme ASTM D1505. La mousse présente une grosseur moyenne de cellule inférieure à l'une quelconque des valeurs suivantes : 300, 250, 200, 150, 120, 100 ou 80 micromètres selon ASTM D-3756.
PCT/US2023/021459 2022-05-09 2023-05-09 Mousse durable WO2023220007A1 (fr)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2024064815A1 (fr) * 2022-09-23 2024-03-28 Eastman Chemical Company Compositions moussantes d'acétate de cellulose comprenant du dioxyde de carbone et un agent gonflant chimique et mousses formées à partir de celles-ci

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6221924B1 (en) * 1997-09-05 2001-04-24 Teijin Limited Biodegradable cellulose acetate foam and process for its production
CN105585740A (zh) * 2016-03-08 2016-05-18 云南中烟工业有限责任公司 一种醋酸纤维素开孔微孔发泡材料的制备方法
WO2021150540A1 (fr) * 2020-01-20 2021-07-29 Eastman Chemical Company Compositions biodégradables et articles fabriqués à partir d'acétate de cellulose

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6221924B1 (en) * 1997-09-05 2001-04-24 Teijin Limited Biodegradable cellulose acetate foam and process for its production
CN105585740A (zh) * 2016-03-08 2016-05-18 云南中烟工业有限责任公司 一种醋酸纤维素开孔微孔发泡材料的制备方法
WO2021150540A1 (fr) * 2020-01-20 2021-07-29 Eastman Chemical Company Compositions biodégradables et articles fabriqués à partir d'acétate de cellulose

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2024064815A1 (fr) * 2022-09-23 2024-03-28 Eastman Chemical Company Compositions moussantes d'acétate de cellulose comprenant du dioxyde de carbone et un agent gonflant chimique et mousses formées à partir de celles-ci

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