WO2022220827A1 - Applications d'emballage de soie - Google Patents

Applications d'emballage de soie Download PDF

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Publication number
WO2022220827A1
WO2022220827A1 PCT/US2021/027333 US2021027333W WO2022220827A1 WO 2022220827 A1 WO2022220827 A1 WO 2022220827A1 US 2021027333 W US2021027333 W US 2021027333W WO 2022220827 A1 WO2022220827 A1 WO 2022220827A1
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WO
WIPO (PCT)
Prior art keywords
silk
substrate
packaging product
coating
solution
Prior art date
Application number
PCT/US2021/027333
Other languages
English (en)
Inventor
Adam M. BEHRENS
Sezin YIGIT
Laith M. ABU-TALEB
Lester Cheuk-Yin CHONG
Colin D. PRESTON
Original Assignee
Cambridge Crops, Inc.
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.)
Filing date
Publication date
Application filed by Cambridge Crops, Inc. filed Critical Cambridge Crops, Inc.
Priority to PCT/US2021/027333 priority Critical patent/WO2022220827A1/fr
Publication of WO2022220827A1 publication Critical patent/WO2022220827A1/fr

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D189/00—Coating compositions based on proteins; Coating compositions based on derivatives thereof
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B23/00—Layered products comprising a layer of cellulosic plastic substances, i.e. substances obtained by chemical modification of cellulose, e.g. cellulose ethers, cellulose esters, viscose
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • B32B27/30—Layered products comprising a layer of synthetic resin comprising vinyl (co)polymers; comprising acrylic (co)polymers
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • B32B27/32—Layered products comprising a layer of synthetic resin comprising polyolefins
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • B32B27/36—Layered products comprising a layer of synthetic resin comprising polyesters
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B29/00—Layered products comprising a layer of paper or cardboard
    • B32B29/08—Corrugated paper or cardboard
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B9/00—Layered products comprising a layer of a particular substance not covered by groups B32B11/00 - B32B29/00
    • B32B9/02—Layered products comprising a layer of a particular substance not covered by groups B32B11/00 - B32B29/00 comprising animal or vegetable substances, e.g. cork, bamboo, starch
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B9/00—Layered products comprising a layer of a particular substance not covered by groups B32B11/00 - B32B29/00
    • B32B9/04—Layered products comprising a layer of a particular substance not covered by groups B32B11/00 - B32B29/00 comprising such particular substance as the main or only constituent of a layer, which is next to another layer of the same or of a different material
    • B32B9/041—Layered products comprising a layer of a particular substance not covered by groups B32B11/00 - B32B29/00 comprising such particular substance as the main or only constituent of a layer, which is next to another layer of the same or of a different material of metal
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B9/00—Layered products comprising a layer of a particular substance not covered by groups B32B11/00 - B32B29/00
    • B32B9/04—Layered products comprising a layer of a particular substance not covered by groups B32B11/00 - B32B29/00 comprising such particular substance as the main or only constituent of a layer, which is next to another layer of the same or of a different material
    • B32B9/045—Layered products comprising a layer of a particular substance not covered by groups B32B11/00 - B32B29/00 comprising such particular substance as the main or only constituent of a layer, which is next to another layer of the same or of a different material of synthetic resin
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B9/00—Layered products comprising a layer of a particular substance not covered by groups B32B11/00 - B32B29/00
    • B32B9/04—Layered products comprising a layer of a particular substance not covered by groups B32B11/00 - B32B29/00 comprising such particular substance as the main or only constituent of a layer, which is next to another layer of the same or of a different material
    • B32B9/06—Layered products comprising a layer of a particular substance not covered by groups B32B11/00 - B32B29/00 comprising such particular substance as the main or only constituent of a layer, which is next to another layer of the same or of a different material of paper or cardboard
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2307/00—Properties of the layers or laminate
    • B32B2307/40—Properties of the layers or laminate having particular optical properties
    • B32B2307/412—Transparent
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2307/00—Properties of the layers or laminate
    • B32B2307/40—Properties of the layers or laminate having particular optical properties
    • B32B2307/414—Translucent
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2307/00—Properties of the layers or laminate
    • B32B2307/70—Other properties
    • B32B2307/716—Degradable
    • B32B2307/7163—Biodegradable
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2307/00—Properties of the layers or laminate
    • B32B2307/70—Other properties
    • B32B2307/724—Permeability to gases, adsorption
    • B32B2307/7242—Non-permeable
    • B32B2307/7244—Oxygen barrier
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2307/00—Properties of the layers or laminate
    • B32B2307/70—Other properties
    • B32B2307/724—Permeability to gases, adsorption
    • B32B2307/7242—Non-permeable
    • B32B2307/7246—Water vapor barrier
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2435/00—Closures, end caps, stoppers
    • B32B2435/02—Closures, end caps, stoppers for containers
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2439/00—Containers; Receptacles
    • B32B2439/40—Closed containers
    • B32B2439/46—Bags
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2439/00—Containers; Receptacles
    • B32B2439/40—Closed containers
    • B32B2439/60—Bottles
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2439/00—Containers; Receptacles
    • B32B2439/40—Closed containers
    • B32B2439/62—Boxes, cartons, cases
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2439/00—Containers; Receptacles
    • B32B2439/70—Food packaging
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2553/00—Packaging equipment or accessories not otherwise provided for
    • 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
    • C08J2389/00—Characterised by the use of proteins; Derivatives thereof
    • 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
    • C08J5/00—Manufacture of articles or shaped materials containing macromolecular substances
    • C08J5/18—Manufacture of films or sheets

Definitions

  • compositions and methods for preparing silk films for use in food packaging pertain to compositions and methods for preparing silk films for use in food packaging.
  • Bio-based packaging materials provide an alternative to other packaging materials, such as plastic, and can decrease carbon dioxide levels, reduce greenhouse gas emission levels, and consume less energy during the manufacturing cycle.
  • Embodiments of the present disclosure represent significant environmental and commercial value by increasing revenue through improved distribution, reducing waste, and decreasing costs associated with cold storage and transport.
  • Exemplary compositions of the present disclosure comprise silk films and packaging coatings as a replacement for traditional food packaging, such as single-use plastic packaging, and/or to extend the shelf-life of foods.
  • the natural bio-based silk coatings of the present disclosure may be odorless, low cost, edible, compostable, come from a renewable source, removable from the packaging for recycling, and are biodegradable.
  • the silk films and packaging coatings may prolong the shelf-life, enhance or maintain the quality and safety, and/or provide indication of and regulate the freshness of food products.
  • FIG. 1 shows an example of transparent (also known as translucent) paper. This paper may be prepared as disclosed herein to create a product that is permeated with silk.
  • FIG. 2 shows another view of transparent paper, highlighting a section of increased thickness to better illustrate the transparency achieved using the silk solution to form a coating
  • FIGs. 3a and 3b shows the same piece of transparent paper.
  • FIG. 3a shows the transparent paper sitting on a tabletop
  • FIG. 3b shows the flexibility of the same transparent paper, as the paper may bend even though the silk has permeated the paper.
  • the flexibility of the transparent paper may be improved by including additives in the silk solution, including plasticizers.
  • FIG. 3b shows a piece of paper that included plasticizers in the silk solution
  • FIGs. 4a-4b and 5a-5b show different methods for applying a silk solution to a piece of paper to create a silk coating.
  • FIG. 4a shows a substrate that was sprayed with a silk solution.
  • Fig. 4b shows a substrate with a portion coated with a silk solution by spraying that has dried and another portion that has no silk solution applied to the substrate.
  • FIG. 5a shows a doctor blade that may be used to apply silk solution to a substrate, which is paper in this example.
  • Fig. 5b shows the silk solution after it is spread across the paper by the doctor blade.
  • FIG. 6 shows the end result of one potential method of preparing a free standing film, where a free-standing silk film is attached to a frame, in this case an embroidery hoop, prior to separation from the frame.
  • FIG. 7 shows an example of free-standing silk film used to encapsulate a food composition in a package made entirely of free-standing silk film.
  • FIG. 8 shows silk laminated paper after lamination has been completed.
  • FIG. 9 shows a Cobb test result of a substrate with and without a coating of silk solution.
  • FIG. 10 shows a plot of the results of the Cobb test in FIG. 9.
  • FIG. 11 shows the results of a second Cobb test, where different amounts of silk solution of different molecular weights (M ) are applied to paper.
  • FIG. 12 shows the results of a fourth Cobb test as a graph, where different amounts of silk solution of different molecular weights (M ) are applied to paper.
  • FIG. 13 shows a packaging product with a window in one side that has a silk-based covering over the window.
  • A bag; B: window.
  • FIG. 14 shows a packaging product with a window in the top side that has a silk-based covering over the window.
  • A bag; B: window.
  • FIG. 15 shows an exemplary graph of the molecular weights (MW) of silk fibroin fragments in an exemplary silk film and/or coating.
  • FIG. 16 shows an exemplary graph of the molecular weights (MW) of silk fibroin fragments in an exemplary silk film and/or coating.
  • the terms "about” or “comprising essentially of” refer to a value or composition that is within an acceptable error range for certain value or composition as determined by one of ordinary skill in the art, which will depend in part on how the value or composition is measured or determined, i.e. , the limitations of the measurement system.
  • “about” or “comprising essentially of” may mean within 1 or more than 1 standard deviation per the practice in the art.
  • “about” or “comprising essentially of” may mean a range of up to 10% (i.e., ⁇ 10%).
  • about 3 mg may include any number between 2.7 mg and 3.3 mg (for 10%).
  • the terms may mean up to an order of magnitude or up to 5-fold of a value.
  • the meaning of "about” or “comprising essentially of” include an acceptable error range for that value or composition.
  • Any concentration range, percentage range, ratio range, or integer range includes the value of any integer within the recited range and, when appropriate, fractions thereof (such as one-tenth and one- hundredth of an integer), unless otherwise indicated.
  • the terms “or more”, “at least”, “more than”, and the like, e.g., “at least one” include but not be limited to at least 1 , 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 , 12, 13, 14, 15, 16, 17, 18, 1920, 21 , 22, 23, 24, 25, 26, 27, 28, 29, 30, 31 , 32, 33, 34, 35, 36, 37, 38, 39, 40, 41 , 42, 43, 44, 45, 46, 47, 48, 49, 50, 51 , 52, 53, 54, 55, 56, 57, 58, 59, 60, 61 , 62, 63, 64,
  • any greater number or fraction in between includes each value less than the stated value.
  • “no more than 100” includes 100, 99, 98, 97, 96, 95, 94, 93, 92, 91 ,
  • the terms “plurality”, “at least two”, “two or more”, “at least second”, and the like include but not limited to at least 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 , 12, 13, 14, 15, 16, 17, 18, 1920, 21 , 22, 23, 24, 25, 26, 27, 28, 29, 30, 31 , 32, 33, 34, 35, 36, 37, 38, 39, 40, 41 , 42, 43, 44, 45, 46, 47, 48, 49, 50, 51 , 52, 53, 54, 55, 56, 57, 58, 59, 60, 61 , 62, 63, 64, 65, 66, 67, 68, 69, 70, 71 , 72, 73, 74, 75, 76, 77, 78, 79, 80, 81 , 82, 83, 84, 85, 86, 87, 88,
  • the term “about” refers to a value or composition that is within an acceptable error range for the particular value or composition as determined by one of ordinary skill in the art, which will depend in part on how the value or composition is measured or determined, i.e. , the limitations of the measurement system. For example, “about” or “approximately” may mean within one or more than one standard deviation per the practice in the art. “About” or “approximately” may mean a range of up to 10% (i.e., ⁇ 10%).
  • “about” may be understood to be within 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, 1 %, 0.5%, 0.1 %, 0.05%, 0.01 %, or 0.001% greater or less than the stated value.
  • about 5 mg may include any amount between 4.5 mg and 5.5 mg.
  • the terms may mean up to an order of magnitude or up to 5-fold of a value.
  • any concentration range, percentage range, ratio range or integer range is to be understood to be inclusive of the value of any integer within the recited range and, when appropriate, fractions thereof (such as one-tenth and one- hundredth of an integer), unless otherwise indicated.
  • Silk fibroin is a structural protein that may be produced and extracted from silkworm, spiders, or other insects. It may also be otherwise generated synthetically, transgenically and other genetically engineered silks (e.g., silks from bacteria, yeast, mammalian cells, transgenic animals, or transgenic plants). In some embodiments, silk fibroin may be derived from other sources such as spiders, other silkworms, bees, and bioengineered variants thereof. In some embodiments, silk fibroin may be extracted from a gland of silkworm or transgenic silkworms. In some embodiments, silk fibroin is free, or essentially free of sericin, i.e. , silk fibroin is a substantially sericin-depleted silk fibroin. Any type of silk fibroin may be used according to aspects of the present disclosure.
  • Silk fibroin is naturally produced by species such as, without limitation, Bombyx mandarina, Bombyx mori, Bombyx sinesis, Anaphe moloneyi, Anaphe panda, Anaphe reticulate, Anaphe ambrizia, Anaphe carteri, Anaphe venata, Anapha infracta, Antheraea assamensis, Antheraea assama, Antheraea mylitta, Antheraea pernyi, Antheraea yamamai, Antheraea polyphemus, Antheraea oculea, Anisota senatoria, Apis mellifera, Araneus diadematus, Araneus cavaticus, Automeris io, Atticus atlas, Copaxa multifenestrata, Coscinocera hercules, Callosamia promethea, Eupackardia calleta,
  • Silk fibroin s unique properties are derived from its structure, consisting of hydrophobic blocks separated by hydrophilic spacers. In its natural state, silk fibroin is organized in beta-sheets, which are formed by highly ordered crystalline regions alternated by amorphous regions. This unique structure results in high levels of strength and toughness for silk fibroin-based materials.
  • the wide range of forms into which silk fibroin solution may be processed make it attractive for several high-tech applications, including scaffolds for tissue engineering, bone screws for fixation, and drug depots for therapeutic delivery.
  • the Bombyx mori silkworm starts its life in a cocoon.
  • a single cocoon may be made up of hundreds of meters of silk.
  • the cocoon itself is made up largely by two proteins: fibroin and sericin. With the other component parts, the fibroin helps regulate gas diffusion in and out of the cocoon. Similarly, such regulation is achievable with silk fibroin-based materials. This is applicable to extending the shelf-life of perishables given that the main modes of spoilage relate to oxidation, degradation, and dehydration.
  • the tunability of silk fibroin allows for its versatility of application across different produce types.
  • Silk fibroin forms polymeric coatings with varying degree of solubility and breathability.
  • Fine-tuning is enabled by different production parameters such as concentration, shear force, additives, temperature, and postprocessing. By tuning these parameters, silk-fibroin structural organization may be controlled. Structural differences ultimately affect crystallinity, elasticity, solubility and porosity which in turn alter the gas and water diffusion behavior, as well as reduce microbial growth rates.
  • the starting material for fibroin may be cocoons, cocoon filaments, raw silk, silk fabrics, silk yarn, degummed silk, any other partially cleaned silk, etc. This may also include short fragments of raw or sericin-depleted silk.
  • the silk fibroin is in a powder.
  • the silk fibroin is in a solution.
  • the silk solutions are as described in U.S. Patent Application Publication No. US 2020-0178576 A1 , incorporated herein by reference in its entirety.
  • the silk compositions used for the silk films and silk-coated packaging materials contain at least one silk protein, including fibroin, fibroin-related protein, or modified fibroin protein.
  • the silk protein in these compositions may range from about 0.1% (w/w) to about 1% (w/w) from about 1 % (w/w) to about 5% (w/w), from about 5% (w/w) to about 10% (w/w), from 10% (w/w) to about 100% (w/w), from about 20% (w/w) to about 95% (w/w), from about
  • the percent silk in the composition is less than 60%. In an embodiment, the percent silk (w/w) in the composition is less than 25%. In an embodiment, the percent silk in the composition is less than 20%. In an embodiment, the percent silk in the composition is less than 19%. In an embodiment, the percent silk in the composition is less than 18%. In an embodiment, the percent silk in the composition is less than 17%. In an embodiment, the percent silk in the composition is less than 16%. In an embodiment, the percent silk in the composition is less than 15%.
  • the percent silk in the composition is less than 14%. In an embodiment, the percent silk in the composition is less than 13%. In an embodiment, the percent silk in the composition is less than 12%. In an embodiment, the percent silk in the composition is less than 11 %. In an embodiment, the percent silk in the composition is less than 10%. In an embodiment, the percent silk in the composition is less than 9%. In an embodiment, the percent silk in the composition is less than 8%. In an embodiment, the percent silk in the composition is less than 7%. In an embodiment, the percent silk in the composition is less than 6%. In an embodiment, the percent silk in the composition is less than 5%. In an embodiment, the percent silk in the composition is less than 4%. In an embodiment, the percent silk in the composition is less than 3%.
  • the percent silk in the composition is less than 2%. In an embodiment, the percent silk in the composition is less than 1 %. In an embodiment, the percent silk in the composition is less than 0.9%. In an embodiment, the percent silk in the composition is less than 0.8%. In an embodiment, the percent silk in the composition is less than 0.7%. In an embodiment, the percent silk in the composition is less than 0.6%. In an embodiment, the percent silk in the composition is less than 0.5%. In an embodiment, the percent silk in the composition is less than 0.4%. In an embodiment, the percent silk in the composition is less than 0.3%. In an embodiment, the percent silk in the composition is less than 0.2%. In an embodiment, the percent silk in the composition is less than 0.1 %. Higher or lower silk protein content may also be possible.
  • the solvent content in the silk compositions may range from about 0% (w/w) to about 60% (w/w), from about 0.5% (w/w) to about 50% (w/w), from about 1% (w/w) to about 40% (w/w), from about 1 % (w/w) to about 30% (w/w), from about 1 % (w/w) to about 20% (w/w), from about 1 % (w/w) to about 15% (w/w), from about 1 % (w/w) to about 12% (w/w), from about 2% (w/w) to about 10% (w/w), from about 3% (w/w) to about 9% (w/w), from about 4% (w/w) to about 8% (w/w), from about 5% (w/w) to about 7% (w/w), from about 6% (w/w) to about 12% (w/w), from about 5% (w/w) to about 10% (w/w), or from about 5% (w/w) to
  • the silk used for generation of the present compositions is substantially depleted of its sericin content (i.e. , less than about 4% (w/w) residual sericin in the final extracted silk). Alternatively, higher concentrations of residual sericin may be left on the silk following extraction or the extraction step may be omitted.
  • the sericin-depleted silk fibroin has, e.g., less than about 1% (w/w), less than about 2% (w/w), less than about 3% (w/w), less than about 4% (w/w), less than about 5% (w/w), less than about 10% (w/w), less than about 15% (w/w), about 1 % (w/w) to about 2% (w/w), about 1 % (w/w) to about 3% (w/w), or about 1 % (w/w) to about 4% (w/w) residual sericin.
  • the silk fibroin may be modified for different applications and/or desired mechanical or chemical properties (e.g., to facilitate formation of a gradient of an additive (e.g., an active agent) in silk fibroin-based materials).
  • an additive e.g., an active agent
  • One of skill in the art may select appropriate methods to modify silk fibroins, e.g., depending on the side groups of the silk fibroins, desired reactivity of the silk fibroin and/or desired charge density on the silk fibroin.
  • modification of silk fibroin may use the amino acid side chain chemistry, such as chemical modifications through covalent bonding, or modifications through charge-charge interaction.
  • Exemplary chemical modification methods include, but are not limited to, carbodiimide coupling reaction, diazonium coupling reaction, avidin- biotin interaction and pegylation with chemically-active or activated derivatives of the PEG polymer.
  • Silk fibroin may also be modified through gene modification to alter functionalities of the silk protein.
  • the silk fibroin may be genetically modified, which may provide for further modification of the silk such as the inclusion of a fusion polypeptide comprising a fibrous protein domain and a mineralization domain, which may be used to form an organic-inorganic composite.
  • the silk fibroin-based material may be combined with a chemical that affects flexibility of the material.
  • the silk fibroin comprises silk fibroin monomers, polymers, and/or fragments.
  • the term silk fibroin fragments also includes assemblies of silk fibroin fragments.
  • the silk film and/or coating comprises a specific percentage (weight/volume) of silk fibroin fragments.
  • a specific percentage of the silk fibroin fragments have a specific molecular weight. (MW).
  • MW molecular weight
  • M weight average molecular weight
  • gel permeation chromatography could be used to acquire the molecular weight (MW) of silk fibroin fragments and the weight average molecular weight (M ) of the silk.
  • FIGs. 15 and 16 illustrate two different graphs of the molecular weights of silk fibroin fragments present in a silk film and/or coating.
  • the X axis represents molecular weight (MW)
  • the Y axis represents intensity (e.g., the number of silk fibroin fragments with the same molecular weight).
  • the blue bar illustrates a molecular weight (MW) range (e.g., 50 kDa to 100 kDA) that includes a certain percentage (e.g.
  • FIG. 15 has one peak and FIG. 16 has two peaks.
  • a graph of the molecular weights (MW) of a silk film and/or coating could include more than two peaks.
  • the number of peaks is not limiting and does not impact the percentages of silk fibroin fragments with a specific molecular weight (MW) as discussed herein.
  • more than about 1 % of the silk fibroin fragments have a molecular weight (MW) above 300 kilodaltons (kDa)
  • more than about 5% of the silk fibroin fragments have a molecular weight (MW) above 300 kDa
  • more than about 10% of the silk fibroin fragments have a molecular weight (MW) above 300 kDa
  • more than about 15% of the silk fibroin fragments have a molecular weight (MW) above 300 kDa
  • more than about 20% of the silk fibroin fragments have a molecular weight (MW) above 300 kDa
  • more than about 25% of the silk fibroin fragments have a molecular weight (MW) above 300 kDa
  • more than about 30% of the silk fibroin fragments have a molecular weight (MW) above 300 kDa
  • more than about 35% of the silk fibroin fragments have a molecular weight (MW) above 300 kDa, more than about
  • more than about 1 % of the silk fibroin fragments have a molecular weight (MW) above 400 kDa, more than about 5% of the silk fibroin fragments have a molecular weight (MW) above 400 kDa, more than about 10% of the silk fibroin fragments have a molecular weight (MW) above 400 kDa, more than about 15% of the silk fibroin fragments have a molecular weight (MW) above 400 kDa, more than about 20% of the silk fibroin fragments have a molecular weight (MW) above 400 kDa, more than about 25% of the silk fibroin fragments have a molecular weight (MW) above 400 kDa, more than about 30% of the silk fibroin fragments have a molecular weight (MW) above 400 kDa, more than about 35% of the silk fibroin fragments have a molecular weight (MW) above 400 kDa, more than about 40% of the silk fibroin fragment
  • between about 1 % and about 30% of the silk fibroin fragments have a molecular weight (MW) above 300 kDa, between about 10% and about 30% of the silk fibroin fragments have a molecular weight (MW) above 300 kDa, between about 10% and about 50% of the silk fibroin fragments have a molecular weight (MW) above 300 kDa, between about 10% and about 75% of the silk fibroin fragments have a molecular weight (MW) above 300 kDa, between about 10% and about 95% of the silk fibroin fragments have a molecular weight (MW) above 300 kDa, between about 15% and about 30% of the silk fibroin fragments have a molecular weight (MW) above 300 kDa, between about 30% and about 50% of the silk fibroin fragments have a molecular weight (MW) above 300 kDa, between about 50% and about 90% of the silk fibroin fragments have a molecular weight (MW) above 300 kDa
  • between about 1 % and about 60% of the silk fibroin fragments have a molecular weight (MW) above 400 kDa, between about 1 % and about 20% of the silk fibroin fragments have a molecular weight (MW) above 400 kDa, between about 1 % and about 30% of the silk fibroin fragments have a molecular weight (MW) above 400 kDa, between about 5% and about 20% of the silk fibroin fragments have a molecular weight (MW) above 400 kDa, between about 30% and about 60% of the silk fibroin fragments have a molecular weight (MW) above 400 kDa, between about 35% and about 55% of the silk fibroin fragments have a molecular weight (MW) above 400 kDa, between about 35% and about 75% of the silk fibroin fragments have a molecular weight (MW) above 400 kDa, between about 35% and about 85% of the silk fibroin fragments have a
  • the fibroin fragments comprise a weight average molecular weight (M ) from about 1 kDa to about 600 kDa. In some embodiments, the molecular weight (MW) of the silk fibroin fragments may range from about 10 kDa to about 1000 kDa. In some embodiments, the silk films and/or coating comprise silk fibroin compositions as described in U.S. Patent Application Publication No. 2020-0178576 A1 , incorporated herein by reference in its entirety.
  • Silk films and packaging coatings may be designed for different storage conditions or products of interest.
  • One embodiment is directed to a packaging composition wherein the silk film is transparent.
  • the film may be flexible or it may be rigid.
  • the silk film is a pure silk protein film. In some embodiments, the silk film is a composite. In some aspects, the silk film may be comprised of silk fibroin.
  • the silk fibroin may be isolated from silk sericin and the protein coat through the Ajisawa method or through other methods using water and salts, including chaotropic salts.
  • silk fibroin may be prepared according to the method described in Marelli, B., Brenckle, M., Kaplan, D. et al. Silk Fibroin as Edible Coating for Perishable Food Preservation. Sci Rep 6, 25263 (2016). https://doi.orq/10.1038/srep25263, incorporated herein by reference in its entirety.
  • the silk fibroin may be as described in US 2020-0178576 A1 , incorporated herein by reference in its entirety.
  • the silk fibroin may be a dried powder.
  • the silk fibroin may be in liquid form.
  • the solution may comprise the silk fibroin powder mixed with a solvent.
  • the solvent may be a liquid.
  • the solvent may be an acid with a pH under 6.0.
  • the solvent may be an alcohol or water.
  • the solvent may be acetic acid.
  • the silk fibroin powder or solution may be in a mixture containing an additive.
  • the additives may be plasticizers.
  • the additives may be surfactants.
  • the additive may be sorbitol, glycerol, xylitol, polyethylene glycol, mannitol, isomalt, sugars, collagen, cellulose, or lipids.
  • the additives may be pore fillers, including for example, food residuals (e.g., rice husks, corn husks, chitosan, citrus limetta peels, bran filler), clays, cellulose (e.g., microfibrillated, hardwood fibers, softwood fibers, bamboo, wheat), soy, and the like.
  • the liquid solvent for the silk fibroin may contain an additive.
  • both the silk fibroin powder mixture and the liquid solvent may contain additives.
  • the silk fibroin may be emulsified with the additive prior to being mixed into the solution.
  • liquid silk fibroin may be mixed or dry-blended with the additive prior to being mixed into the solution.
  • the additive may be at least one of a sugar, a plasticizer (e.g., polyethylene glycol, propyleneglycol, glycerol and sorbitol), or a crosslinking agent.
  • a plasticizer e.g., polyethylene glycol, propyleneglycol, glycerol and sorbitol
  • the sugar additive may be a sugar-ol, a poly-ol, or a hygroscopic polymer (e.g., polyethylene glycol).
  • the crosslinking agent may be photoreactive.
  • the crosslinking agent may be, for example, one or more of horseradish peroxidase, lysyl oxidase, disuccinimidyl suberate, disuccinimidyl glutarate, N-hydroxysuccinimide ester, or an aryl azide.
  • the additive may include one or more of a metal, or an enzyme,.
  • the metal may include one or more of an alkali metal, an alkaline earth metal, or a transition metal.
  • the additive may be an enzyme (i.e., an RNase or a DNase), a fatty acid, a sugar (e.g., an alcohol sugar), or a mineral.
  • the enzyme may include erepsin maltase, lactase, sucrase, disaccharidases, lingual lipase, lysozymes, salivary amylase, pepsin, gastric lipase, other lipases, hydrochloric acids, mucins, gastrins, trypsinogen, carboxypeptidase, elastases, papain, and the like.
  • the additive may be at least one of a coloring agent, a chelator, a ligand, an antimicrobial (e.g.,chitosan, zinc oxide and titanium oxide nanoparticles, silver, active carbon), a filler, a scent, a bio-based sensor (e.g., colorimetric sensor), a plasticizer, an ultraviolet resistant compound (e.g., titania, boron nitride, and zinc oxide), a foaming agent, and/or a flavor.
  • the additive and the silk protein form a composite that has improved properties (e.g., increased strength and stiffness) than silk protein alone.
  • the composite is a bio-nanocomposite.
  • the additive further serves as a CO2 scavenger/emitter, oxygen scavenger, ethylene scavenger, aroma emitter/odor absorber, time-temperature sensor, ripeness indicator, biosensor, and/or for sustained release of antioxidants during storage.
  • the coloring agent may be allura red, Ponceau 3R, amaranth, erythrosine, indigotine, Light Green SF, Naphthol yellow, Orange 1 , quinoline yellow, tartrazine, an E1 suit (e.g., E100, E161 b, etc.), an anthocyanin, a betacyanin, a carotenoid, or a phenolic.
  • the chelator may be ethylenediaminetetraacetic acid (EDTA), transferrin, or desferrixoxamine.
  • the antimicrobial may be acetic acid, benzoic acid, natamycin, nisin, nitrate, nitrite, propionic acid, sorbic acid, sulfite, or sulfur dioxide.
  • the filler may be cellulose.
  • the additive may be at least one of a marine oil, prebiotic, probiotic, encapsulated vitamin, phytochemical, bioavailable flavonoid, vitamin, a nutrient, an antioxidant, and a protein or a natural or synthetic amino acid.
  • a nutrient may be defined as a mineral, protein, carbohydrate, fat, Q10, glutathione, lithium, probiotic, glycine, DHA, flavonoid, or others.
  • An antioxidant may include vitamins C and E, selenium, carotenoids, thiols, catalase, superoxide dismutase, uric acid, and ubiquinol.
  • the protein comprises wheat gluten, corn zein, soy protein, pea protein, whey protein, casein, egg white, keratin, collagen, gelatin, caseinates, or a myofibrillar protein.
  • the additive may be at least one of a green tea extract, a rosemary extract, a phenolic antioxidant, catechin, acerola, tocopherol, chamomile extract, malphigia emarginata, camellia sinensis, epicatechin, epigallocatechin, gallochatechin, epigallocatechin gallates, vitamin A, vitamin E, and/or vitamin C.
  • the additive is an essential oil.
  • the additive comprises clay nanoparticles.
  • the additive is silver nanoparticles.
  • the additive may be mixed with an accelerant or an excipient.
  • the additive may be mixed with polyethylene glycol or xylitol.
  • the additive may be emulsified with the accelerant or excipient and mixed into a silk fibroin solution.
  • the silk may be applied to or mixed with any substrate.
  • the substrate is a biodegradable material.
  • the substrate is bio-based (biodegradable or non-degradable).
  • the substrate is a paper.
  • the substrate is a fiber (e.g., paper fiber).
  • the substrate comprises another protein (e.g., zein, gluten, whey protein, soy protein and caseinates).
  • the substrate is cardboard.
  • the substrate is a metal, paper, glass, or plastic (e.g., rigid, flexible, bioplastics).
  • the metal is aluminum, tin, or steel (tin-coated steel, or tin-free steel).
  • the paper e.g., corrugated boxes, milk cartoons, folding cartons, paper plates and cups, bags and sacks, wrapping paper
  • the paper is Kraft paper, sulphite paper, greaseproof paper, glassine, or parchment paper.
  • the substrate is paperboard (e.g., white board, solid board, chipboard, and fibreboard).
  • the paper comprises a wax.
  • the substrate is or comprises a wax.
  • the wax is natural (e.g., bees wax, soywax or candelilla wax).
  • the wax is petroleum-based (e.g., paraffin).
  • the substrate is a paper laminate.
  • the substrate is glass.
  • the substrate is plastic.
  • the plastic is thermoset plastic.
  • the substrate is thermoplastic.
  • the plastic comprises PP, LDPE, LLDPE, and/or PET.
  • the substrate comprises polyolefins (e.g., polyethylene and polypropylene) and/or polyester (e.g., polyethylene terephthalate).
  • the substrate is a polyester-polyethylene laminate.
  • the substrate is a bio-based polymer.
  • the substrate is a bio-based polymer selected from (i) polymers obtained directly from biomass including proteins (e.g., zein, gluten, whey protein, soy protein and caseinates) and polysaccharides (e.g., cellulose, starch, and chitosan); (ii) synthetic polymers from biomass derived or oil based monomers including polyactic acid (PLA), ethylene-vinyl alcohol (EVOH), polyvinyl alcohol (PVA) and polycaprolactones (PCL); and (iii) polymers developed by genetically modified or natural microorganisms such as bacterial cellulose or polyhydroxyalcanoates (PHAs).
  • PHA polyactic acid
  • EVOH ethylene-vinyl alcohol
  • PVA polyvinyl alcohol
  • PCL polycaprolactones
  • PHAs polymers developed by genetically modified or natural microorganisms such as bacterial cellulose or polyhydroxyalcanoates
  • the biodegradable material comprises starch, cellulose, cellulose nanocrystals and cellulose based polymers (polysaccharides) (e.g., cellulose acetate, and cellulose with lignin), chitosan, protein, Polyhydroxyalkanoates (PHA), polyhydroxybuterate (PHB), and a copolymer of PHB and valeric acid (RHBL/), bacterial cellulose, polyvinyl alcohol, polylactide, polyglycolide, Poly(e-caprolactone) (PCL), Poly(butylene succinate) (PBS), Poly(trimethylene terephthalate) (PTT), and/or Poly(butylene adipate-co-terephthalate) (PBAT).
  • the substrate is polylactic acid.
  • the substrate is stretch film, bundling film, or shrink film.
  • the silk is used in active packaging.
  • the silk protein may be used to coat a substrate.
  • the substrate is a packaging substrate.
  • the coating of a packaging substrate with silk improves barrier properties while maintaining recyclability or compostability in both primary and secondary packaging applications.
  • the composting degradation rate of the material stored or held within the packaging such as a food composition (e.g., non-perishable foods, fresh foods, and other perishable food products, and the like), may be controlled based on crystallinity, molecular weight, and/or porosity of the silk used to create a film or coating on the packaging.
  • Silk is not likely to impede paper repulping.
  • General paper repulping chemicals e.g., sodium hydroxide
  • Silk fibroin may be manufactured with particular molecular weights and crystallinity ranges to be readily compostable and naturally degraded by proteolytic enzymes found in, for example, animals, plants, fungi, and bacteria.
  • the rate of degradation may be controlled based on intrinsic characteristics to the silk fibroin itself, including but not limited to crystallinity, molecular weight, and porosity.
  • a silk coating on that same substrate would be similarly compostable.
  • a silk coated substrate may require different degradation methods or different degradation rates to fully compost.
  • the tunability e.g.
  • the silk fibroin may have a percent crystallinity in the range of about 5% to about 95%, or from about 10% to about 90%, or from about 20% to about 80%, or from about 20% to about 70%, or from about 20% to about 60%, or from about 20% to about 50%, or from about 20% to about 40%, or from about 25% to about 80%, or from about 25% to about 70%, or from about 25% to about 60%, or from about 25% to about 50%, or from about 25% to about 40%, or from about 30% to about 80%, or from about 30% to about 70%, or from about 30% to about 60%, or from about 30% to about 50%, or from about 30% to about 40%, or from about 40% to about 80%, or from about 40% to about 70%, or from about 40% to about 60%, or from about 40% to about 50%.
  • the chemicals used to break down paper materials and repulp to create new material are similar to the chemicals used to break down silk fibroin, which is manufactured to be readily compostable.
  • sodium hydroxide and other basic materials will degrade such silk fibroin at a similar rate and method to that of conventionally repulped paper materials.
  • a silk coated paper material would require additional steps or a significantly altered process to achieve the same repulping efficiency as with the same uncoated paper material.
  • the silk may be applied to a substrate by any method.
  • the silk is applied to the substrate by lamination, infusion (e.g., infusion of silk into foams, injection molds, paper pulp, or any other material used to make packaging), to fibrous structures (e.g., applying silk to material prior to weaving it into a fabric or to cellulose), impregnation (e.g. submersion), and/or coating (e.g., airbrush, doctor blade, dip coating, surface coating).
  • the silk is applied to a substrate by roller, gravure coating, comma rod, air knife, spray coating, curtain coating, or slot coating.
  • the silk is deposited onto a substrate and then dried via, for example, air-drying, freeze-drying, vacuum drying, or heat-drying.
  • the silk solution may be deposited onto a substrate via spray-coating.
  • the substrate may be silicone and one may peel off the silk film from a rubberized material.
  • the silk solution may also be used to make free-standing silk films. In this example, the silk solution is left to dry until only the silk film remains.
  • the free-standing silk film may be applied as a coating, sealed around an object to create a package, used as a film insert to packaging, combined with an adhesive to adhere to packaging.
  • the solution may be deposited onto a substrate via dip-coating.
  • the silk may be applied by electrospinning.
  • the substrate may undergo pre-treatment, by for example being exposed to a basic solution and then dried prior to application of the silk solution.
  • a pre-treatment could include adding a binder and/or adhesive to the substrate to improve the abrasion resistance or adhesion of the silk solution.
  • the surface of the substrate could be roughened by mechanical means to improve adhesion of the silk solution.
  • the pre-treatment may include treating the substrate with an oxidizing agent (e.g. acid) to tune the surface energy of the substrate to improve the wetting characteristics of the silk solution and improve adhesion of the silk.
  • the substrate could be treated with low temperature plasma to improve the wetting characteristics of the silk solution and improve adhesion of the silk solution.
  • the pre-treatment could include coating the substrate with a pore filler or surface roughness modifier (e.g., nanofibrillated cellulose) to tune the surface texture of the substrate to improve the adhesion of the silk solution.
  • the silk coating applied to a substrate may undergo post treatment to improve the properties of the silk coating, including treatment with alcohol (e.g., methanol, ethanol, isopropanol).
  • the post-treatment could include ultraviolet exposure to cross-link the silk coating or heat treatment to activate a foaming agent in the silk coating.
  • the silk may or may not be annealed after or before deposition, including by water annealing.
  • the substrate may include multiple layers of silk.
  • the substrate may be sprayed with silk solution, dried, and then sprayed once more. This may happen any number of times to add thickness and additional layers.
  • the substrate may comprise multiple layers, with each layer serving a function.
  • the substrate may be coated with silk solution.
  • the silk solution-coated substrate may be itself coated by another coating that is hydrophobic or water-tight such that water may not permeate the outer layer and reach the inner silk layer.
  • multiple different substrates may be coated with silk and combined to form a single substrate with alternating layers of silk coating and substrate.
  • a paper product could have alternating layers of paper and silk coating that form a single product.
  • a tablet-coating may be utilized, where the silk is coated while in an industrially-relevant drum. Tablet coating may additionally be utilized, as well as film-coating.
  • the film may be heated in order to bind to papers or to be used to envelope certain foods or materials.
  • a combination of the processes and methods disclosed above could be used to obtain the desired coating performance on any suitable substrate.
  • free-standing silk films may be created from the silk.
  • a thin layer of silk solution e.g., a silk fibroin and solvent
  • a mold e.g., rubber, silicone, polyethylene.
  • the silk coating or silk film may be of different thicknesses depending on the desired application or method used to create it.
  • the silk coating or silk film may be uniform in thickness.
  • the silk coating or silk film may not have a uniform thickness.
  • the silk coating may be thinner in some areas due to natural variances caused by the method used to apply the coating (e.g., a spray coating may vary in thickness due to variances during the application process such as spraying one area slightly longer than others resulting in different coating thickness).
  • the thickness may be varied on purpose to create specific barrier properties.
  • the thickness may range from about 10 nm to about 1 mm, from about 10 nm to about 50nm, from about 50 nm to about 100 nm, from about 100 nm to about 200 nm, from about 100 nm to about 100 pm, from about 200 nm to about 300 nm, from about 300 nm to about 500 nm, from about 500 nm to about 1 pm, from about 1 pm to about 5 pm, from about 5 pm to about 10 pm, from about 10 pm to about 15 pm, from about 10 pm to about 20 pm, from about 10 pm to about 25 pm, from about 10 pm to about 50 pm, from about 10 pm to about 100 pm, from about 15 pm to about 25 m, from about 15 m to about 35 pm, from about 15 pm to about 50 pm, from about 20 pm to about 40 pm, from about 20 pm to about 50 pm, from about 25 pm to about 35 pm, from about 25 pm to about 50 pm, from about 25 pm to about 100 pm, from about 30 pm to about 50 pm, from about 30
  • the thickness of the silk coating or silk film may have a thickness less than 1 mm. In an embodiment, the thickness of the silk coating or silk film may have a thickness less than 500 pm. In an embodiment, the thickness of the silk coating or silk film may have a thickness less than 300 pm. In an embodiment, the thickness of the silk coating or silk film may have a thickness less than 200 pm. In an embodiment, the thickness of the silk coating or silk film may have a thickness less than 150 pm. In an embodiment, the thickness of the silk coating or silk film may have a thickness less than 100 pm. In an embodiment, the thickness of the silk coating or silk film may have a thickness less than 80 pm. In an embodiment, the thickness of the silk coating or silk film may have a thickness less than 70 pm.
  • the thickness of the silk coating or silk film may have a thickness less than 60 pm. In an embodiment, the thickness of the silk coating or silk film may have a thickness less than 50 pm. In an embodiment, the thickness of the silk coating or silk film may have a thickness less than 40 pm. In an embodiment, the thickness of the silk coating or silk film may have a thickness less than 30 pm. In an embodiment, the thickness of the silk coating or silk film may have a thickness less than 25 pm. In an embodiment, the thickness of the silk coating or silk film may have a thickness less than 20 pm. In an embodiment, the thickness of the silk coating or silk film may have a thickness less than 15 pm. In an embodiment, the thickness of the silk coating or silk film may have a thickness less than 10 pm.
  • the thickness of the silk coating or silk film may have a thickness less than 1 pm. In an embodiment, the thickness of the silk coating or silk film may have a thickness less than 500 nm. In an embodiment, the thickness of the silk coating or silk film may have a thickness less than 100 nm.
  • a substrate may be coated in its entirety or only partially.
  • the substrate may only be coated on the inside surfaces of the wrapper.
  • one surface of a substrate may be coated, e.g., a box may have one surface coated, while the other surfaces may not be coated.
  • the package may only be coated over a portion of a surface of a substrate, for example a surface may only be partially coated such that half of one surface receives a coating.
  • the substrate may have about 100% of its total surface area coated, or about 80% or more of its total surface area coated, or about 60% or more of its total surface area coated, or about 50% or more of its total surface area coated, or about 40% or more of its total surface area coated, or about 30% or more of its total surface area coated, or about 20% or more of its total surface area coated, or about 10% or more of its total surface area coated.
  • between about 80% to about 100% of the total surface area of a substrate may be coated, or between about 60% to about 80% of the total surface area of a substrate may be coated, or between about 50% to about 80% of the total surface area of a substrate may be coated, or between about 40% to about 60% of the total surface area of a substrate may be coated, or between about 20% to about 40% of the total surface area of a substrate may be coated, or between about 1 % to about 20% of the total surface area of a substrate may be coated.
  • the mechanical properties of the silk films and coatings may also be tunable by heat treatment, ultraviolet exposure, and gamma radiation. Heated silk films may have higher tensile strength and increased rigidity.
  • the silk films and silk-coated materials have advantageous oxygen Transmission Rate (OTR), Water Vapour Transmission Rate (WVTR), water droplet barrier formation, grease barrier formation, improved sealing properties (both as a thermal insulator and air seal), and/or bacterial barrier formation.
  • OTR oxygen Transmission Rate
  • WVTR Water Vapour Transmission Rate
  • the silk films and silk-coated materials may modify the surface of the material coated, by for example, improving printability of the surface (e.g., increasing adherence of ink or other coloring agents to substrate), modifying friction of the surface by increasing grip or increasing smoothness.
  • the silk films and silk-coated materials may also permit surface modifications (e.g., embossing, debossing, stamping) to the coating.
  • the silk films and silk-coated materials may also impact the mechanical stability when applied, by altering the wet burst strength, tensile resistance, tensile strength, compressive strength, and/or folding stability.
  • silk when applied to a substrate may decrease the OTR of the substrate by about 5% or more, or by about 10% or more, or by about 20% or more, or by about 30% or more, or by about 40% or more, or by about 50% or more, or by about 60% or more, or by about 70% or more, or by about 80% or more, or by about 90% or more, or by about 95% or more, or by about 99% or more.
  • silk applied to a substrate may decrease the WVTR of the substrate by about 5% or more, or by about 10% or more, or by about 20% or more, or by about 30% or more, or by about 40% or more, or by about 50% or more, or by about 60% or more, or by about 70% or more, or by about 80% or more, or by about 90% or more, or by about 95% or more, or by about 99% or more.
  • the OTR and WVTR of the substrate may both decrease after application of silk to a substrate.
  • the silk films or silk-coated materials may be optimized as necessary by changing various properties of the silk, the coating method, and the treatment of the coating to arrive at the desired performance for a specific substrate.
  • the packaging material itself may also be taken into account when optimizing the silk coating.
  • substrates have different characteristics, including surface roughness, porosity, chemical composition, structure, construction method, components. These different characteristics will likely impact what silk is suitable and what application method is ideal. For example, if packaging holds a product that is sensitive to water, the silk coating applied to the packaging may be optimized to decrease the WVTR of the packaging. Similarly, if the product held in the package degrades more quickly if exposed to airflow, the silk coating applied to the packaging may be optimized to decrease the OTR of the packaging.
  • lamination may be suitable for a substrate with a rough surface because it ensures a more uniform layer of silk compared to other application methods.
  • a porous substrate such as paper, may benefit from submersion to increase the transparency of the paper if that is valued in certain circumstances, such as in a wrapper for a food item. This tunablity enables customization for specific applications for each substrate, and also the products held within the substrate.
  • the silk films and silk-coated packaging materials of the disclosure may be used for any purpose.
  • the silk-containing packaging materials may be used for food compositions, e.g., non-perishable foods, fresh foods, and other perishable food products.
  • the silk-containing packaging materials may be used for packaging non-perishable food products.
  • the silk- containing packaging materials may be used for frozen foods, processed foods, beverages, candy, chocolate, or dried foods.
  • the packaging materials may be used to package fruits, juices; milk, cheese, and other dairy products; soft drinks, beer, wine, and other beverages; vegetables, snacks foods, bakery goods, canned foods, cereals, candy, pet foods, meat, fish.
  • They may be used for storage boxes, wrapping paper, wrapping films and other films, lids, caps, reusable containers, pouches, bags, cans, bottles, jars, take-out boxes, jars, corrugated boxes, milk cartoons, folding cartons, paper plates and cups, bags and sacks, wrapping paper, and the like.
  • Paper - food grade may be woven, unwoven, cardboard, or other materials
  • the paper may also be pre-treated, for example, with a highly basic solution and then left to fully dry prior to applying the silk solution.
  • the basic solutions could include sericin wastewater created while processing the silk fibroin, where the sericin is removed, high molecular weight silk only solution, and/or water.
  • the application of the pre-treatment solution may include soaking, dipping, spraying, or misting.
  • the paper may also undergo post-treatment to alter the performance of the paper.
  • the paper may be treated with alcohol (e.g., methanol, ethanol, isopropanol), low pH solutions, acid, and/or by water annealing. This treatment induces additional crystallinity formation and improves the barrier properties of the film, such as by making the coating less soluble.
  • alcohol e.g., methanol, ethanol, isopropanol
  • FIG. 1 shows an example of transparent (also known as translucent) paper. This paper may be prepared as disclosed above to create a product that is permeated with silk.
  • FIG. 2 shows another view of transparent paper, highlighting a section of increased thickness to better illustrate the transparency achieved using the silk solution to form a coating.
  • FIGS. 3a and 3b show the same piece of transparent paper.
  • FIG. 3a shows the transparent paper sitting on a tabletop
  • FIG. 3b shows the flexibility of the same transparent paper, as the paper may bend even though the silk has permeated the paper.
  • the flexibility of the transparent paper may be improved by including additives in the silk solution, including plasticizers.
  • FIG. 3b shows a piece of paper that included plasticizers in the silk solution.
  • FIGS. 4a-4b and 5a-5b show different methods for applying a silk solution to a piece of paper to create a silk coating.
  • FIG. 4a shows a spray coating that was applied using an airbrush.
  • the airbrush sprays the surface of the substrate, in this case paper, with a silk solution, where the solution is prepared with the same ratios of silk and water as disclosed above.
  • the substrate may be placed on a flat surface and sprayed or held in place by any suitable means (e.g., alligator clips, mounting putty, and binder clips) during spraying.
  • an airbrush applies atomized particles under high pressure, for example approximately 30 psi.
  • Other possible embodiments include a low pressure spray application, that applies larger droplets onto the paper.
  • the silk solution has just been applied to the circle on the right, while it has not been applied to the circle on the left.
  • the paper is wet after application of the silk solution, but once dry, as shown in FIG. 4b, the coating is almost imperceptible. Additional layers of silk could be added by spray coating the paper as many times as desired.
  • FIG. 5a shows a doctor blade that may be used to apply silk solution to a substrate, which is paper in this example.
  • a substrate which is paper in this example.
  • the same potential ratio of silk to water as disclosed above in Example 2 may be utilized.
  • the solution is distributed across the substrate using the doctor blade and left to dry, where a coating may be created.
  • FIG. 5b shows the solution after it is spread across the paper by the doctor blade but prior to drying.
  • a free-standing silk film may be created with different methods.
  • Fig. 6 shows the result of one potential method, where a free-standing silk film is attached to a frame, in this case an embroidery hoop, prior to separation from the frame.
  • a removable material such as a polyethylene film
  • a silk solution with the percent of silk and water disclosed above, is then poured onto the removable material, and held in place by the frame.
  • the silk solution is left to dry (typically between 12-48 hours), until all the water has evaporated, leaving only a silk film on the removeable layer.
  • the removable layer and free-standing silk film are separated, leaving a free-standing silk film that may or may not be attached to a frame. If the free-standing silk film is attached to the frame they may also be separated to create a free-standing silk film.
  • Various methods to increase airflow over the free-standing silk film may be used to decrease the drying time, including using fans.
  • the free-standing silk film may also receive post-treatment, by for example, application of alcohol, low pH solutions, acid, and/or water annealing, as disclosed in other examples.
  • the silk solution can be placed in different forms or molds, for example, those made of silicone or other materials that inhibit or decrease binding of the free-standing silk film to the form or mold.
  • the free-standing silk film is then removed from the form or mold. In this way, any shape may be created.
  • Fig. 7 shows an example of free-standing silk used to encapsulate a food composition in a package made entirely of free-standing silk.
  • two pieces of free-standing silk are placed on either side of a food composition and then crimped or joined together at their edges to form a package surrounding the food composition.
  • the crimping or joining may be accomplished by any suitable method.
  • FIG. 8 shows silk laminated paper after lamination has been completed.
  • This first step to create silk laminated paper is creating a free-standing silk film, as discussed in Example 4 above. Once the free-standing silk film is created, it is placed on paper and then heat and pressure are applied to both the paper and the free-standing silk film to create a laminated layer of silk on the paper. This may be accomplished using any conventional lamination device or heat sources that can apply pressure, like a t-shirt press or iron.
  • the paper may also be pre-treated by applying water prior to lamination. Multiple layers could be placed on the paper using the same method after the initial layer is added, namely adding additional free-standing silk film layers, and laminating them. Similarly to Example 2, pre-treatment and post-treatment could be utilized to obtain the desired coating performance.
  • FIG. 9 shows a Cobb test result.
  • the test measures the absorption and permeability of water through layers of substrates by placing a set amount of water on a substrate for a predetermined amount of time.
  • uncoated paper, and paper that was spray coated with different amounts of silk solution were tested.
  • the results indicate that increased mass loading of silk (increased amounts of silk per cm 2 ) increases the water resistance of the paper since less wetness was observed in the second layer of paper as the silk mass loading increased.
  • FIG. 10 shows a plot of the results of the Cobb test in FIG. 9.
  • the graph shows the amount of water absorbed by the paper via weight gain, with decreased water absorption when mass loading of silk increased.
  • the mass gained in uncoated paper is roughly 27%, while the amount of mass gained by the silk coated samples is approximately 18% (X mg/cm 2 ), 12% (2X mg/cm 2 ), and 9% (5X mg/cm 2 ).
  • FIG. 11 shows the results of a second Cobb test, where different amounts of silk solution of different molecular weights are applied to paper.
  • This test shows that higher molecular weight (M ) silk solutions (e.g., a weight average molecular weight of 170-460 kDa) permit less water to permeate lower layers of paper than lower molecular weight silk (M ) solutions (e.g., a weight average molecular weight of 10-200 kDa), and that thicker layers of the same molecular weight silk forms a barrier with decreased water permeation to lower layers of paper.
  • M molecular weight
  • FIG. 12 shows the results of a fourth Cobb test as a graph, where different amounts of silk solution of different molecular weights are applied to paper.
  • higher molecular weight (Mw) silk solution forms a stronger barrier limiting water absorption by the paper.
  • increased mass loading of silk also decreases water absorption.
  • substrates coated with silk and free-standing silk films exhibit decreased OTR compared to an uncoated substrate.
  • an uncoated substrate was compared to (1 ) the same substrate submerged once in a silk solution, (2) the same substrate submerged twice in a silk solution, and (3) a free-standing silk film.
  • the OTR of each of these four was measured.
  • the substrate showed dramatic improvements in OTR after submersion, with one submersion reducing OTR by around 99%.
  • the second submersion reduced the OTR even further, by around 99% more compared to the single submersion sample.
  • the free-standing silk film exhibited very similar OTR to the substrate that was submerged twice.
  • FIGs. 13 and 14 show a packaging product with a silk-based window to permit a view of the inside of the packaging product while forming a barrier between the interior of the packaging and the exterior.
  • the packaging product (A) is a bag with a window (B) in the front.
  • a free-standing silk film is incorporated into the packaging over the window so that the interior of the bag is viewable.
  • a translucent or semi-translucent piece of paper formed using silk is incorporated into the packaging over the window. Any suitable means to secure the window to the packaging product could be utilized, including for example, adhesives, staples, pressing, heat treatment.
  • FIG. 14 shows another packaging product that is a box.
  • the box (A) in FIG. 14 has a window (B) in the top of the box.
  • the window could comprise a free-standing silk film or a translucent or semi-translucent piece of paper formed using silk to permit a view into the box while still maintaining a barrier to the interior of the box.

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  • Engineering & Computer Science (AREA)
  • Ceramic Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Materials Engineering (AREA)
  • Wood Science & Technology (AREA)
  • Organic Chemistry (AREA)
  • Peptides Or Proteins (AREA)

Abstract

Selon des aspects, la présente divulgation est relative à des compositions et à des procédés de préparation de films de soie destinés à être utilisés dans un emballage alimentaire. Des compositions de la présente divulgation données à titre d'exemple comprennent des films de soie et des revêtements d'emballage visant à remplacer un emballage alimentaire traditionnel, tel qu'un emballage en plastique à usage unique, et/ou à prolonger la durée de conservation d'aliments. Les revêtements naturels de soie à base biologique de la présente divulgation peuvent être inodores, peu coûteux, comestibles, compostables, issus d'une source renouvelable, amovibles de l'emballage à des fins de recyclage et sont biodégradables. Selon certains modes de réalisation, les films de soie et les revêtements d'emballage peuvent prolonger la durée de conservation, améliorer ou maintenir la qualité et la sécurité, et/ou fournir une indication de la fraîcheur de produits alimentaires et réguler cette dernière.
PCT/US2021/027333 2021-04-14 2021-04-14 Applications d'emballage de soie WO2022220827A1 (fr)

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CN116858827A (zh) * 2023-07-25 2023-10-10 河北科技大学 一种冷库用肉制品新鲜度荧光指示标签纸及其制备方法

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US20110014287A1 (en) * 2009-04-20 2011-01-20 Altman Gregory H Silk Fibroin Hydrogels and Uses Thereof
US20150202304A1 (en) * 2012-07-13 2015-07-23 Tufts University Encapsulation of immiscible phases in silk fibroin biomaterials
US20160222579A1 (en) * 2014-12-02 2016-08-04 Silk Therapeutics, Inc. Silk Performance Apparel and Products and Methods of Preparing the Same
WO2017177281A1 (fr) * 2016-04-14 2017-10-19 Ear Science Institute Australia Membranes améliorées composées de polyuréthane biocompatible et de fibroïne
US20190343137A1 (en) * 2014-03-07 2019-11-14 Tufts University Biopolymer-Based Preservation of Perishable Products

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20110014287A1 (en) * 2009-04-20 2011-01-20 Altman Gregory H Silk Fibroin Hydrogels and Uses Thereof
US20150202304A1 (en) * 2012-07-13 2015-07-23 Tufts University Encapsulation of immiscible phases in silk fibroin biomaterials
US20190343137A1 (en) * 2014-03-07 2019-11-14 Tufts University Biopolymer-Based Preservation of Perishable Products
US20160222579A1 (en) * 2014-12-02 2016-08-04 Silk Therapeutics, Inc. Silk Performance Apparel and Products and Methods of Preparing the Same
WO2017177281A1 (fr) * 2016-04-14 2017-10-19 Ear Science Institute Australia Membranes améliorées composées de polyuréthane biocompatible et de fibroïne

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116858827A (zh) * 2023-07-25 2023-10-10 河北科技大学 一种冷库用肉制品新鲜度荧光指示标签纸及其制备方法
CN116858827B (zh) * 2023-07-25 2023-12-19 河北科技大学 一种冷库用肉制品新鲜度荧光指示标签纸及其制备方法

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