Classifications

• • 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
  • C08J9/0061—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof characterized by the use of several polymeric components
• • 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
  • C08J9/143—Halogen containing compounds
  • C08J9/144—Halogen containing compounds containing carbon, halogen and hydrogen only
  • C08J9/145—Halogen containing compounds containing carbon, halogen and hydrogen only only chlorine as halogen atoms
• • 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
  • C08J9/149—Mixtures of blowing agents covered by more than one of the groups C08J9/141 - C08J9/143
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L97/00—Compositions of lignin-containing materials
• • 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
  • C08J2203/14—Saturated hydrocarbons, e.g. butane; Unspecified hydrocarbons
  • C08J2203/142—Halogenated saturated hydrocarbons, e.g. H3C-CF3
• • 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
  • C08J2203/182—Binary blends of expanding agents of physical blowing agents, e.g. acetone and butane
• • 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
  • C08J2205/052—Closed cells, i.e. more than 50% of the pores are closed
• • 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
  • C08J2205/10—Rigid foams
• • 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
  • C08J2361/00—Characterised by the use of condensation polymers of aldehydes or ketones; Derivatives of such polymers
  • C08J2361/04—Condensation polymers of aldehydes or ketones with phenols only
  • C08J2361/06—Condensation polymers of aldehydes or ketones with phenols only of aldehydes with phenols
  • C08J2361/08—Condensation polymers of aldehydes or ketones with phenols only of aldehydes with phenols with monohydric phenols
  • C08J2361/10—Phenol-formaldehyde condensates
• • 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
  • C08J2397/00—Characterised by the use of lignin-containing materials

Definitions

• This disclosure relates in general to condensed tannin-based foams and in particular formaldehyde-free condensed tannin-based foams and mixed tannin-phenolic foams.
• Proanthocyanidins also known as condensed tannins, are a class of polyphenolic compounds found in several plant species and are oligomers and polymers of polyhydroxy-flavan-3-ol monomer units and are associated with carbohydrates and traces of amino and imino-acids.
• Condensed tannins are the second most abundant family of natural phenolic compounds, after lignin, found in virtually all families of plants.
• the main commercial sources of condensed tannin extracts are from Quebracho (Schinopsis balansae) heartwood and Mimosa or black wattle (Acacia mearnsii) bark.
• the phenolic nature of condensed tannin imparts the ability to condense with formaldehyde and other aldehydes to form crosslinked networks (thermoset resins and foams). Because
• formaldehyde-based resins are by far the most common raw materials for the preparation of adhesive formulations for wood-based panels, tannins have for a long time been seen as a potential substitute for phenol in the making of such resins.
• the tannin content of the bark varies within a single tree, age and thickness of bark, soil conditions, rainfall and other environmental factors. Also, the constituent components present in commercially available condensed tannins vary from extraction method (time, temperature and solvent) and undisclosed minor chemicals added after extraction to maintain the quality of the tannin extract.
• condensed tannin- based foam comprising:
• the formaldehyde-free polymeric phase comprises an acid catalyzed tannin-based resin derived from a surface- active condensed tannin, a formaldehyde-free tannin- reactive monomer, a saturated or an unsaturated organic anhydride, an ethoxylated castor oil, and an optional polyamine and/or plasticizer,
• the formaldehyde-free tannin-reactive monomer comprises furfuryl alcohol, furfural, glyoxal, acetaldehyde, glutaraldehyde, 5-hydroxymethylfurfural, acrolein, levulinate esters, sugars, 2,5-furandicarboxylic aldehyde, difurfural (DFF), glycerol, sorbitol, or mixtures thereof, - wherein the saturated and unsaturated organic anhydride comprises at least one of maleic anhydride, acetic
• polyamine comprises at least one of urea and melamine
• blowing agents disposed in at least a portion of the plurality of closed-cells, wherein at least one of the blowing agents is an azeotrope or an azeotrope-like mixture of isopentane and one other blowing agent selected from the group consisting of isopropyl chloride, 1 ,1 ,1 ,4,4,4-hexafluoro-2-butene and 1 -chloro-3,3,3,- trifluoropropene; and
• the condensed tannin-based foam has an aged thermal conductivity of less than 25 mW/m-K, measured at 25 °C.
• a formaldehyde-free tannin-reactive monomer comprising furfuryl alcohol, furfural, glyoxal, acetaldehyde, glutaraldehyde, 5-hydroxymethylfurfural, acrolein, levulinate esters, sugars, 2,5-furandicarboxylic aldehyde, difurfural (DFF), glycerol, sorbitol, or mixtures thereof, and
• DFF difurfural
• composition at a temperature in the range of 50-100 °C to form a foam comprising a formaldehyde-free polymeric phase defining a plurality of cells, and wherein one or more blowing agents is disposed in at least a portion of the plurality of cells.
• step (b) adding 10-90% by weight of a phenolic-resole prepolymer to the tannin solution of step (b) to form a tannin-phenolic resole mixture,
• the phenolic-resole prepolymer is derived from a phenol and a phenol-reactive monomer and further comprises urea
• the phenol-reactive monomer comprises at least one of formaldehyde, paraformaldehyde, furfuryl alcohol, furfural, glyoxal, acetaldehyde, glutaraldehyde, 5- hydroxymethylfurfural, levulinate esters, sugars, 2,5- furandicarboxylic aldehyde, difurfural (DFF) and sorbitol, and d) adding at least one blowing agent to the tannin-phenolic resole mixture;
• tannin-phenolic resole mixture to form a tannin-phenolic resole foamable composition
• composition at a temperature in the range of 50-100 °C to form a mixed tannin-phenolic foam comprising a polymeric phase defining a plurality of cells, and wherein one or more blowing agents is disposed in at least a portion of the plurality of cells.
• Figure 1 shows the effect of maleic anhydride on moisture absorption by a condensed tannin-based foam.
• Figures 2A and 2B show GC-MS headspace spectra of commercial condensed tannin extracts from two different geographical regions: as- received Tannin-A and as-received Tannin-F respectively.
• Figures 3A, 3B, and 3C show GC-MS headspace spectra of commercial condensed tannin extracts: as-received Tannin-F; volatile-free condensed tannin obtained by heating the as-received Tannin-F in air; and volatile- free condensed tannin obtained by heating the as-received Tannin-F in nitrogen respectively.
• surface-active condensed tannin refers to those bio-derived condensed tannins that when dissolved in 50 wt% of water has a surface tension of less than 53.0 mN/m, wherein the amount in weight% is based on the total weight of the tannin and water.
• volatile-free condensed tannin refers to a surface-active condensed tannin composition, that is substantially free of one or more volatile compounds, wherein the one or more volatile compounds has a boiling point of greater than 277 °C, as analyzed by GC- MS headspace method disclosed infra.
• the phrase “volatile-free condensed tannin” refers to a surface-active condensed tannin composition, that is substantially free of one or more volatile compounds, wherein the one or more volatile compounds has a boiling point of greater than 277 °C, as analyzed by GC- MS headspace method disclosed infra.
• condensed tannin composition substantially free of one or more volatile compounds refers to tannin compositions wherein the amount of individual volatile component having boiling points greater than 277 °C, as measured by GC-MS headspace spectrum disclosed infra, and expressed as peak area is less than 1 .0 x 10 "5 , or less than 0.7 x 10 "5 , or less than 0.5 x10 "5 .
• Figures 3B and 3C shows GC-MS headspace spectra of volatile-free condensed tannin obtained by heating the as-received Tannin-F in air and in nitrogen respectively.
• the volatile- free condensed tannin are substantially free of one or more volatile compounds having a boiling point of greater than 277 °C.
• the Figure 3A shows GC-MS headspace spectra of as-received
• Tannin-F comprising one or more volatile compounds having a boiling point of greater than 277 °C.
• surface-active condensed tannin is used interchangeably with “condensed tannin” and “tannin” and refers to bio- derived condensed tannins.
• biologically-derived is used
• bio-derived refers to chemical compounds including monomers and polymers, that are obtained from plants and contain major amount of renewable carbon, and minor amount of fossil fuel-based or petroleum-based carbon, wherein the minor amounts are chemicals could be residuals from extraction process or additives added for stabilization or other purposes.
• bio-based composition refers to compositions that contains at least 25% renewable carbon, and less than 75% fossil fuel based or petroleum based carbon.
• bio-derived tannins are vegetable-based, extracted from leaf, bud, seed, root, bark, trunk, nut shells, skins of fruits, and stem tissues of plants and trees.
• mimosa tannin refers to a tannin extracted from leaf, bud, seed, root, bark, trunk, or stem tissues of a mimosa tree.
• the condensed tannin may also be extracted from other plant resources, including, but not limited to bark such as wattle, mangrove, oak, eucalyptus, hemlock, pine, larch, and willow; woods such as quebracho, chestnut, oak and urunday, cutch and turkish; fruits such as myrobalans, valonia, divi-divi, tera, and algarrobilla; leaves such as sumac and gambier; and roots such as canaigre and palmetto.
• bark such as wattle, mangrove, oak, eucalyptus, hemlock, pine, larch, and willow
• woods such as quebracho, chestnut, oak and urunday, cutch and turkish
• fruits such as myrobalans, valonia, divi-divi, tera, and algarrobilla
• leaves such as sumac and gambier
• roots such as canaigre and
• the main commercial sources of condensed tannins are from Quebracho (Schinopsis balansae) heartwood, Mimosa (Acacia mearnsii, Acacia mollissima, Acacia mangium) bark and pine (Pinus radiate, Pinus pinaster) bark, Spruce (Picea abies) bark Pecan (Carya illinoensis) bark and
• Catechu (Acacia catechu) wood and bark.
• Condensed mimosa tannins are oligomers or polymers mostly composed of flavan-3-ols repeating units as shown in Scheme 1 , linked 4- 6 or 4-8 to each other, and smaller fractions of polysaccharides and simple sugars.
• the commercial condensed tannins in general are extracted from the bark chips using a counter-current flow principle in pressurized autoclaves.
• the resulting liquid extract is then concentrated by
• the spray-dried tannins can absorb 6-8 wt% water from the atmosphere, due to hydrophilic nature of the tannins.
• tannin-reactive monomer As used herein, the term “formaldehyde-free tannin-reactive monomer” is used interchangeably with the term “tannin-reactive monomer” and refers to those monomers that in the presence of an acid catalyst reacts with the A ring of the tannins at the free 5, 6 or 8 sites, as shown in Scheme 1 .
• the tannin-reactive monomer as disclosed herein excludes formaldehyde.
• polyamine refers to an organic compound having two or more amino groups. Suitable examples of polyamine include, but are not limited to urea, melamine, and hexamine.
• Formaldehyde-free polymeric phase means that the polymeric phase is formed without the use of formaldehyde as a monomer.
• phenol ic-resole prepolymer refers to a condensation product of phenol and phenol-reactive monomer, having reactive methylol groups and is generally prepared with a molar ratio of phenol-reactive monomer to phenol of > 1 in the presence of a basic catalyst.
• the phenol used to prepare phenolic-resole pre-polymer may be a substituted phenol or unsubstituted phenol.
• substituted phenol refers to a molecule containing a phenolic reactive site and can contain another substituent group or moiety.
• Exemplary phenols include, but are not limited to, unsubstituted phenol, ethyl phenol, p-tertbutyl phenol; ortho, meta, and para cresol; resorcinol; catechol;
• phenol-reactive monomer refers to any monomer that reacts with nucleophilic sites of the phenol.
• exemplary phenol-reactive monomer include, but is not limited to formaldehyde, paraformaldehyde, furfuryl alcohol, furfural, glyoxal, acetaldehyde, glutaraldehyde, 5-hydroxymethylfurfural, levulinate esters, sugars, 2,5- furandicarboxylic aldehyde, difurfural (DFF) and sorbitol.
• tannin-phenolic resole mixture refers to a composition obtained by mixing a phenolic-resole prepolymer with a tannin solution comprising a volatile-free condensed tannin dissolved in water and a tannin-reactive monomer.
• bio-based foam is used interchangeably with “bio-based closed-cell foam” and refers to foams that are derived from at least one monomer of the resin that is obtained from plants and the foam contains at least 25% renewable carbon, and less than 75% fossil fuel based or petroleum based carbon.
• blowing agent is used interchangeably with the term “foam expansion agent”.
• the blowing agent must be volatile and inert, and can be inorganic or organic.
• azeotrope-like is intended in its broad sense to include both compositions that are strictly azeotropic and compositions that behave like azeotropic mixtures. From fundamental principles, the thermodynamic state of a fluid is defined by pressure, temperature, liquid composition, and vapor composition.
• An azeotropic mixture is a system of two or more components in which the liquid composition and vapor composition are equal at the stated pressure and temperature. In practice, this means that the components of an azeotropic mixture are constant boiling and cannot be separated during a phase change.
• the azeotrope-like compositions of the present disclosure may include additional components that do not form new azeotrope-like systems, or additional components that are not in the first distillation cut.
• the first distillation cut is the first cut taken after the distillation column displays steady state operation under total reflux conditions.
• One way to determine whether the addition of a component forms a new azeotrope- like system so as to be outside of the present disclosure is to distill a sample of the composition with the component under conditions that would be expected to separate a non-azeotropic mixture into its separate components. If the mixture containing the additional component is non- azeotrope-like, the additional component will fractionate from the azeotrope-like components. If the mixture is azeotrope-like, some finite amount of a first distillation cut will be obtained that contains all of the mixture components that is constant boiling or behaves as a single substance.
• azeotrope-like compositions there is a range of compositions containing the same components in varying proportions that are azeotrope-like or constant boiling. All such compositions are intended to be covered by the terms "azeotrope-like" and "constant boiling".
• azeotrope-like and "constant boiling”.
• a and B represents a unique type of relationship, but with a variable composition depending on temperature and/or pressure. It follows that, for azeotrope-like compositions, there is a range of
• compositions containing the same components in varying proportions that are azeotrope-like are intended to be covered by the term azeotrope-like as used herein.
• ODP ozone depletion potential
• the global-warming potential (GWP) used herein is a relative measure of how much heat a greenhouse gas traps in the atmosphere. It compares the amount of heat trapped by a certain mass of the gas in question to the amount heat trapped by a similar mass of carbon dioxide, which is fixed at 1 for all time horizons (20 years, 100 years, and 500 years). For example, CFC-1 1 has GWP (100 years) of 4750. Hence, from the global warming perspective, a blowing agent should have zero ODP and as low GWP as possible.
• the term "open-cell” refers to individual cells that are ruptured or open or interconnected producing a porous "sponge” foam, where the gas (air) phase can move around from cell to cell.
• the term “closed-cell” refers to individual cells that are discrete, i.e. each closed-cell is enclosed by polymeric sidewalls that minimize the flow of a gas phase from cell to cell. It should be noted that the gas phase may be dissolved in the polymer phase besides being trapped inside the closed-cell.
• the gas composition of the closed-cell foam at the moment of manufacture does not necessarily correspond to the equilibrium gas composition after aging or sustained use. Thus, the gas in a closed-cell foam frequently exhibits compositional changes as the foam ages leading to such known phenomenon as increase in thermal conductivity or loss of insulation value.
• closed mold means partially closed mold where some gas may escape, or completely closed mold, where the system is sealed.
• a condensed tannin-based foam formed by foaming and curing a formaldehyde-free foamable composition at a temperature in the range of 50-100 °C, the formaldehyde-free foamable composition comprising a surface-active condensed tannin, a
• the as-formed condensed tannin-based foam comprises a formaldehyde-free polymeric phase defining a plurality of cells wherein the plurality of cells comprises a plurality of open cells and a plurality of closed cells.
• the as-formed condensed tannin-based foam also comprises one or more blowing agents disposed in at least a portion of the plurality of closed-cells, formed by the formaldehyde-free polymeric phase.
• the formaldehyde-free polymeric phase of the condensed tannin- based foam comprises an acid catalyzed tannin-based resin derived from a surface-active condensed tannin, a formaldehyde-free tannin-reactive monomer, a saturated or an unsaturated organic anhydride, an
• ethoxylated castor oil ethoxylated castor oil, and an optional polyamine and/or plasticizer.
• the surface-active condensed tannin of the present disclosure refers to those bio-derived tannins that when dissolved in 50 weight% of water has a surface tension of less than 53.0 mlM/m, wherein the amount in weight% is based on the total weight of the tannin and water.
• the surface-active condensed tannin is extracted from at least one of a mimosa tree, a quebracho tree, or a pine tree.
• the surface-active condensed tannin is a mimosa tannin extracted from plant Acacia mearnsii.
• the surface-active condensed tannin is a volatile-free condensed tannin, as disclosed hereinabove.
• Any suitable formaldehyde-free tannin-reactive monomer can be used, including, but not limited to furfuryl alcohol, furfural, glyoxal, acetaldehyde, glutaraldehyde, 5-hydroxymethylfurfural, acrolein, levulinate esters, sugars, 2,5-furandicarboxylic aldehyde, difurfural (DFF), glycerol, sorbitol, or mixtures thereof.
• furfuryl alcohol furfural
• glyoxal acetaldehyde
• glutaraldehyde glutaraldehyde
• 5-hydroxymethylfurfural acrolein
• levulinate esters sugars
• 2,5-furandicarboxylic aldehyde difurfural (DFF), glycerol, sorbitol, or mixtures thereof.
• DFF difurfural
• any suitable saturated or unsaturated organic anhydride can be used including, but not limited to maleic anhydride, acetic anhydride, succinic anhydride, itaconic anhydride, phthalic anhydride and trimelletic anhydride.
• the organic anhydride comprises maleic anhydride.
• any suitable polyamine can be used including, but not limited to urea, melamine, and hexamine.
• the polyamine is urea and the organic anhydride is maleic anhydride
• the acid catalyzed tannin-based resin may comprise one or more surfactants, with at least an ethoxylated castor oil as one of the one or more surfactants.
• a class of suitable surfactants includes non-ionic organic surfactants such as the condensation products of alkylene oxides such as ethylene oxide, propylene oxide or mixtures thereof, and alkylphenols such as nonylphenol, dodecylphenol, and the like.
• Suitable non-ionic organic surfactants include, but are not limited to, ethoxylated castor oil available from Lambent Technologies; polysorbate (Tween®) surfactants available from Sigma-Aldrich Chemical Company; Pluronic® non-ionic surfactants available from BASF Corp., (Florham Park, NJ); TergitolTM; Brij® 98, Brij® 30, and Triton X 100, all available from Aldrich Chemical Company.
• siloxane-oxyalkylene copolymers such as those containing Si-O-C as well as Si-C linkages.
• the siloxane-oxyalkylene copolymers can be block copolymers or random copolymers.
• Typical siloxane-oxyalkylene copolymers contain a siloxane moiety composed of recurring dimethylsiloxy units endblocked with mononethylsiloxy and/or trimethylsiloxy units and at least one
• siloxane-oxyalkylene copolymeric surfactants include, but are not limited to, polyether-modified polysiloxanes, available as Tegostab B8406 from Evonik Goldschmidt Corporation (Hopewell, VA); (polyalkyleneoxide modified heptamethyltrisiloxane available as Silwet L-77 from
• the acid catalyzed tannin-based resin present in the formaldehyde- free polymeric phase may comprise one or more acid catalysts.
• Suitable acid catalysts include, but are not limited to, benzenesulfonic acid, para- toluenesulfonic acid, xylenesulfonic acid, naphthalenesulfonic acid, ethylbenzenesulfonic acid, phenolsulfonic acid, sulfuric acid, phosphoric acid, boric acid, hydrochloric acid or mixtures thereof.
• the acid catalyst is a mixture of two of more aromatic sulfonic acids selected from the group consisting of benzenesulfonic acid, para- toluenesulfonic acid, xylenesulfonic acid, naphthalenesulfonic acid, ethylbenzenesulfonic acid and phenolsulfonic acid.
• the formaldehyde-free polymeric phase of the present disclosure comprising an acid catalyzed tannin-based resin may also comprise one or more additives.
• Suitable additives include, but are not limited to, cellulose fiber, bacterial cellulose, sisal fiber, clays, Kaolin-type clay, mica, vermiculite, sepiolite, hydrotalcite and other inorganic platelet materials, glass fibers, polymeric fibers, alumina fibers, aluminosilicate fibers, carbon fibers, carbon nanofibers, poly-1 ,3-glucan, lyocel fibers, chitosan, boehmite (AIO.OH), zirconium oxide, or mixtures thereof.
• the acid catalyzed tannin-based resin may also include at least one of a polyester polyol or a polyether polyol as an optional plasticizer.
• the polyester polyol can be formed by the reaction of a polybasic carboxylic acid with a polyhydridic alcohol selected from a dihydridic to a pentahydridic.
• examples of the polybasic carboxylic acid include but are not limited to adipic acid, sebacic acid, naphthalene-2,6- dicarboxylic acid, cyclohexane-1 ,3-dicarboxylic acid, phthalic acid.
• the polyhydric alcohol examples include but are not limited to ethylene glycol, propylene diol, propylene glycol, 1 ,6-hexane diol, 1 ,4-butane diol and 1 ,5-pentane diol.
• the plasticizer is an aromatic polyester polyol derived from phthalic anhydride and diethylene glycol. The average molecular weight of the polyester polyol is in the range of 100-5,000 g/mol, or 200-2,000 g/mol, or 200-1000 g/mol.
• Polyether polyols are made by reacting epoxides like ethylene oxide or propylene oxide with the multifunctional initiator in the presence of a catalyst, often a strong base such as potassium hydroxide or a double metal cyanide catalyst.
• a catalyst often a strong base such as potassium hydroxide or a double metal cyanide catalyst.
• Common polyether polyols are polyethylene glycol,
• polyester polyol polypropylene glycol, and poly(tetramethylene ether) glycol.
• the average molecular weight of the polyester polyol is in the range of 100-5,000 g/mol, or 150-2,000 g/mol, or 200-1000 g/mol
• the condensed tannin-based foam as disclosed hereinabove comprising a formaldehyde-free polymeric phase defining a plurality of cells (closed cells and open cells) also comprises one or more blowing agent disposed in at least a portion of the plurality of closed-cells and wherein at least one of the one or more blowing agents is an azeotrope or an azeotrope-like mixture of isopentane and one other blowing agent selected from the group consisting of isopropyl chloride, 1 ,1 ,1 ,4,4,4- hexafluoro-2-butene and 1 -chloro-3,3,3,-trifluoropropene.
• the blowing agent is a mixture of isopentane and isopropyl chloride.
• At least one or more blowing agents has an ozone depletion potential (ODP) of less than 2, or less than 1 or 0 and has a global warming potential (GWP) of less than 5000, or less than 1000, or less than 500.
• ODP ozone depletion potential
• GWP global warming potential
• An exemplary blowing agent with zero ODP and a low GWP is a mixture of isopentane and isopropyl chloride (ODP of 0 and GWP of less than 20).
• the condensed tannin-based foam of the present disclosure has an open-cell content of less than 15% (or closed-cell content greater than 85%), or less than 12%, or less than 10%, or less than 8%, as measured according to ASTM D6226-5.
• the condensed tannin-based closed-cell foam has an initial thermal conductivity of less than 23 mW/m-K, measured at 25 °C. In an embodiment, the condensed tannin-based closed-cell foam has an aged thermal conductivity of less than 25 mW/m-K, measured at 25 °C.
• the overall conductivity of the foam is strongly determined by the thermal conductivity of the blowing agent and the open-cell content of the foam. This is because the blowing agent disposed in at least a portion of the plurality of the closed-cells in a low-density foam (having a density in the range of 20-45 kg/m 3 ), usually makes up about 95% of the total foam volume.
• the condensed tannin-based foam has a density in the range of 10-250 kg/m 3 or 20-50 kg/m 3 or 30-40 kg/m 3 .
• the condensed tannin-based foam as disclosed herein above is derived from a formaldehyde-free foamable composition comprising a surface-active condensed tannin, furfuryl alcohol, maleic anhydride, urea, an ethoxylated castor oil, an aromatic sulfonic acid, and a mixture of isopentane and isopropyl chloride.
• the insulation material exhibit low flammability besides low thermal conductivity. Flammability of a material may be evaluated by several different methods known to those skilled in the art. One method is to measure the Limiting Oxygen Index (LOI), which represents the concentration of oxygen required to sustain a flame during the burning of a material (ASTM 2863). The higher the LOI of a material the lower is its flammability. Thus it is desirable that insulating foams exhibit as high a LOI as possible. In an embodiment, the disclosed foam has a limiting oxygen index (LOI) of or at least 25 or at least 28 or at least 30.
• LOI Limiting Oxygen Index
• Flammability can also be assessed using a cone calorimeter in accordance with ASTM E1354.
• the fire properties that can be measured in the cone calorimeter include heat release rate and its peak, the mass loss and char yield, effective heat of combustion and combustion efficiency, time to ignition, flame out time, and CO and smoke production.
• the condensed tannin-based foams of the present disclosure containing maleic anhydride self-extinguish faster than the foams without maleic anhydride.
• the condensed tannin-based foams of the present disclosure containing maleic anhydride self-extinguish in less than 50 seconds after ignition.
• the size of the cells in a foam can also affect the resulting thermal conductivity.
• the cell size of the foam can also affect other properties of the foam, such as but not limited to the mechanical properties.
• the size of the cells cannot be reduced indefinitely because for a given density foam if the cell size becomes too small the thickness of the cell walls can become exceedingly thin and hence can become weak and rupture during the blowing process or during use.
• a cell either an open-cell or a closed-cell, has an average size of in the range of 50-500 microns.
• the cell has an average size in the range of 50-300 microns and in yet another embodiment the cell has an average size in the range of 80-200 microns.
• Cell size may be measured by different methods known to those skilled in the art of evaluating porous materials. In one method, thin sections of the foam can be cut and subjected to optical or electron microscopic measurement, such as using a Hitachi S2100 Scanning Electron
• the condensed tannin-based foam, as disclosed hereinabove is disposed between two similar or dissimilar non- foam materials, also called facers to form a sandwich panel structure.
• Any suitable material can be used for the facers.
• the facers may be formed from a metal such as, but not limited to aluminum and stainless steel.
• the facers may be formed from plywood, cardboard, composite board, oriented strand board, gypsum board, fiber glass board, and other building materials known to those skilled in the art.
• the facers may be formed from nonwoven materials derived from glass fibers and/or polymeric fibers such as Tyvek® and Typar® available from E. I. DuPont de Nemours &
• the facers may be formed from woven materials such as canvas and other fabrics. Yet, in another embodiment, the facers may be formed of polymeric films or sheets. Exemplary polymers for the facer may include, but are not limited to, polyethylene, polypropylene, polyesters, and polyamides. The thickness of the facer material would vary depending on the application of the sandwich panel. In some cases, the thickness of the facer material could be significantly smaller than the thickness of the foam while in other cases the thickness of the facer material could be comparable or even greater than the thickness of the sandwiched foam.
• the disclosed condensed tannin-based foams are bio-derived, low density rigid foams, having low aged thermal conductivity, low flammability and low water vapor absorption.
• the disclosed condensed tannin-based foams could be used for a variety of applications, including, but not limited to, thermal insulation of building envelopes, and household and industrial appliances.
• the disclosed condensed tannin-based foams can also be used in combination with other materials such as silica aerogels as a support for the fragile aerogel, and potentially as a catalyst support.
• Potential advantages of the disclosed condensed tannin-based foams include, but are not limited to, the use of less toxic materials, zero formaldehyde emission, improved flame resistance, mold resistance, and micro-organism resistance.
• a process of making a condensed tannin-based foam comprises forming an agglomerate free solution comprising a surface- active condensed tannin, a tannin-reactive monomer, and water.
• the surface-active condensed tannin as disclosed hereinabove has a surface tension of less than 53.0 mlM/m when dissolved in 50 wt% of water.
• the surface-active condensed tannin is a volatile-free condensed tannin, as disclosed hereinabove.
• the amount of dried surface-active condensed tannin is in the range of 10-80%, or 20 - 80%, or 50-80%, by weight, based on the total weight of the
• Any suitable formaldehyde-free tannin-reactive monomer, as disclosed hereinabove may be used.
• the amount of the formaldehyde-free tannin-reactive monomer present in the solution is in the range of 5- 80%, or 10-50%, or 10-30%, by weight, based on the total weight of the formaldehyde-free foamable composition.
• the step of forming an agglomerate free solution comprises mixing the surface-active condensed tannin with a formaldehyde-free tannin- reactive monomer, and water to form a mixture and providing a residence time to the mixture to effectively dissolve the tannin in the mixture.
• the mixture may comprise agglomerates of tannin, wherein one may observe a two phase system with one phase being agglomerates of tannin and the other phase being liquid comprising dissolved tannin in a monomer, and water. As the agglomerates of tannin dissolves, the mixture becomes more viscous.
• the mixture is a one phase system comprising dissolved tannin in a monomer, and water.
• the step of providing a residence time may involve keeping the mixture still for the residence time, or mixing the mixture for a certain amount of time, or mixing and keeping still for the rest of the residence time.
• the amount of residence time needed to obtain an agglomerate-free solution will depend on the temperature at which the tannin is mixed with the monomer and water and also on the composition and the extent of mixing.
• Any suitable method can be used to mix the surface-active condensed tannin with the tannin-reactive monomer, and water, to form an agglomerate-free solution, such as, for example, hand mixing, mechanical mixing using a Kitchen-aid® mixer, a twin screw extruder, a bra-blender, an overhead stirrer, a ball mill, an attrition mill, a Waring blender, or a combination thereof.
• the step of forming the agglomerate-free solution comprising a surface-active condensed tannin, a tannin-reactive monomer, and water can include first mixing the tannin with water and then adding the monomer to the mixture of tannin and water.
• the step of forming an agglomerate-free solution comprising a surface-active condensed tannin, a tannin-reactive monomer, and water can include first mixing the tannin with the monomer and then adding water to the mixture of tannin and monomer.
• the step of forming an agglomerate-free solution comprising a surface-active condensed tannin, a tannin-reactive monomer, and water can include first mixing the monomer with water and then adding surface-active condensed tannin to the mixture of tannin-reactive monomer and water.
• the process of making a condensed tannin-based foam also comprises adding a saturated or an unsaturated organic anhydride and a blowing agent to the agglomerate free solution to form a pre-foam mixture.
• the process also comprises adding an acid catalyst to the pre-foam mixture to form a formaldehyde-free foamable composition.
• the amount of organic anhydride is in the range of 0.5-20%, or 1- 15%, or 1-10%, based on the total weight of the formaldehyde-free foamable composition.
• the organic anhydride comprises maleic anhydride.
• the process of making a condensed tannin-based foam also comprises adding 0.5-20% or 1-10% by weight of polyamine to the agglomerate free solution, such that the organic anhydride and the polyamine are present in a weight ratio of 1 :0.1 to 1 :1 , wherein the polyamine comprises at least one of urea and melamine.
• polyamine is urea
• the amount of blowing agent is in the range of 0.5-20%, or 1-15%, or 1-10%, by weight, based on the total weight of the formaldehyde-free foamable composition.
• the blowing agent comprises an azeotrope or an azeotrope-like mixture of isopentane and one other blowing agent selected from the group consisting of isopropyl chloride, 1 ,1 ,1 ,4,4,4-hexafluoro-2-butene and 1 -chloro-3,3,3,-trifluoropropene.
• the blowing agent comprises a mixture of isopropyl chloride and isopentane present in a weight ratio of 90:10 or 75:25 or 50:50 or 10:90.
• the process of making a condensed tannin-based foam also comprises adding a surfactant to the agglomerate free solution.
• a surfactant is added to the pre-foam mixture.
• the surfactant is first mixed with the blowing agent and then the mixture of blowing agent and surfactant is mixed with the agglomerate-free solution to form a pre-foam mixture.
• a surfactant is mixed with the acid catalyst.
• the amount of surfactant present in at least one of the agglomerate-free solution, the pre-foam mixture, or the formaldehyde- free foamable composition is in the range of 0.5-10%, or 2-8%, or 3-6%, by weight, based on the total weight of the formaldehyde-free foamable composition .
• the surfactant is present in an effective amount to emulsify the formaldehyde-free foamable composition comprising surface-active condensed tannin, tannin-reactive monomer, the saturated or an unsaturated organic anhydride, the blowing agent, the catalyst and optional additives of the foamable composition.
• the surfactant is added to lower the surface tension and stabilize the foam cells during foaming and curing.
• the surfactant is an ethoxylated castor oil, as disclosed hereinabove.
• the process of making a condensed tannin-based foam further comprises adding an additive, disclosed hereinabove to at least one of the agglomerate-free solution or the pre-foam mixture.
• the amount of additive is in the range of 5-50%, or 10-45%, or 15-40%, by weight based on the total weight of the agglomerate-free solution.
• the additive is a plasticizer comprising a polyester polyol, as disclosed hereinabove.
• the amount of acid catalyst disclosed hereinabove is in the range of 1-20% or 5-20% or 5-15%, by weight, based on the total weight of the formaldehyde-free foamable composition.
• the acid catalyst comprises para-toluenesulphonic acid and xylenesulphonic acid in a weight ratio in the range of 0.67:1 to 9:1 , or 2:1 to 7:1 , or 3:1 to 5:1 .
• the acid catalyst may be dissolved in a minimum amount of solvent, the solvent comprising ethylene glycol, 1 ,2-propylene glycol, triethylene glycol, butyrolactone, dimethyl sulfoxide, /V-methyl-2- pyrrolidone, morpholines, 1 ,3-propanediol, or mixtures thereof.
• a catalyst is normally required to produce the foam but in some cases, a foam can be made without a catalyst but rather using thermal aging. A combination of thermal aging and a catalyst is commonly used. In some cases, the reaction is exothermic and hence little or no additional heat may be required.
• the process of making a condensed tannin-based foam also comprises foaming and curing the formaldehyde-free foamable
• the step of processing the formaldehyde- free foamable composition comprises maintaining the formaldehyde-free foamable composition at an optimum temperature.
• the optimum temperature is in the range of 50-100 °C, or 60-90 °C.
• the step of processing the formaldehyde-free foamable composition comprises foaming the formaldehyde-free foamable composition in a substantially closed mold or in a continuous foam line.
• the formaldehyde-free foamable composition is first foamed at an optimum temperature in the range of 50-100 °C, or 60-90 °C in an open mold and then the mold is closed and kept at that temperature for a certain amount of time.
• the foam is formed in a closed mold or under application of pressure to control the foam density. Pressures from atmospheric to up to 5000 kPa may be applied depending upon the desired foam density.
• the process may further comprises disposing the condensed tannin-based foam between two similar or dissimilar non-foam materials, also called facers to form a sandwich panel structure.
• facers any suitable material can be used for the facers, as disclosed hereinabove.
• the facer material may be physically or chemically bonded to the condensed tannin-based foam to increase the structural integrity of the sandwich panel.
• Any suitable method can be used for physical means of bonding including, but not limited to, surface roughening by mechanical means and etching by chemical means.
• Any suitable method can be used for chemical bonding including, but not limited to, use of coatings, primers, and adhesion promoters that form a tie layer between the facer surface and the foam.
• a mixed tannin-phenolic foam formed by foaming and curing a foamable composition comprising a tannin-phenolic resole mixture, which is derived from:
• phenol-reactive monomer and further comprises urea
• the tannin-reactive monomer of the present teachings exclude formaldehyde, the overall amount of formaldehyde in the a mixed tannin-phenolic foam of the present teachings is lower than the phenolic- resole prepolymer, thereby making the mixed tannin-phenolic foams of the present disclosure with improved benefits in terms of exposure and emission of formaldehyde.
• a process of making a mixed tannin-phenolic foam comprises first forming a volatile-free condensed tannin by heating a surface-active condensed tannin at a temperature in the range of 1 10-200 °C or
• the process further comprises forming an agglomerate-free tannin solution, as disclosed hereinabove, except that the agglomerate-free tannin solution comprises a volatile-free condensed tannin, obtained by thermal treatment of a surface-active condensed tannin, dissolved in water and a tannin-reactive monomer.
• the agglomerate-free tannin solution comprising volatile-free condensed tannin, furfuryl alcohol and water, has a viscosity in the range from 1000 to 150000 cP or 2000 to 100000 cP or 5000 to 50000 cP at 25 °C.
• the amount of the formaldehyde-free tannin- reactive monomer, disclosed hereinabove is present in the agglomerate- free tannin solution in the range of 5-80%, or 10-50%, or 10-30%, by weight, based on the total weight of the tannin solution comprising volatile- free condensed tannin, water and tannin-reactive monomer.
• the process of making a mixed tannin-phenolic foam further comprises adding 10-90% or 20-80% or 25-70%, by weight of a phenolic-resole prepolymer to the tannin solution to form a tannin-phenolic resole mixture.
• the phenolic-resole prepolymer is derived from a phenol and a phenol-reactive monomer and further comprises urea.
• Suitable phenols include, but are not limited to, unsubstituted phenol, ethyl phenol, p-tertbutyl phenol; ortho, meta, and para cresol; resorcinol; catechol; xylenol; and the like.
• Suitable phenol-reactive monomer include, but are not limited to, at least one of formaldehyde, paraformaldehyde, furfuryl alcohol, furfural, glyoxal, acetaldehyde, glutaraldehyde, 5-hydroxymethylfurfural, levulinate esters, sugars, 2,5-furandicarboxylic aldehyde, difurfural (DFF) and sorbitol.
• formaldehyde paraformaldehyde
• furfuryl alcohol furfural
• glyoxal acetaldehyde
• glutaraldehyde glutaraldehyde
• 5-hydroxymethylfurfural levulinate esters
• sugars 2,5-furandicarboxylic aldehyde
• DFF difurfural
• the phenolic-resole prepolymer is derived from an unsubstituted phenol, a phenol-reactive monomer and urea and has a number average molecular weight of less than 1500 or less than 1000 and has a viscosity less than 30,000 cPs or less than 15,000 cPs at 25 °C.
• the phenolic-resole prepolymer is derived from a phenol, formaldehyde, and urea. In another embodiment, the phenolic- resole prepolymer is derived from a phenol, urea, formaldehyde and at least one bio-based phenol-reactive monomer selected from the group consisting of furfuryl alcohol, furfural, glyoxal, 5-hydroxymethylfurfural, levulinate esters, sugars, 2,5-furandicarboxylic aldehyde, difurfural (DFF) and sorbitol.
• DFF difurfural
• the phenolic-resole prepolymer is derived from a phenol, a phenol-reactive monomer, urea.
• the process further comprises adding at least one surfactant, one blowing agent and an aromatic sulfonic acid to the tannin-phenolic resole mixture, similar to that described for the process of making condensed tannin-based foam, with the difference being of adding blowing agent, acid catalyst, optional urea, plasticizer to the tannin-phenolic resole mixture, as opposed to the tannin.
• the process further comprises optionally adding 0.5-20%, or 1- 15%, or 1-10% of a saturated or an unsaturated organic anhydride, 0.5- 20% by weight of polyamine to the tannin-phenolic resole mixture.
• the process further comprises adding 0.5-20% or 1-15%, or 1-10% by weight of a blowing agent to form a pre-foam tannin-phenolic resole mixture.
• the process also comprises adding 1-20% by weight of an acid catalyst to the pre-foam tannin-phenolic resole mixture to form a tannin-phenolic resole foamable composition, wherein the amount is based on the total weight of the mixed tannin-phenolic foam composition, excluding the weight of blowing agent.
• blowing agent comprises a mixture of isopropyl chloride and isopentane present in a weight ratio of 90:10 or 75:25 or 50:50 or 10:90.
• the acid catalyst comprises para- toluenesulphonic acid and xylenesulphonic acid in a weight ratio in the range of 0.67:1 to 9:1 , or 2:1 to 7:1 , or 3:1 to 5:1 .
• the aromatic sulfonic acid may be dissolved in a minimum amount of solvent, as disclosed hereinabove.
• the organic anhydride comprises maleic anhydride.
• the process of making a mixed tannin-phenolic foam also comprises foaming and curing the tannin-phenolic resole foamable composition at a temperature in the range of 50-100 °C or 60-90 °C to form a mixed tannin-phenolic foam comprising a polymeric phase defining a plurality of cells, and wherein one or more blowing agents is disposed in at least a portion of the plurality of cells.
• the step of processing the tannin-phenolic resole foamable composition comprises foaming the composition in a substantially closed mold or in a continuous foam line or in an open mold, similar to the process for making condensed tannin- based foams, as disclosed hereinabove.
• the mixed tannin-phenolic foam is derived from a volatile-free condensed tannin, furfuryl alcohol, a phenolic resole prepolymer, a mixture of isopropyl chloride and isopentane, urea, an ethoxylated castor oil based surfactant, an aromatic sulfonic acid catalyst, and an optional plasticizer comprising at least one of a polyester polyol or a polyether polyol.
• the process of making a tannin-based foam further comprises disposing a tannin-based foam between two similar or dissimilar non-foam materials, also called facers to form a sandwich panel structure.
• Apparent density (p) of the foams was measured by a) cutting a foam into a regular shape such as a rectangular cube or cylinder, b) measuring the dimensions and the weight of the foam piece, c) evaluating the volume of the foam piece and then dividing the weight of the foam piece by the volume of the foam piece.
• Open-cell content of foams was determined using ASTM standard D6226-5. All measurements were made at room temperature of 24 °C.
• Pycnometer density (p) of each cylindrical piece was measured using a gas pycnometer, Model # Accupyc 1330 (Micromeritics Instrument Corporation, Georgia, U.S.A) at room temperature using nitrogen gas.
• the AccuPyc works by measuring the amount of displaced gas.
• a cylindrical foam piece was placed in the pycnometer chamber and by measuring the pressures upon filling the chamber with a test gas and discharging it into a second empty chamber, volume (V s ) of the cylindrical foam piece that was not accessible to the test gas was calculated. This measurement was repeated five times for each foam cylindrical piece and the average value for V s was calculated.
• the volume fraction of open-cells (O v ) in a foam sample was calculated by the following formula:
• Hot Disk Model # PPS 2500S (Hot Disk AB, Gothenberg, Sweden) was used to measure thermal conductivities of the foams.
• a foam whose thermal conductivity needed to be measured was cut into two rectangular or circular test pieces of same size.
• the lateral dimensions and the thickness of the foam pieces were required to be greater than four times the radius of the Hot Disk heater and sensor coil.
• the radius of the heater and sensor coil for all measurements was 6.4 mm and hence the lateral dimensions and the thickness of the foam pieces were greater than 26 mm.
• the heater and sensor coil was sandwiched between two test pieces of foam and the entire assembly was clamped together to ensure intimate contact between the surfaces of the foam pieces and the heater and sensor coil.
• a known current and voltage was applied to the heater and sensor coil.
• the resistance of the heater and sensor coil was also measured using a precise wheat stone bridge built into the Hot Disk apparatus. The resistance was used to estimate the instantaneous temperature of the coil.
• the temperature history of the heater and sensor coil was then used to calculate the thermal conductivity of the foam using mathematical analysis presented in detail by Yi He in Thermochimica Acta 436, pp 122-129, 2005.
• the thermal conductivity measurement on the test pieces at room temperature was repeated two more times. The thermal conductivity data was then used to calculate the average thermal conductivity of the foam.
• the foams were aged in oven at 70 °C for 4 days and then at 1 10 °C for 2 weeks and the aged thermal conductivity of the aged foam samples was measured at room temperature as described above.
• the fire resistance properties of the foams were tested using Cone Calorimeter according to ASTM E1354, and Limiting Oxygen Index method according to ASTM D-2863, using a 6"x1 .5"x0.25" foam sample In the cone calorimeter test, a 100 mm x 100 mm x 13.5 foam sample is exposed to radiant heat at a heat flux of 50 kW/m 2 for a minimum of 300 seconds. The average values of three specimens for each sample were reported. The parameters tested include time to ignition (t ig ), peak heat release rate (HRR), average HRR after 180 seconds of burning, effective heat of combustion (EHC), total heat released (THR), average mass loss, average smoke production rate (SPR) and CO/CO2 yield.
• t ig time to ignition
• HRR peak heat release rate
• EHC effective heat of combustion
• THR total heat released
• SPR average mass loss
• CO/CO2 yield CO/CO2 yield.
• Condensed tannin samples were run on a Q500 TGA from TA Instruments. Samples were ramped from room temperature to 600 °C with a 10 °C/min heating rate. Samples were run in duplicate in both air and nitrogen atmospheres.
• Sample preparation and procedure 50 mg of sample in 20 ml_ headspace vials were evacuated and back flushed three times with nitrogen in a vacuum oven at room temperature (22 °C), and were capped quickly and hand-tightened. Each vial was heated to 200 °C for one hour and then 1 .0 ml_ of the headspace was injected via a heated sample loop into the GC/MS. Mass spectra were acquired at two per second. The total ion chromatograms were plotted, and the peak mass spectra were compared to NIST library spectra.
• Mimosa tannin extract (Acacia mearnsii) samples were received from two different sources and were used as received. Tannin-A was purchased from SilvaTeam (Italy) and Tannin-F was purchased from Tanac (Brazil). Furfuryl alcohol, maleic anhydride, and urea were from Sigma-Aldrich (St. Louis, MO). Phenol-formaldehyde (PF-D) resole prepolymers which does not contain urea were obtained from DynaChem, Inc.
• PF-D Phenol-formaldehyde
• Acid catalyst used was a mixture of 70/30 wt% p-toluene sulfonic acid and xylene sulfonic acid in ethylene glycol or triethylene glycol, and it was obtained from DynaChem Inc. Blowing agents used were isopentane and isopropyl chloride (2-chloropropane).
• LUMULSE CO-30Q and LUMULSE CO-40 are ethoxylated castor oils were purchased from Lambent Technologies (Gurnee, IL) and Tegostab® B8406, a silicone surfactant was purchased from Evonik Goldschmidt Corporation (Hopewell, VA).
• Stepanol PS-3152 is a commercial plasticizer purchased from Stepan.
• Aqueous tannin solutions were prepared by dissolving tannin extracts obtained from two different sources (Tannin-A and Tannin-F) in 50 weight% of water, and the surface tension of these two different tannin extract solutions were measured by adding no surfactant.
• the surface tension data is reported in Table 1 .
• a tannin solution (Tannin-F/FA H 2 O) was prepared by dissolving Tannin-F in furfuryl alcohol and water.
• a 50/50 wt% Tannin-F/phenolic resole solution was prepared by mixing phenol-formaldehyde based resole (PF-D) and tannin solutions. The surface tension of this 50/50 Tannin- F/phenolic resole mix was measured with and without surfactant and compared with 100% resole (Table 1 ).
• Table 1 Interaction of surfactant(s) with resole and resole/tannin mix
• the aqueous Tannin-F solution had lower surface tension (42.7 mN/m) than the Tannin-A solution (53.5 mN/m) suggesting that Tannin-F contains surface active components, and the composition of the two tannins is not identical. Furthermore, the surface tension of the neat phenol-based resole prepolymer (61 .4 mN/m) was reduced from 61 .4 to 54.1 mN/m when Tannin-F solution was added without a surfactant.
• a portion of the tannin/FA/water mix solution, plasticizer (Stepanol PS-3152), surfactant (LUMULSE CO-30Q) and maleic anhydride were added in 100 ml_ beaker, mixed thoroughly and cooled in an ice bath.
• plasticizer Steppanol PS-3152
• surfactant LUMULSE CO-30Q
• maleic anhydride 100 ml_ beaker, mixed thoroughly and cooled in an ice bath.
• IPC/IP isopropyl chloride/isopentane
• composition was transferred quickly from beaker into non-stick paper box mold (3"x 3"x 3") previously heated in oven at 70 °C.
• This paper box was inserted in a metal mold having the same dimensions of paper box mold and closed tightly.
• the condensed tannin-based foam was taken out from the metal mold and the paper box, was placed in another oven and post-cured the foam at 70 °C for overnight.
• the properties of the cured condensed tannin-based foam are reported in Table 2.
• Example 1 was repeated with the exception that amount of maleic anhydride was different.
• the composition and the properties of the as- prepared condensed Tannin-based foam are summarized in Table 2.
• Example 1 was repeated with the exception that no maleic anhydride was added.
• the composition and the properties of the as- prepared condensed Tannin-based foam are summarized in Table 2.
• the foams with increased amount of maleic anhydride decreased their affinity towards moisture present in air after normalizing for the density, as shown in Figure 1 , which shows the effect of maleic anhydride on moisture absorption.
• the foams in general with low moisture absorption can have stable insulation performance.
• Example 4 & 5 Effect of foaming and curing temperatures on the Condensed Tannin-based Foams Properties
• Example 1 was repeated as-is (Example 4) and with a different foaming and curing temperature of 55 °C (Example 5).
• the composition and the properties of the as-prepared condensed tannin-based foams are summarized in Table 3.
• Example 4 the foam cured at 70 °C has lower open-cell content (6.9%) as compared to Example 5 (9.8%), where the foam was cured at 55 °C. This may be explained by faster crosslinking reaction rate between tannin and furfuryl alcohol at higher temperatures, making the cells more stable, smaller and stronger, leading to foams with higher closed-cells, lower density and lower thermal conductivity compared to foams made at lower temperatures.
• Examples of 6-9 were the repeat of Example 1 with the exception that varied amounts of urea and maleic anhydride were used as shown in Table 4. The cured foam properties are reported in Table 4.
• Example 6 was repeated with the exception that no maleic anhydride was added and the amount of urea was 1 .5 wt%.
• the cured foam properties are reported in Table 4.
• Example 2 Two condensed tannin-based foams were prepared as described in Example 2. These two foams were aged in oven at 70 °C for 4 days and then at 1 10 °C for 2 weeks and the thermal conductivity was measured at room temperature and found to be 22.1 and 22.2 mW/m.K respectively.
• Example 12 Fire properties of Condensed Tannin-Based Foam containing maleic anhydride
• a tannin-based foam was prepared as described in Example 2 with the following ingredients: Tannin/FA/water mix solution, Stepanol PS-3152 (1 .23%), LUMULSE CO-40 (2.16%), maleic anhydride (1 .5%), a mixture of isopropyl chloride/isopentane (7.36%) and 70/30 mixture of p- toluenesulfonic acid/xylenesulfonic acid (12.68%) in 30 % ethylene glycol. About 67 g of the composition was poured in 6"X6"X2" mold. The foaming and curing temperatures were 60 and 70 °C respectively.
• Comparative Example C Identical foam sample was prepared as described above without using maleic anhydride.
• the tannin-based foam that contained maleic anhydride self- extinguished in 34 seconds much faster than the foam that contained no maleic anhydride (51 seconds).
• Example 13 Fire properties of Condensed Tannin-Based Foam containing maleic anhydride
• a tannin-based foam was prepared as described in Example 12 with the following ingredients: Tannin/FA water mix solution, Stepanol PS- 3152 (1 .2%), LUMULSE CO-30Q (2.2%), maleic anhydride (0.75%), a mixture of isopropyl chloride/isopentane (7.3%) and 70/30 mixture of p- toluenesulfonic acid/xylenesulfonic acid (12.6%) in 30 % ethylene glycol.
• the composition was foamed and cured in a closed mold with dimensions 6"x6"x2" at 70 °C.
• the Limiting Oxygen Index (LOI) method was used to measure the flammability of the foam according to ASTM D-2863 and the LOI value for the tannin based foam was found to be 31 .
• the tannin-foamable compositions that contained maleic anhydride results in foams with improved dimensional stability, low initial and aged thermal conductivities, high closed-cell content, less sensitive to moisture and urea, and good fire resistance.
• Phenol-formaldehyde (PF-M) resole prepolymer containing urea was used to prepared mixed Tannin-Phenolic foams.
• the resole prepolymer was characterized and had the following properties:
• Weight average molecular weight (Mw) 905
• thermoset rigid foam A typical preparation of mixed Tannin-Phenolic resole foamable composition and foaming process to form thermoset rigid foam is described below. The actual amounts of various ingredients added and the calculated weight percentage of each ingredient to the total weight of the composition are reported in Table 6.
• tannin/FA water solution An agglomerate free stock solution of tannin, furfuryl alcohol and water was prepared from commercial Tannin-F using the procedure described hereinabove and will be referred to as the tannin/FA water solution.
• prepolymer, plasticizer (Stepanol PS-3152), and surfactant (LUMULSE CO-30Q) were added in 100 ml_ beaker, mixed thoroughly and cooled in an ice bath.
• a mixture of isopropyl chloride/isopentane (IPC/IP) (3:1 weight ratio) was added incrementally and mixed the solution.
• the beaker containing the solution was weighed and additional amount of the IPC/IP mixture was added to compensate evaporated amount during the mixing.
• Tannin-F 250 g was placed in rectangular container having 220 cm 2 surface area and dried at 130 °C for 4 days in an oven with combined nitrogen flow and vacuum to flush out moisture and volatile impurities. After drying the observed weight loss was found to be 10.92 %. The volatile-free condensed Tannin-F was used to prepare
• Table 7 reports the surface tension of 50 wt% aqueous solutions of commercial as-received Tannin-A and as-received Tannin-F, and volatile- free condensed Tannin-F obtained by heating as-received Tannin-F at 130 °C for 3 days in air.
• TGA analysis To understand the effect of thermal pre-treatment of Tannin-F in air or nitrogen at 130 °C on the composition, weight loss experiments were conducted both in air and nitrogen atmosphere on the following four samples: (i) Tannin-A as received, (ii) Tannin-F as received, (iii) volatile-free Tannin-F obtained by heating as-received Tannin-F at 130 °C in air, and (iv) volatile-free Tannin-F obtained by heating as-received Tannin-F at 130 °C in nitrogen. Table 8 reports the weight loss of the samples at three temperature regions: RT-140 °C, 140-300 °C and 300- 600 °C.
• Table 8 Weight losses of condensed tannins as a function of temperature
• Tannin-F had the highest weight loss in the 140-300 °C region (17.0-17.2 wt%), followed by Tannin-A (15.9-16.2 wt%), volatile- free Tannin-F, pre-heated in nitrogen (13.4 wt%) and volatile-free Tannin- F, pre-heated in air (12.2-12.9 wt%).
• Tannin-A had weight loss (around 16%) closer to that of Tannin-F (around 17%), the foams prepared from Tannin-A had good insulation performance in the presence of urea (Comparative example H) suggesting the composition of Tannin-A differs from Tannin-F.
• the higher performance of Tannin-A may be due to absence of components that interfere with urea.
• Figures 2A and 2B shows GC-MS headspace spectra of
• Tannin-F mass spectral library and their associated GC retention times in minutes are listed below. It is speculated that the presence of high boiling volatile components in Tannin-F may be due to the nature of plant source, extraction method or any added additives after the extraction. From the Figure 2B and the foam data in Table 6, it is concluded that the high boiling volatiles (boiling points greater than 277 °C) present in Tannin- F were interfering with urea present in resole and led to poor insulation performance of the foam.
• Tannin-F low boiling volatile components (boiling points lower than 277 °C) which are present in Tannin-F are also present in Tannin-A despite of the fact that the two tannins belong to different regions of the world and their extraction methods might not be identical. Since Tannin-A had no impact on thermal insulation performance of a bio- based foam derived from tannin/PF-M resole mixture in the presence of urea, it was assumed that the low boiling volatile components do not affect the insulation performance.
• Figures 3A, 3B, and 3C show GC-MS headspace spectra of commercial condensed tannin extracts: as-received Tannin-F; pre-heated Tannin-F in air; and pre-heated Tannin-F in nitrogen respectively.
• the absence of high boiling volatile components is evident in pre-heated Tannin-F samples both in air and in nitrogen at 130 °C, and the volatile profile of the pre-heated Tannin-F samples are closely matched with that of Tannin-A rather than Tannin-F.
• the peak areas for resorcinol were measured in spectra of untreated and pre-heated Tannin-F samples to estimate the amount of high volatile components reduced during thermal pre-treatment.
• the resorcinol peak area in untreated Tannin-F sample was found to be 3.77 x 10 "5 and this peak area was decreased in heated Tannin-F samples to 0.68 and 0.38 x 10 "5 in nitrogen and in air respectively, and accounts to 80-90% decrease. Therefore it is concluded that the high boiling volatile components were decreased by 80-90% in heated tannin samples.
• the thermal treatment of Tannin-F clearly suggests that the high boiling volatile components present in Tannin-F may be either boiled-off and/ or reacted to form nonvolatile components. As a result, the urea had no impact on pre-heated tannin and the foams obtained from pre-heated Tannin-F had excellent thermal insulation performance.
• the volatile components identified in Tannin-F as received are: Methanol (2.252 min), water (1 .8-2.8), acetone (3.009), furan (3.042), methyl acetate(3.387), formic acid (3.693), propanal, 2-methyl- (3.759), 2,3-butanedione (4.151 ), furan, 2-methylacetic (4.337), acetic acid (4.749), 2-propanone, 1 -hydroxy (5.419), pyridine (6.495), 3(2H)-furanone,dihydro- 2-methyl- (7.31 1 ), furfural (7.703), 2-propanone, 1 -(acetyloxy)-or a diester (8.015), 4-cyclopentene-1 ,3-dione (8.413), furan,2-ethyl-5-methyl- (8.752), butyrolactone (8.818), 1 ,2-cyclopentanedione (8.945), 2,5- furandione,dihydro
• Tannin-F was pre-heated at 130 °C in air for 3 days to obtain volatile-free Tannin-F.
• a tannin solution (Tannin/FA/water) was prepared using the volatile-free Tannin-F, furfuryl alcohol and water.
• a tannin/PF resole mixture was prepared by mixing tannin solution, PF-M resole, plasticizer (Stepanol PS-3152) and surfactant (LUMULSE CO-30Q) in 100 mL beaker and cooled in an ice bath.
• a mixture of isopropyl chloride/isopentane (3:1 weight ratio) was added incrementally and mixed.
• the beaker containing the tannin/PF resole mixture was weighed and additional amount of isopropyl chloride/ isopentane mixture was added to compensate evaporated amount during the mixing. After cooling the mixture again in ice bath, a 70/30 mixture of p-toluenesulfonic acid/xylenesulfonic acid (a 70% solution in ethylene glycol) which was precooled at -10 °C was added and mixed thoroughly for 30 seconds.
• Example 15 In this example, the volatile-free Tannin-F was obtained by heating Tannin-F in nitrogen atmosphere at 130 °C for 4 days.
• the foam was prepared as described in Example 14 except slightly higher acid catalyst amount was used in the foam formulation and the foam was molded in 6"X6"X2" mold with about 67 g of foamable product placing in the mold
• Example 16 A foam was prepared as described in Example 15 except the acid composition, 80% acid in 20% triethylene glycol, was used instead 70% acid in 30% ethylene glycol.
• Example 17 A foam was prepared as described in Example 16 except maleic anhydride was added with no plasticizer and ethoxylated surfactant LUMULSE CO-40 was used instead of LUMULSE CO-30Q.
• composition, process conditions and foam properties are reported in Table 9.
• Comparative Example H A foam was prepared as described in Example 14 with the exception that both foaming and curing was done at
• Table 9 Composition, process conditions and properties of the mixed Tannin-Phenolic foams by using pre-heated Tannin-At 130 °C.
• the data in Table 9 surprisingly shows that the foams, prepared from the commercial Tannin-F that was pretreated at 130 °C either in air or nitrogen atmosphere for 3-4 days, with excellent thermal insulation performance.
• the thermal conductivity of the foams was dropped significantly from 31 (see comparative examples D & E in Table 6) to 22- 24 mW/mK and the open cell content of the foams was reduced to less than 10% (or closed cell content was greater than 90%).
• a rigid mixed tannin-phenolic foam was prepared as described in Example 16 and aged in oven at 70 °C for 4 days and then at 1 10 °C for 2 weeks and the thermal conductivity was measured at room temperature and found to be 23.5 mW/mK.
• a rigid mixed tannin-phenolic foam was prepared as described in Example 16 except no plasticizer was added to the formulation.
• the foam was aged in oven at 70 °C for 4 days and then 1 10 °C for 2 weeks and the thermal conductivity was measured at room temperature and found to be 22.8 mW/mK.
• a volatile-free condensed tannin was obtained by heating as- received Tannin-F at 150 °C in nitrogen for 8 hours.
• a tannin solution (tannin/FA H 2 O) was prepared as described above using the volatile-free tannin-F, furfuryl alcohol, and water.
• the volatile-free condensed tannin- based foam was prepared as described in Example 2 without using PF resole in 6'x6'x2' mold. The composition, process conditions and foam properties are reported in Table 10.
• Table 10 Composition, process conditions and properties of the bio based condensed tannin-based foam by using pre-heated tannin

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