Mixed tannin-phenolic foams

Abstract

Disclosed are foam compositions and processes to form mixed tannin-phenolic foams. The foams comprises a continuous polymeric phase defining a plurality of cells, wherein the continuous polymeric phase comprises a mixed-resin derived from a phenol, a tannin, and a first monomer, and wherein the plurality of cells comprises a plurality of open-cells and a plurality of closed-cells with an open-cell content measured according to ASTM D6226-5, of less than 50%. The foam composition also comprises a discontinuous phase disposed in at least a portion of the plurality of closed-cells, the discontinuous phase comprising one or more blowing agents.

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         16 . A process comprising:
 a) forming a mixed-resin by adding a tannin as a co-reactant to a reaction mixture comprising a phenol and a first monomer or a phenolic resole at a temperature in the range of 70-95° C., such that the phenol, the tannin, and the first monomer are present in a weight ratio in the range of 1:0.05:0.3 to 1:3:3
 wherein the first monomer comprises one or more of formaldehyde, paraformaldehyde, furfural, glyoxal, acetaldehyde, 5-hydroxymethylfurfural, 5-furandicarboxylic aldehyde, and difurfural; 
   b) adding 5-30% by weight of one or more blowing agents to 30-90% by weight of the mixed-resin to form a pre-foam mixture;   c) adding 5-30% by weight of an acid catalyst to the pre-foam mixture to form a foam composition;   d) adding 0.5-10% by weight of a surfactant to at least one of the steps (a) or (b), wherein the amounts in %, by weight are based on the total weight of the pre-foam mixture; and   e) processing the foam composition to form a foam, wherein the foam comprises an open-cell content measured according to ASTM D2856, of less than 50%.   
     
     
         17 . The process of  claim 16 , wherein the step of adding a tannin as a co-reactant to the reaction mixture comprises providing a residence time to effectively dissolve the tannin in the reaction mixture comprising a phenol and a first monomer. 
     
     
         18 . The process of  claim 16 , wherein the step of adding a tannin as a co-reactant to the reaction mixture comprises first mixing the tannin with one or more of the first monomer and a second monomer before adding the tannin to the reaction mixture, wherein the second monomer comprises one or more of acrolein, levulinate esters, sugars, 2,5-furandicarboxylic acid, urea, furfuryl alcohol, glycerol, sorbitol, and lignin. 
     
     
         19 . The process of  claim 16 , wherein the step of adding a tannin as a co-reactant to the reaction mixture comprises adding the tannin to the reaction mixture in the absence of a second monomer, wherein the second monomer comprises one or more of acrolein, levulinate esters, sugars, 2,5-furandicarboxylic acid, urea, furfuryl alcohol, glycerol, sorbitol, and lignin. 
     
     
         20 . The process of  claim 16 , wherein the step of forming a mixed resin further comprises:
 (a) adjusting the pH of the reaction mixture comprising a phenol, a first monomer, and a tannin;   (b) heating the reaction mixture to a temperature in the range of 70-95° C.;   (c) keeping the temperature of the reaction mixture constant in the range of 70-95° C.; and   (d) cooling the reaction mixture to room temperature and adjusting the pH to be in the range of 6-8.   
     
     
         21 . The process of  claim 16 , further comprising removing volatiles from the mixed-resin before the step of mixing the mixed-resin with one or more blowing agents. 
     
     
         22 . The process of  claim 16 , wherein the step of processing the foam composition further comprises foaming the foam composition in a closed mold. 
     
     
         23 . The process of  claim 22 , wherein the step of processing the foam composition comprises curing the foam at a temperature in the range of room temperature and 90° C. 
     
     
         24 . The process of  claim 16  further comprises disposing the foam between two similar or dissimilar non-foam materials, also called facers to form a sandwich panel structure. 
     
     
         25 . The process of  claim 16 , wherein the acid catalyst comprises para-toluenesulphonic acid and xylenesulphonic acid in a weight ratio in the range of 0.67:1 to 9:1. 
     
     
         26 . The process of  claim 16 , wherein at least one of the one or more blowing agents has a gas phase thermal conductivity of less than or equal to 0.016 W/m·K at 25° C. 
     
     
         27 . The process of  claim 16  further comprising adding an additive to at least one of the phenolic resole, the tannin, the mixed-resin or the pre-foam mixture, wherein the additive comprises 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 (AlO.OH), zirconium oxide, a polyester polyol, or mixtures thereof. 
     
     
         28 . A foam formed by the process of  claim 16 . 
     
     
         29 . A foam comprising:
 (a) a continuous polymeric phase defining a plurality of cells, wherein:
 i. the continuous polymeric phase comprises a mixed-resin derived from a phenolic resole and a tannin as a co-reactant without use of furfuryl alcohol,
 wherein the phenolic resole is derived from a phenol and one or more of formaldehyde, paraformaldehyde, furfural, glyoxal, acetaldehyde, 5-hydroxymethylfurfural, 5-furandicarboxylic aldehyde, and difurfural (DFF) as a first monomer, 
 
 ii. the plurality of cells comprises a plurality of open-cells and a plurality of closed-cells with an open-cell content measured according to ASTM D2856, of less than 50%; and 
   b) one or more blowing agents disposed in at least a portion of the plurality of closed-cells.   
     
     
         29 ) The foam of  claim 29 , wherein the foam has a density in the range of 10-500 kg/m 3 . 
     
     
         30 ) The foam of  claim 29 , wherein at least one of the one or more blowing agents has a gas phase thermal conductivity of less than or equal to 0.016 W/m·K at 25° C. 
     
     
         31 ) The foam of  claim 29 , wherein the foam has a thermal conductivity in the range of 0.015-0.050 W/m·K. 
     
     
         32 ) The foam of  claim 29 , wherein at least one the phenolic resole, the tannin or the mixed-resin comprises an additive, wherein the additive comprises 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 (AlO.OH), zirconium oxide, a polyester polyol, or mixtures thereof. 
     
     
         33 ) An article comprising the foam of  claim 29 . 
     
     
         34 ) The article of  claim 33  comprising a sandwich panel structure, wherein the sandwich panel structure comprises the foam disposed between two similar or dissimilar non-foam materials.