Mixed tannin-phenolic foams
View Patent ↗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.
1. A foam comprising:
(a) a continuous polymeric phase defining a plurality of cells, wherein:
the continuous polymeric phase comprises a mixed-resin derived from a tannin, furfuryl alcohol, and a phenolic resole, 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, and
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.
2. The foam of claim 1 , wherein the phenol, the tannin, and the first monomer are present in a weight ratio of 1:0.05:0.3 to 1:3:3.
3. The foam of claim 1 , wherein the mixed-resin further comprises a second monomer comprising one or more of acrolein, levulinate esters, sugars, 2,5-furandicarboxylic acid, urea, glycerol, sorbitol, and lignin.
4. The foam of claim 3 , wherein the phenol, urea, and the first monomer are present in a weight ratio of 1:0.05:0.3 to 1:0.008:3.
5. The foam of claim 1 , wherein the open-cell content measured according to ASTM D6226-5, is less than 40%.
6. The foam of claim 1 , wherein the foam has a density in the range of 10-500 kg/m 3 .
7. The foam of claim 1 , 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.
8. The foam of claim 1 , wherein at least one of the one or more blowing agents comprises 1,1,1,4,4,4-hexafluoro-2-butene.
9. The foam of claim 1 , wherein the foam has a thermal conductivity in the range of 0.015-0.050 W/m·K.
10. The foam of claim 1 , wherein the tannin is derived from mimosa, acacia, quebracho, pine, spruce, fir, tanoak, oak, birch, maple, eucalyptus, tara, catechu, or mixtures thereof.
11. The foam of claim 1 , wherein the foam has a limiting oxygen index of at least 23, measured according to ASTM-D2863.
12. The foam of claim 1 , wherein at least one the phenolic resole, the tannin or the mixed-resin comprises an additive.
13. The foam of claim 12 , 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.
14. An article comprising the foam of claim 1 .
15. The article of claim 14 comprising a sandwich panel structure, wherein the sandwich panel structure comprises the foam disposed between two similar or dissimilar non-foam materials.