Biodegradable compositions and articles made from cellulose acetate

Abstract

A foamable composition comprising at least one cellulose acetate, a plasticizer, a nucleating agent, and either a chemical blowing agent or a physical blowing agent is disclosed. The composition is formed into foamed articles that are biodegradable.

What we claim is: 
     
         1 . A foamable composition comprising:
 (1) a cellulose acetate having a degree of substitution of acetyl (DS Ac ) between 2.2 to 2.6;   (2) 5 to 40 wt % of a plasticizer;   (3) 0.1 to 3 wt % of a nucleating agent; and   (4) 0.1 to 15 wt % of a physical blowing agent,   
       wherein the proportions of the cellulose acetate, plasticizer, nucleating agent and physical blowing agent are based on the total weight of the foamable composition. 
     
     
         2 . The foamable compositions of  claim 1 , wherein the physical blowing agent is present at from 1 to 15 wt %. 
     
     
         3 . The foamable composition of  claim 1 , wherein the physical blowing agent comprises CO 2 , N 2 , unbranched or branched (C 2-6 ) alkane, or any combination thereof. 
     
     
         4 . The foamable composition of  claim 1 , wherein the plasticizer comprises triacetin, triethyl citrate, or PEG400. 
     
     
         5 . The foamable composition of  claim 1 , wherein the nucleating agent comprises a particulate composition with a median particle size less than 2 microns. 
     
     
         6 . The foamable composition of  claim 1  wherein the nucleating agent comprises a magnesium silicate, a silicon dioxide, a magnesium oxide, or combinations thereof. 
     
     
         7 . The foamable composition of  claim 1  wherein the foamable composition further comprises a biodegradable fiber. 
     
     
         8 . The foamable composition of  claim 7  wherein the biodegradable fiber comprises hemp, bast, jute, flax, ramie, kenaf, sisal, bamboo, or wood cellulose fibers. 
     
     
         9 . The foamable composition of  claim 1 , wherein the foamable composition is biodegradable. 
     
     
         10 . The foamable composition of  claim 1 , wherein the foamable composition comprises two or more cellulose acetates having different degrees of substitution of acetyl. 
     
     
         11 . The foamable composition of  claim 1 , wherein the foamable composition further comprises a biodegradable polymer that is different than the cellulose acetate. 
     
     
         12 . An article prepared from the foamable composition of  claim 1 , wherein the article is a foam. 
     
     
         13 . The article of  claim 12 , wherein the article has a thickness of up to 6 mm. 
     
     
         14 . The article of  claim 12 , wherein the article has one or more skin layers. 
     
     
         15 . The article of  claim 12 , wherein the article is biodegradable. 
     
     
         16 . The article of  claim 12 , wherein the article has a density less than 0.9 g/cm 3 . 
     
     
         17 . The article of  claim 12 , wherein the article is industrial compostable or home compostable. 
     
     
         18 . The article of  claim 17 , wherein the thickness is less than 3 mm. 
     
     
         19 . The article of  claim 12 , wherein the article exhibits greater than 90% disintegration after 12 weeks according to disintegration test protocol for films, as described in the specification.