Biodegradable cellulosic material and process for making such material

• US 5,360,586 A
• Filed: 11/06/1992
• Issued: 11/01/1994
• Est. Priority Date: 11/06/1992
• Status: Expired due to Fees

• Current Assignee: Senniger Powers Leavitt & Roedel (Senniger Powers, LLC)
• Original Assignee: Danny R. Wyatt
• Inventors: Wyatt, Danny R., Wyatt, Everette L.
• Primary Examiner(s): SZEKELY, PETER A
• Application Number:
  US07/972,937
• Time in Patent Office: 725 Days
• Field of Search: 521/84.1, 521/109.1, 106/122, 106/127, 264/53, 264/54, 264/211.23
• US Class Current: 264/54
• CPC Class Codes: B29K 2001/00 Use of cellulose, modified cellulose or cellulose derivatives, e.g. viscose, as moulding material
• CPC Class Codes: B29K 2995/0059 Degradable
• CPC Class Codes: B29L 2031/7132 Bowls, Cups, Glasses
• CPC Class Codes: C08J 2301/02 Cellulose; Modified cellulose
• CPC Class Codes: C08J 9/125 Water, e.g. hydrated salts
• CPC Class Codes: C08L 1/02 Cellulose; Modified cellulose
• CPC Class Codes: C08L 2201/06 Biodegradable
• CPC Class Codes: C08L 2666/02 Organic macromolecular compounds, natural resins, waxes or and bituminous materials

Abstract

A process for making a shaped biodegradable cellulosic article from cellulose-containing material having a water content of less than about 50 percent by weight. The process includes forming a dry mix of the material, a bonding agent and an expander. The dry mix is fed to a screw extruder and pressurized to a nominal pressure in the extruder. Water is injected into the pressurized dry mix. The wetted mixture is then extruded into a shaped article. A biodegradable product is also disclosed herein.

Claims

1. A process for making a shaped biodegradable article from cellulose-containing material, the material having a water content less than about 50 percent by weight, the process comprising:

forming a dry-mix of the cellulose-containing material, a bonding agent and an expander;

feeding the dry mix to an extruder;

pressurizing the dry mix to a pressure above atmospheric pressure in the extruder;

injecting water into the pressurized dry mix; and

extruding the wetted mixture into a shaped article.

2. A process as set forth in claim 1 further comprising the step of drying the extruded mix to a final water content of less than 40 percent by weight.

3. A process as set forth in claim 2 wherein said extruded mix is dried in a convection oven.

4. A process as set forth in claim 1 wherein the extruded mix comprises cellulose material in an amount ranging from about 5 percent to about 90 percent by weight, bonding agent in an amount ranging from about 3 percent to about 90 percent by weight and expander in an amount ranging from about 3 percent to about 80 percent by weight.

5. A process as set forth in claim 1 wherein the extruded mix comprises cellulose material in an amount ranging from about 5 percent to about 80 percent by weight, bonding agent in an amount ranging from about 15 percent to about 80 percent by weight and expander in an amount ranging from about 3 percent to about 50 percent by weight.

6. A process as set forth in claim 1 wherein the extruded mix comprises cellulose material in an amount ranging from about 20 percent to about 60 percent by weight, bonding agent in an amount ranging from about 16 percent to about 45 percent by weight and expander in an amount ranging from about 3 percent to about 30 percent by weight.

7. A process as set forth in claim 1 wherein the dry mix is fed to an extruder having a mixing chamber and two screws.

8. A process as set forth in claim 1 further comprising the step prior to feeding the cellulose to the extruder of reducing the water content of the cellulose to less than approximately 30 percent by weight.

9. A process as set forth in claim 1 further comprising the step prior to feeding the cellulose to the extruder of reducing the water content of the cellulose to less than approximately 25 percent by weight.

10. A process as set forth in claim 1 further comprising the step of blending a fire retardant into the mix.

11. A process as set forth in claim 1 further comprising the step of blending a preservative into the mix.

12. A process as set forth in claim 1 further comprising the step of adding ingredients selected from a group consisting of boron, sodium carbonate, animal glue, carbonated water, cargenin, amino acids, nitrates and lactic acids.

13. A process as set forth in claim 1 wherein the dry mix is pressurized to a pressure above 18 pounds per square inch absolute.