Degradable absorbent material and manufacturing process therefor

• US 4,931,139 A
• Filed: 12/31/1987
• Issued: 06/05/1990
• Est. Priority Date: 01/02/1987
• Status: Expired due to Term

• Current Assignee: Absorption Corporation
• Original Assignee: Absorption Corporation
• Inventors: Phillips, Christopher R.
• Primary Examiner(s): Bell, James J.
• Application Number:
  US07/236,678
• Time in Patent Office: 887 Days
• Field of Search: 162/100, 162/147, 162/169, 162/189, 162/DIG. 9, 119/1, 210/680, 210/693, 210/924, 428/283, 428/913, 264/118, 264/122, 264/141
• US Class Current: 162/100
• CPC Class Codes: A01K 1/0155 comprising organic material
• CPC Class Codes: C09K 3/32 for absorbing liquids to remove pollution, e.g. oil, gasoline, fat
• CPC Class Codes: Y10S 162/09 Uses for paper making sludge
• CPC Class Codes: Y10S 210/924 using physical agent, e.g. sponge, mop
• CPC Class Codes: Y10S 428/913 Material designed to be responsive to temperature, light, moisture

Abstract

Degradable particulate absorbent materials, together with processes for manufacture thereof, wherein the absorbent materials: (i) have, in most forms of the invention, only on the order of 0% to 10%, by weight, of inorganic solids or "fillers", and in all forms have less than 30% inorganic solids by weight; (ii) are not in pellet form; (iii) are characterized by an open porous fiber structure having relatively low bulk densities on the order of not more than 13 lbs./ft.³ and preferably only from about 6 to about 10 lbs./ft.³ ; (iv) are characterized by high rates of absorption and high absorptive capacities; (v) are highly flammable both before and after absorption of liquid materials which are often themselves non-flammable and, therefore, are characterized by high heat values during recycling; (vi) produce relatively little ash when incinerated, thus minimizing disposal costs and problems; and (vii), readily permit of treatment to render the degradable particulate absorbent materials hydrophobic and/or characterized by their ability to remove, and/or form a barrier for, toxic and/or noxious odorants.

Claims

1. A process for forming a degradable particulate absorbent material having not more than 30% inorganic solids content by weight and comprising the steps of:

a. obtaining waste cellulose fiber material having not more than 30% inorganic solids content by weight with a total dry solids content ranging from approximately 20% to approximately 50% by weight;

b. rehydrating the waste cellulose fiber material to produce a water/fiber slurry comprising on the order of about 96.5% water by weight and about 3.5% total solids by weight;

c. adding a water insoluble latex emulsion to the slurry produced in Step (a) in an amount ranging from about 0.5% to about 5.0% of the total dry solids by weight in the slurry;

d. dewatering the slurry to form a shreddable press cake;

e. particulating the press cake by means of a shredding device to form discrete particles;

f. conditioning the discrete particles produced in Step (e) by imparting a tumbling motion to such particles in the presence of a water mist; and

,

g. drying the conditioned discrete particles to produce a generally flat planar particulate to produce a generally flat planar particulate absorbent medium ranging from 80% total dry solids by weight to 92% total dry solids by weight and having not more than 30% inorganic solids content by weight.

2. The degradable particulate absorbent material prepared by the process of claim 1 having a bulk density of not more than 13 lbs./ft.³.

3. The degradable particulate absorbent material prepared by the process of claim 1 having a bulk density of from approximately 6 lbs./ft.³ to approximately 10 lbs./ft.³.

4. The degradable particulate absorbent material prepared by the process of claim 1 containing not more than 10% by weight of inorganic solids.

5. The degradable particulate absorbent material prepared by the process of claim 1 having an inorganic solids content equal to or as closely approximating 0% by weight as possible.

6. A process for preparing a degradable particulate absorbent material as set forth in claim 1 wherein an acidic material is added to the slurry formed in Step (b) in sufficient quantity to reduce the pH value of the slurry to a level in the range of 4.5 to 5.5.

7. A process for preparing a degradable particulate absorbent material as set forth in claim 6 wherein the acidic material is aluminum sulfate.

8. A process for preparing a degradable particulate absorbent material as set forth in claims 1, 6 or 7 wherein a flocculant is added to the slurry formed in Step (b) prior to the dewatering step set forth in Step (d) and in an amount sufficient to initiate flocculation of the fiber materials in the slurry and to clarify the water contained therein.

9. A process for preparing a degradable particulate absorbent material as set forth in claims 1, 6 or 7 wherein a water soluble surfactant is sprayed upon the discrete particles during conditioning thereof in Step (f) so as to enhance the wetability thereof.

10. A process for preparing a degradable particulate absorbent material as set forth in claim 8 wherein a water soluble surfactant is sprayed upon the discrete particles during conditioning thereof in Step (f) so as to enhance the wetability thereof.

11. A process for preparing a degradable particulate absorbent material as set forth in claims 1, 6 or 7 wherein a water soluble deodorizing agent is applied to the discrete particles during the conditioning step set forth in Step (f).

12. A process for preparing a degradable particulate absorbent material as set forth in claim 8 wherein a water soluble deodorizing agent is applied to the discrete particles during the conditioning step set forth in Step (f).

13. A degradable absorbent material prepared by the process of claim 11 suitable for use as a bedding material during animal air transport.

14. A process for preparing a degradable particulate absorbent material as set forth in claims 1, 6 or 7 wherein a flocculant is added to the slurry formed in Step (b) prior to the dewatering step set forth in Step (d) and in an amount sufficient to initiate flocculation of the fiber materials in the slurry and to clarify the water contained therein, and a water soluble deodorizing agent is applied to the discrete particles during the conditioning step set forh in Step (f).

15. A degradable absorbent material prepared by the process of claim 14 suitable for use as a bedding material during animal air transport.

16. A process for preparing a degradable particulate absorbent material as set forth in claim 1 wherein inorganic solid materials are added to the slurry formed in Step (b) in sufficient quantity to raise the content of total inorganic solids in the slurry to the range of approximately 20% to less than 30% total inorganic solids by weight so as to increase the bulk density of the material to on the order of 13 lbs./ft.³, thereby rendering the material readily flushable.

17. A process for preparing a degradable particulate absorbent material as set forth in claim 16 wherein a water soluble deodorizing agent is applied to the discrete particles during conditioning thereof in Step (f).

18. The particulate degradable absorbent material produced by the process of claims 16 or 17 having a bulk density on the order of 13 lbs./ft.³ and an inorganic solids content in the range of about 20% inorganic solids by weight to less than 30% inorganic solids by weight and suitable for use as a flushable litter material for cats and similar pets.

19. A process for preparing a degradable particulate absorbent material as set forth in claim 1 wherein a water insoluble resin is added to the slurry formed in Step (b) prior to dewatering in Step (d) and in an amount ranging from about 2% of total dry solids by weight to about 4% total dry solids by weight, thereby reducing the total fibrous dry solids content of the slurry to a range of about 90% to about 97.5% dry solids by weight;

and, further including the addition of a water insoluble ionic wax to the slurry prior to dewatering thereof during Step (d), thereby rendering the material hydrophobic.

20. A process for preparing a degradable particulate absorbent material as set forth in claim 19 wherein a non-ionic wax emulsion is applied to the discrete particles during conditioning thereof in Step (f) so as to enhance the hydrophobicity thereof.

21. A process for preparing a degradable particulate absorbent material as set forth in claim 1 wherein a water insoluble liquid plastic material is added to the slurry produced in Step (b) prior to dewatering thereof in Step (d) and in an amount ranging from about 2% total dry solids by weight to about 4% total dry solids by weight, so as to produce a hydrophobic, degradable, particulate absorbent material.

22. The hydrophobic, degradable, particulate absorbent material produced by the process of claims 19, 20 or 21.