Water-absorbing material and uses thereof
A chromogenic absorbent material for detecting a detectable substance in a water-containing medium, such as animal urine, is provided. The detectable substance may be indicative of a disease or condition, and the water-containing medium may be an excretion, blood, plasma, an aqueous solution or a solid impregnated with an aqueous solution. The chromogenic absorbent material may include a trigger agent, a chromogenic indicator convertible into a chromogenically active substance in the presence of the trigger agent and the detectable substance, and an absorptive material which is porous, for absorbing the water-containing medium. The absorptive material may include a water-absorbing polysaccharide providing absorptive properties to the chromogenic absorbent material. The trigger agent, the chromogenic indicator and the detectable substance are preferably unreactive to the absorptive material.
1. A process for manufacturing a chromogenic absorbent material for detecting blood, comprising:
providing an absorptive powder onto a surface, thereby obtaining a powder bed, the absorptive powder comprising:
between about 35 wt % and 65 wt % of a water-absorbing polysaccharide, the water-absorbing polysaccharide being a glass-like polysaccharide; and
between about 35 wt % and 65 wt % of a crystalline polysaccharide, the crystalline polysaccharide being less water-absorbent than the water-absorbing polysaccharide;
releasing a chromogenic aqueous solution as discrete drops onto the powder bed to form a solution-impregnated humid material, the chromogenic aqueous solution comprising:
an oxidizing agent responsive to peroxidatic/pseudoperoxidatic activity; and
a chromogenic indicator oxidizable into a colored and/or fluorescent substance in the presence of the oxidizing agent and blood;
maintaining the solution-impregnated humid material supported by the surface in substantially shear-less conditions, until the solution-impregnated humid material agglomerates to form agglomerated humid particles;
drying the agglomerated humid particles, thereby obtaining dried agglomerated particles; and
reducing a particle size of the dried agglomerated particles by grinding and/or sieving.
2. The process of claim 1 , wherein the glass-like polysaccharide comprises pregelatinized starch.
3. The process of claim 1 , wherein the crystalline polysaccharide comprises microcrystalline cellulose (MCC), nanocrystalline cellulose (NCC) or a mixture thereof.
4. The process of claim 1 , wherein the absorptive powder further comprises up to about 3 wt % of a superabsorbent polymer (SAP).
5. The process of claim 4 , wherein the SAP comprises a poly(acrylic acid), a poly(methacrylic acid), a salt thereof, or a mixture thereof.
6. The process of claim 4 , wherein the SAP comprises sodium polyacrylate.
7. The process of claim 1 , wherein the oxidizing agent is a hydroperoxide or a hydroperoxide precursor.
8. The process of claim 1 , wherein the chromogenic indicator comprises a benzidine-type compound.
9. The process of claim 1 , wherein reducing the particle size of the dried agglomerated particles comprises:
grinding the dried agglomerated particles to obtain a ground agglomerated material; and
sieving the ground agglomerated material to obtain a sieved agglomerated material.
10. The process of claim 9 , wherein the sieved agglomerated material has a particle size between 100 mesh and 12 mesh.
11. The process of claim 9 , wherein the sieved agglomerated material has a particle size between 60 mesh and 8 mesh.
12. The process of claim 9 , wherein the grinding is performed using at least one of a belt grinder, a bench grinder, a cylindrical grinder, a surface grinder, a tool grinder, a jig grinder, a gear grinder and a die grinder.
13. The process of claim 9 , further comprising incorporating the sieved agglomerated material into a diaper or a puppy pad.
14. The process of claim 13 , wherein the sieved agglomerated material is incorporated between layers of the diaper or the puppy pad.
15. The process of claim 1 , wherein the surface is substantially planar.
16. The process of claim 1 , wherein the surface extends substantially horizontally.
17. The process of claim 1 , wherein the chromogenic aqueous solution is released from a solution dispenser disposed above the surface, the process further comprising displacing the solution-impregnated humid material away from the solution dispenser.
18. The process of claim 17 , wherein the powder bed is in translation relative to the solution dispenser.
19. The process of claim 1 , further comprising controlling a thickness of the powder bed between about 1 cm and about 5 cm.
20. The process of claim 1 , wherein the drying comprises at least one of drying under vacuum and drying by heating.