Catalyst – solid sorbent – or support therefor: product or process – Solid sorbent – Organic
Patent
1999-03-11
2000-11-14
Bell, Mark L.
Catalyst, solid sorbent, or support therefor: product or process
Solid sorbent
Organic
502407, 604364, 604375, B01J 2000, B01J 2010, B01J 2012, A61F 1315, A61F 1320
Patent
active
061470287
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention relates to a surface coated modified starch matrix useful for absorption of malodor. The present invention also relates to methods for absorbing hydrophobic materials from the air or aqueous matrices.
BACKGROUND OF THE INVENTION
The suppression or elimination of odors, particularly undesirable odors, has been the objective of countless investigations. Malodors have their genesis in many forms but those that are of most consequence to human beings are those involving occasional or repeated daily exposure. Of primary concern are those malodors that are caused by normal bodily functions, for example, the urine and feces odors associated with infants and the malodors associated with menses.
Cultural and aesthetic standards have influenced the permissible level of human and environmental malodors and control of these odors has been the focus of investigation for many centuries. In general, these investigations have been focused on either of two approaches, namely: (a) odor masking, in which a substance of strong yet relatively pleasant odor is introduced into the proximity of a less pleasant odor source with the intent of overburdening the olfactory receptors with the dominant pleasant odor, or (b) sequestering the undesired odorous substance in a non-volatile form either by chemical reaction, adsorption or absorption on a sorbent material exhibiting a preference for the odorous substance.
Odor masking, although effective in the short term, has certain limitations. First, masking does not remove or eliminate the source of the malodor. Secondly, when scents and perfumes are used to overcome malodors, the user must make sure an effective and constant level of masking agent is present to avoid too low a level of masking agent that may not be sufficient to cover-up the malodor. In turn, too high a level of masking agent may itself produce an undesirable effect. The premature depletion of the masking agent can be an additional concern.
Sequestration has thus become the method of choice for elimination and control of both human and environmental malodors. The more effective approach has been to sequester the undesired malodor primarily by adsorption.
By far the most commonly employed of the solid adsorbents are activated charcoal or active carbon, although silica gel, activated alumina, kieselguhr, Fullers earth and other clay minerals and zeolites, alone or in combination, have also been proposed as odor "adsorbents". In U.S. Pat. No. 4,437,429, to Goldstein et al., issued Mar. 20, 1984, the use of a hydrated zeolite in admixture with clay is proposed as being particularly useful for the control of odors from pet litter. Though it is observed that the use of zeolites by themselves as litter material has generally been unsuccessful due to their poor water adsorption properties as compared with clays. However, these absorbents are direct to methods of soaking up moisture or liquids whereas, described herein below, the present invention is directed to the absorption of volatile substances without the necessity to absorb any liquid carrier material.
The use by women during menstruation of sanitary napkins, pads, and panty liners has become common place. Although natural fluids produced during menstruation are suitably absorbed by the catamenial absorbent material thereby protecting clothing from damage, the problem of malodor persists. This is due in part to the fact that many chemical compounds responsible for malodor typically have very low odor detection thresholds and are perceptible at the part per million (ppm) level. In addition, may of these malodorous materials are hydrophobic easily partitioning out of the liquid phase as the fluids are absorbed by the catmenial substrate material.
It has now been surprisingly found that modified starch granules can be coated with surface modifying agents producing microporous hydrophobic granules that readily absorb malodorous agents even when the agents are in the "gaseous" state. For example, when menstrual fluid is absorbed
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patent: 5801116 (1998-09-01), Cottrell et al.
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Bamber Jerffrey V.
Bell Mark L.
Echler Rich S.
Hailey Patricia L.
Milbrads Edward J.
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