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US 6,548,730 B1Granted
Wound dressings and materials suitable for use therein
AssigneeAcordis Speciality Fibres Limited
InventorsChampa Patel, Roger Bray
Life of this patent
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AssigneeAcordis Speciality Fibres Limited
InventorsChampa Patel, Roger Bray
Estimating the term…
Carboxymethylated cellulosic articles having degree of substitution in the range from 0.12 to 0.35 and in which the carboxymethyl groups are believed to be predominantly within the amorphous regions to the exclusion of the crystalline regions have usefully non-adherent properties as wound dressings. Such wound dressings may be made by carboxymethylating a cellulose fabric so that its absorbency is little greater after carboxymethylation than beforehand and the degree of substitution is as stated above. Carboxymethylation can be carried out by contacting cellulose II fibers or other articles with a solution containing sodium hydroxide, sodium chloroacetate, water and ethanol. The solution may contain from 4 to 8 percent by weight sodium hydroxide and from 50 to 60 percent by weight water (including water in the fibre) or the weight ratio of sodium hydroxide to water (including water in the article) may be from 0.095 to 0.115 and the weight ratio of cellulose in the article to water (including water in the article) may be from 0.22 to 0.28.
A method of manufacturing a carboxymethylated fibre of cellulose II, comprising the step of contacting a fibre of cellulose II with a solution for carboxymethylation purposes, said solution containing from 4 to 8 percent by weight sodium hydroxide, sodium chloracetate, from 50 to 60 percent by weight water, and the balance ethanol, such that the carboxymethylated fibre of cellulose II obtained as a result of said contacting step has an average degree of substitution of cellulose by carboxymethyl groups measured by IR spectroscopy in the range from 0.12 to 0.35.
A carboxymethylated cellulose article having an average degree of substitution of cellulose groups by carboxymethyl groups, measured by IR spectroscopy, in the range from 0.12 to 0.35 and having a degree of crystallinity, measured by NMR spectroscopy, in the range from 10 to 70 percent.
A method of manufacturing a carboxymethylated cellulose article comprising the step of contacting an article of cellulose II with a solution for carboxymethylation purposes, said solution containing sodium hydroxide, sodium chloracetate, ethanol and water, in which the weight ratio of sodium hydroxide to water is in the range from 0.095 to 0.115, and the weight ratio of cellulose to water is in the range from 0.22 to 0.28, such that the carboxymethylated cellulose article obtained as a result of said contacting step has an average degree of substitution of cellulose groups by carboxymethyl groups, measured by IR spectroscopy, in a range from 0.12 to 0.35 and a degree of crystallinity, measured by NMR spectroscopy, in a range from 10 to 70 percent.
A wound dressing made by a process comprising the steps of:
A wound dressing made by a method comprising the steps of:
Dependencies are inferred from the claim text.