The cellulosic polymers are widely used in the preparation of food, plastics, textiles, pharmaceuticals, and others. Cellulose is the most readily available raw material in the world owing to the fact that it is the chief constituent of nearly all forms of plant life. Cellulose constitutes over 98% of cotton fiber, as much as 50% of most wood fiber and about 35% of cereal straws. Cellulose is a linear homopolymer of anhydroglucose units linked together by .beta.-D-1,4 glycosidic bonds. X-ray diffraction and other evidence indicate that callulose microfibers are partially crystalline and partially amorphous. On the average, the structure of natural cellulose is considered to compose about 15% of amorphous and 85% of crystalline. The degree of polymerization of native cellulose generally ranges from 1,000 to 10,000. Studies of chemical derivatives confirm the existence of one primary hydroxyl group and two secondary hydroxyl groups for each anhydroglucose unit. These hydroxyl groups provide sites for the important chemical reactions of cellulose leading to the preparation of useful products. By chemical modification, a number of functional properties can be introduced in comparatively inexpensive modified cellulose.
The bleaching of cellulose materials with hypochlorites has been known for many years. Primarily bleaching has been employed to remove undesirable color bodies from the cellulose material by utilizing relatively a high pH (ie. about 9 or above) which is maintained throughout the bleach cycle, resulting in a raw cellulose fiber material (i.e. dissolving grade cellulose-DGC) suitable for the production of rayon, paper, etc. The reaction of cellulose with hypochlorites at an uncontrolled pH below 9 has been studied, but no apparent use of the resulting product is known. We have found that the treatment of cellulose materials with appropriate amounts of hypochlorites at a suitable low pH results in a chemically modified cellulose material which is suitable as a carrier vehicle for a wide variety of active, cosmetic, pharmaceutical and the like preparations.
Accordingly, it is the primary object of the present invention to provide a modified cellulose product suitable for use as a carrier vehicle for a wide variety of materials.
A further object of the present invention is to provide a bodying agent composed of a modified cellulose.
Still another object of the present invention is to provide a method for modifying celluose to produce useful carrier vehicles and bodying agents.
These and other objects of the present invention will be more apparent from the discussion which follows.