1. Field of the Invention
This invention relates to the deinking of waste paper. More particularly, it relates to a novel composition and process for the deinking of waste paper, including difficult-to-deink paper.
2. Description of the Prior Art
The recycling and reuse of waste paper is an important environmental aspect of the enormous and continually growing use of paper in nearly all aspects of modern business and social activities. This conversion of waste paper to fibrous material, advantageously of a quality essentially equivalent to virgin pulp, involves what is generally known in the art as "deinking". In conventional deinking operations, printed, colored and coated paper is generally treated with hot, alkaline, aqueous solutions generally containing a variety of additives, such as detergents, emulsifiers, dispersants and the like. Such operations are reasonably satisfactory in the deinking of paper that is practically free of the variety of synthetic thermoplastic and elastomeric substances now increasingly used in printing inks, functional coatings, laminates, adhesives, etc. The conventional deinking compositions are not suitable, however, for the acceptable deinking of so-called difficult-to-deink grade materials, namely those waste paper materials having such synthetic thermoplastic and elastomeric substances associated therewith as is increasingly the case with respect to the inks, coatings, laminates, adhesives and the like increasingly used in wide varieties of modern paper applications.
The failure to adequately remove the various contaminating substances associated with difficult-to-deink grade waste paper results in their build-up in the paper making system in which the recycled material is being incorporated, thereby causing costly and time-consuming breaks on the paper-making machine and the production of non-saleable paper of substandard quality, i.e., so-called "broke". As a result, the deinking of waste paper by conventional techniques is frequently confined to waste paper not having such synthetic, thermoplastic and elastomeric substances thereon that can not be effectively removed by conventional deinking compositions and techniques. As a result, the lower quality, more difficult-to-deink grade waste papers are not generally reprocessed, despite their generally less expensive nature and the ever growing need for the processing of such waste on the basis of both commercial and environmental consideration.
It is an object of the present invention, therefore, to provide an improved process and composition for the deinking of waste paper.
It is another object of the invention to provide an improved process and composition of particular utility with respect to the deinking of difficult-to-deink grade material.
It is another object of the invention to provide a process and composition for the effective removal of synthetic thermoplastic and elastomeric substances from the waste paper being treated.
With these and other objects in mind, the invention is hereinafter set forth in detail, the novel features thereof being particularly pointed out in the appended claims.
USPTO Backgrounds
USPTO Backgrounds