Compositions: coating or plastic – Coating or plastic compositions – Metal-depositing composition or substrate-sensitizing...
Patent
1991-07-12
1993-03-30
Dixon, Jr., William R.
Compositions: coating or plastic
Coating or plastic compositions
Metal-depositing composition or substrate-sensitizing...
106 27R, C09D 1106
Patent
active
051980240
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to a printing ink, particularly to a newsprint ink, essentially including pigment and binder components.
Particularly newsprint covers a considerable part of the current consumption of paper. In terms of national economy it is naturally advisable to use recycled fibre at least partially in the production of newsprint. Recycled fibre is obtained from waste paper subjected to a deinking process for removing previous printing ink and soil. Waste paper is decomposed in the deinking process by a vigorous agitation in the presence of chemicals. The printing ink particles thus removed are separated at the flotation stage of a deinking process. It is obvious that the qualities, particularly whiteness and yield of the recycled fibres obtained from a deinking process are dependent on how effectively the printing ink can be detached from recycled fibres. It is also obvious that the degree of removal of printing ink from waste paper has an effect on the feasibility of the actual deinking process as well as on its enviromental impact.
The currently available types of printing ink, which are applicable to offset, flexo, gravure, silk screen and letterpress printing techniques, are identical in their basic composition. They essentially include pigment and binder components. In most practical cases, the actual binder and a solvent are also separated from each other. In any case, it should be noted that the binder component of the currently employed printing inks includes as its major constituents a resin component as well as a solvent component, particularly a vegetable oil and/or a mineral oil. A characterizing feature in all these printing inks is that the deinking thereof is relatively simple in fresh state. However, especially the recovery of newsprint with all its collection stages e.g. from households to a deinking plant with intermediate storages therebetween leads to the fact that the paper arriving at a deinking plant is in most cases several months old. The performed tests have indicated that all available printing inks, which contain vegetable oils and/or mineral oils, are difficult to deink in aged state. It has been discovered that the problems are due to the chemical changes of a binder as well as to a change in the composition of a printing ink during the aging period caused by the collection process. The following individual reasons can be pointed out: polymerized products from fibres is difficult, remaining resinaceous paste from fibre has proved difficult, of paper and cannot be removed by deinking.
It should further be noted that, due to the aromatic hydrocarbon chains contained therein, most mineral oils cause health hazards which should be observed in carrying out a deinking process and which, thus, incur costs. Also in terms of a deinking process, the mineral oils are especially troublesome since, in order to fulfil the requirements of environmental protection, the deinking process must include an effective purification of the process waste water, the mineral oils being the most problematic factor in view of waste water purification. It has been surprisingly discovered in this invention that the above problems can be overcome by means of a printing ink which is mainly characterized in that the entire binder component comprises a tall oil based substance. In this context, the term tall oil refers to a side product obtained from pulp cooking and consisting of wood extract. This so-called raw tall oil (CTO) produced as a pulp cooking side product comprises a combination that contains resin acids, fatty acids as well as neutral agents. Various distillation processes can be used for separating from raw tall oil (CTO) a plurality of different resin acid mixtures (TOR) and fatty acid mixtures (TOFA) which contain varying amounts of resin acids, fatty acids and neutral agents. These mixtures can be further processed into a chemical form suitable for use as a printing ink binder and/or binder component e.g. by polymerization, esterification, fortification and/or phenolation or a
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Chemical Abstracts, vol. 107, No. 22, 30 Nov. 1987 (Col., OH US), see p. 122, Abstract 200636b, & JP, 6222873 ((Taniguchi Ink Mdg. Col, Ltd.)) 1987.
Sjostedt Markku
Tuovinen Juhani
Dixon Jr. William R.
Einsmann Margaret
Yhtyneet Paperitehtaat Oy
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