Paper making and fiber liberation – Processes of chemical liberation – recovery or purification... – Waste paper or textile waste
Reexamination Certificate
1999-10-08
2001-10-23
Nguyen, Dean T. (Department: 1731)
Paper making and fiber liberation
Processes of chemical liberation, recovery or purification...
Waste paper or textile waste
Reexamination Certificate
active
06306250
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to a process for removing capsule oils from carbonless copy paper in the presence of nonionic surfactants as additive. The invention also relates to the use of these nonionic surfactants for removing capsule oils from carbonless copy paper.
Wastepaper is now being increasingly used for the manufacture of, for example, newsprint and sanitary paper. A special type of wastepaper is so-called carbonless copy paper. Carbonless copy papers contain microcapsules in which dye precursors and so-called capsule oils are present. The function of these capsule oils is to dissolve and/or disperse the dye precursors present in the microcapsules. Now, in the remanufacture of carbonless copy paper, the microcapsules are destroyed by the mechanical stressing the paper undergoes during the slushing step so that the capsule oil is released.
The remanufacture of carbonless copy paper is normally carried out in two steps. The first step is compulsory, the second optional.
The first step in the remanufacture of carbonless copy paper, so called disintegration, may be described as follows: disintegration is generally understood by the expert to be the process of defibration of wastepaper—in the present case the defibration of carbonless copy paper. This process may be induced, for example, in aqueous medium by the application of mechanical energy, for example by stirring. In the case of carbonless copy paper, defibration is accompanied by substantial destruction of the microcapsules present in the paper, the capsule oils they contain being released.
In the second step of the remanufacturing process, the stock suspension is washed and/or subjected to flotation.
If the remanufacturing process mentioned is carried out in the absence of special additives, studies conducted by applicants have shown that around 86% of the capsule oils are removed without washing and/or flotation and that around 94% are removed where washing and/or flotation is/are carried out.
Like other office and administration papers, carbonless copy papers are increasingly entering the recycling circuit. For hygienic and functional reasons, it is desirable in this regard to remove as much of the capsule oil present in the microcapsule coating of the carbonless copy papers as possible during the recycling of fibers from these wastepapers. This prevents, for example, unwanted discoloration of the recycled fibers and the transfer of capsule oils from papers produced using these fibers to foods packed therein. This is very important in particular when the oils used in the carbonless copy papers are aromatic and/or paraffinic, for example alkylated napthalenes, alkylated biphenyls or hydrogenated oils based on mineral oils.
DESCRIPTION OF THE INVENTION
The problem addressed by the present invention was to provide a process for removal capsules oils from carbonless copy paper which would be distinguished by an improved removal of capsule oils. More particularly, the removal of capsule oils in the remanufacture of carbonless copy papers would amount to at least 90%.
It has now surprisingly been found that the problem stated above is elegantly solved if nonionic surfactants (nonionics) are used as additive in the remanufacture of carbonless copy paper. Products of the addition of ethylene oxide and/or propylene oxide onto alcohols containing 8 to 24 carbon atoms have proved to be particularly suitable.
In a first embodiment, therefore, the present invention relates to a process for removing capsule oils from carbonless copy paper in which carbonless copy paper is disintegrated to form a stock suspension which is optionally washed and/or subjected to flotation, characterized in that disintegration and/or washing and/or flotation is/are carried out in the presence of at least one additive selected from the group of nonionic surfactants (nonionics).
Basically, the type of nonionic surfactant used is not critical. In principle, therefore, any nonionics relevantly known to the expert may be used in the process according to the invention. However, one particularly important embodiment of the invention is characterized by the use of addition products of ethylene oxide (EO) and/or propylene oxide (PO) with alcohols containing 8 to 24 carbon atoms. These addition products may be pure EO adducts (alcohol ethoxylates), pure PO adducts (alcohol propoxylates), EO/PO adducts or mixtures of the species mentioned.
In the case of the alcohol ethoxylates, the proportion of EO in the molecule should be on average 2 to 20 mol per mol of alcohol. So far as the alcohol propoxylates are concerned, the proportion of PO in the molecule should be on average 2 to 20 mol per mol of alcohol.
In the case of the EO/PO adducts,
a) the sum of EO and PO should be on average 2 to 20 mol per mol of alcohol and
b) EO and PO should be present in the adducts in molar ratios of 1:10 to 10:1.
So far as the chain length of the alcohols on which the EO and/or PO adducts mentioned are based is concerned, particularly good results are obtained when fatty alcohols with chain lengths of 12 to 18 carbon atoms are used.
In one preferred embodiment of the present invention, fatty alcohol ethoxylates are used as additives either individually or in the form of a mixture. The fatty alcohols on which the EO and/or PO adducts are based are preferably selected so that they essentially contain 12 to 14 carbon atoms.
The additive is normally used in a quantity of 0.1 to 5% by weight, based on the input of paper to be remanufactured. However, smaller or larger quantities of additive may also be used in individual cases at the discretion of the expert. This will largely depend on the type and quantity of oil to be removed, by the type of carbonless copy paper and by the stock consistency in the pulper and during washing.
REFERENCES:
patent: 3933578 (1976-01-01), Kazugai et al.
patent: 4162186 (1979-07-01), Wood et al.
patent: 5259969 (1993-11-01), Srivatsa et al.
patent: 5632857 (1997-05-01), Larson
patent: 0 050 494 (1982-04-01), None
patent: 0 717 144 (1996-06-01), None
M. Saendig, “Handbuch der Papier und Pappenfabrikation” Second Edition vol. 1, Niederwalluf (1971) p. 1484.
Baumgarten Dieter
Heinen Sabine
Hilterhaus Bodo
Hornfeck Klaus
Nellessen Bernhard
Nguyen Dean T.
Nopco Paper Technology Holding AS
Young & Thompsn
LandOfFree
Method of removing capsule oils from self-copying paper does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method of removing capsule oils from self-copying paper, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method of removing capsule oils from self-copying paper will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2561730