Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From reactant having at least one -n=c=x group as well as...
Patent
1997-06-19
2000-06-27
Gorr, Rachel
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
From reactant having at least one -n=c=x group as well as...
25218222, 4284251, 560 26, 560115, 560158, 527301, C08G 1810
Patent
active
060808314
DESCRIPTION:
BRIEF SUMMARY
The invention relates to repulpable cellulose-containing, optionally wood-containing materials which can be prepared using water-dispersible polyisocyanates.
EP-A 0 074 544 describes aqueous dispersions of 1. a concentrated rosin size and 2. hydrophobic ketene dimer or hydrophobic isocyanates having at least 12 C atoms. These dispersions are obtained by using a cationic dispersing agent.
A process for exclusive wet strength treatment of paper with the aid of water-dispersible polyisocyanate mixtures which contain 2 to 20% by weight of ethylene oxide units arranged in the form of polyether chains, these chains having a statistical average of 5 to 70 ethylene oxide units, is also known from DE-A 4 211 480.
EP-A 0 582 166 describes the use of polyisocyanates containing tertiary amino groups and/or ammonium groups and 0 to 30% by weight (based on the mixture) of ethylene oxide units in the form of potyether chains, with the aim of preparing cellulose-containing materials which have been given a dry strength and wet strength treatment and/or have been sized.
All papers produced using polyisocyanates in the pulp or treated using polyisocyanates in the surface have the common feature that, depending on the amount used, they are difficult to repulp or cannot be repulped at all. It is indeed the point of the wet strength treatment of the paper to ensure mechanical strength when the paper is wet through with water; repulpability, for example in water or dilute aqueous alkaline solutions, is therefore in general not possible. On the other hand, recycling of production waste from paper, card and paperboard production (for example edge trimmings, other trimmings and incorrect batches) is expedient and necessary. There is therefore a need for a water-dispersible polyisocyanate which guarantees wet strength as well as dry strength and also has a sizing action, and at the same time imparts repulpability to the cellulose-containing and optionally wood-containing material under the conditions of papermaking.
The invention relates to cellulose-containing, optionally wood-containing materials which have been obtained using water-dispersible polyisocyanates, which are in turn prepared by reaction of the following starting components: ##STR3## in which: R.sup.1 denotes an aliphatic hydrocarbon radical having 2 to 18 carbon atoms; a cycloaliphatic hydrocarbon radical having 4 to 15 carbon atoms; an aromatic hydrocarbon radical having 6 to 15 carbon atoms or an araliphatic hydrocarbon radical having 8 to 15 carbon atoms, atoms and optionally contains double bonds, also be heterocyclic, optionally with inclusion of the ester oxygen or amide nitrogen from X, ##STR4## where R.dbd.H or C.sub.1 -C.sub.4 -alkyl, or a constituent of a cyclic structure, groups, contain ether, ester or amide groups, have at least one functional group which is reactive towards isocyanates and contain at least one tertiary amino group and/or ammonium group.
The invention preferably relates to: obtained using water-dispersible polyisocyanates which in turn have been prepared by using modified polyisocyanates of the formula (II) ##STR5## in which R.sup.1 and R.sup.3 have the abovementioned meanings, atoms and optionally contains at least one double bond, atoms or hydrogen and
Another preferred embodiment are cellulose-containing, optionally wood-containing materials which have been obtained using water-dispersible poly-isocyanates which have in turn been prepared by using modified polyisocyanates of the formula (III): ##STR6## in which R.sup.1 and R.sup.3 have the abovementioned meanings, atoms and/or a radical of the formula (VII) ##STR7## in which R.sup.7 and R.sup.8 represent methyl or hydrogen, but one of the two radicals always denotes hydrogen, and z represents a number from 1 to 5,
The invention furthermore relates to a process for the preparation of water-dispersible polyisocyanates, which is characterized in that the following are reacted with one another in any desired sequence: groups, contain ether, ester or amide groups, have at least one functio
REFERENCES:
patent: 3505001 (1970-04-01), Wagner
patent: 3645942 (1972-02-01), Brown et al.
patent: 3969394 (1976-07-01), Reader
patent: 5503714 (1996-04-01), Reiners et al.
Jansen Bernhard
Konig Joachim
Meyer Rolf-Volker
Reiners Jurgen
Thiele Bernd
Bayer Aktiengesellshaft
Gorr Rachel
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