Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – At least one aryl ring which is part of a fused or bridged...
Reexamination Certificate
1999-03-26
2001-03-13
Niland, Patrick D. (Department: 1714)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
At least one aryl ring which is part of a fused or bridged...
C162S164600, C524S591000, C524S839000, C524S928000, C528S044000, C528S065000, C528S085000
Reexamination Certificate
active
06201060
ABSTRACT:
The invention relates to water-dispersible polyisocyanates and their preparation and use.
DE-A 4 211 480 discloses a process for wet strength treatment of paper with the aid of water-dispersible polyisocyanate mixtures which comprise 2 to 20% by weight of ethylene oxide units arranged in the form of polyether chains, these chains containing a random average of 5 to 70 ethylene oxide units. EP-A 0 582 166 describes the use of polyisocyanates containing tertiary amino groups and/or ammonium groups and 0 30% by weight (based on the mixture) of ethylene oxide units in the form of polyether chains, with the aim of producing cellulosic materials which have been given a dry strength and wet strength treatment and/or have been sized. In Example 20, the use of methylated dimethylaminoethanol is described. DE-A 4 436 058 provides information on a process for the preparation of cellulosic materials which have been given a dry strength and/or wet strength treatment, using water-dispersible polyisocyanates with an increased polyether content.
DE-A 4 446 334.0 describes a process for the preparation of paper which is easier to repulp, using or co-using isocyanates containing ester or amide structures.
In view of the increased requirements, effective paper auxiliaries should be provided in a simplified preparation.
The invention relates to water-dispersible polyisocyanates P obtainable by reaction of the following starting components:
a) at least one polyisocyanate a),
b) at least one polyalkylene oxide polyether alcohol b) optionally containing ester groups and
c) at least one quatemized tertiary aminopolyalkylene oxide polyether alcohol, preferably of the structure (I)
wherein:
n denotes an integer from 2 to 60,
R
1
and R
2
are identical or different and denote an alkyl radical having 2 to 7 C atoms, or together, optionally including R
3
, denote the radical of a heterocyclic ring, in particular morpholine,
R
3
denotes an alkyl radical having 1 to 7 C atoms,
X denotes an anion customary in isocyanate chemistry, in particular
Y and Z denote hydrogen or methyl, with the proviso that always at least one of the two represents hydrogen, it being possible for the recurring units
in each case to be identical or different from one another,
d) optionally further auxiliaries and additives.
The term “water-dispersible” in connection with polyisocyanates P according to the invention means that they are polyisocyanates which, in a concentration of 70% by weight, preferably up to 50% by weight, in water, give finely divided dispersions with particle sizes of less than 500 nm.
In a preferred embodiment, polyisocyanate a) is a modified polyisocyanate.
The term “modified” in connection with the polyisocyanates means generally that they are secondary products, which are known per se, of diisocyanates which are known per se and preferably have at least one of the structural elements mentioned below.
Modified polyisocyanates a) which can be used are: aliphatic, cycloaliphatic, araliphatic or aromatic isocyanates with an NCO functionality of 1.8 to 4.2. Polyisocyanates which contain uretdione and/or isocyanurate and/or allophanate and/or biuret and/or oxadiazine structures and which are accessible in a known manner from aliphatic, cycloaliphatic, araliphatic or aromatic diisocyanates are preferably used.
These are preferably essentially polyisocyanate mixtures which have an NCO content of 19 to 24% by weight, comprise trimeric 1,6-diisocyanatohexane or 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethyl-cyclohexane and the corresponding higher homologues, and contain isocyanurate groups and optionally uretdione groups. The corresponding polyisocyanates of the NCO content mentioned, which are largely free from uretdione groups and contain isocyanate groups, are obtained by catalytic trimerization, which is known per se, of 1,6-diisocyanatohexane or 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethyl-cyclohexane, with formation of isocyanurate, and preferably have an (average) NCO functionality of 3.2 to 4.2 are particularly preferred. The trimeric polyisocyanates which have an NCO content of 19 to 25% by weight, are obtained by reaction of 1,6-diisocyanatohexane with less than the equivalent amount of water in a known manner and essentially contain biuret groups are also preferred.
The polyisocyanates described in DE-A 4 446 334 in claims
1
,
2
,
3
,
7
and
8
can likewise be employed as modified polyisocyanate a). Particularly preferred polyisocyanates of this type have the formulae (II) and (III) given in DE-A 4 446 334.
Preferred polyisocyanates a) correspond to the following formula (II)
in which:
R
4
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,
R
5
denotes an aliphatic hydrocarbon radical which optionally contains double bonds and has 10 to 35 carbon atoms,
R
6
denotes an at least divalent hydrocarbon radical, which can also optionally be heterocyclic, including the ester oxygen or amide nitrogen from X,
X denotes
where R═H or C
1
-C
4
-alkyl or a constituent of a cyclic structure, n denotes a number, at least 2, and y denotes a number, at least 1,
either by themselves or as a mixture with isocyanates which do not contain ester and/or amide groups.
Polyalkylene oxide polyether alcohols b) which optionally contain ester groups are mono- or polyhydric polyalkylene oxide polyether alcohols containing a random average of 2 to 70, preferably 2 to 60 ethylene oxide units per molecule, such as are accessible in a manner known per se by alkoxylation of suitable starter molecules. To prepare these polyalkylene oxide polyether alcohols, any desired mono- or polyhydric alcohols of the molecular weight range 32 to 150 g/mol, such as are also used, for example, according to EP-A 0 206 059, can be employed as starter molecules. Monofunctional aliphatic alcohols having 1 to 4 carbon atoms are preferably used as starter molecules. The use of methanol or ethylene glycol monomethyl ether is particularly preferred. Alkylene oxides which are suitable for the alkoxylation reaction are, in particular, ethylene oxide and propylene oxide, which can be employed in the alkoxylation reaction in any desired sequence or also as a mixture.
The polyalkylene oxide polyether alcohols are preferably pure polyethylene oxide polyethers or mixed polyalkylene oxide polyethers which contain at least one polyether sequence which has at least 2, in general 2 to 70, preferably 2 to 60, and particularly preferably 2 to 50 ethylene oxide units, the alkylene oxide units of which consist of ethylene oxide units to the extent of at least 60 mol %, preferably to the extent of at least 70 mol %. Preferred such polyalkylene oxide polyether alcohols are monofunctional polyalkylene oxide polyethers which are started from an aliphatic alcohol containing 1 to 4 carbon atoms and contain a random average of 2 to 60 ethylene oxide units. Particularly preferred polyalkylene oxide polyether alcohols are pure polyethylene glycol monomethyl ether alcohols which contain a random average of 2 to 40 ethylene oxide units.
Suitable polyalkylene oxide polyethers containing ester groups are OH-terminated polyester ethers which are obtainable by reaction of aliphatic C
2
-C
8
-dicarboxylic acids or esters or acid chlorides thereof with polyethers from the group consisting of polyethylene oxides, polypropylene oxides or mixtures thereof or mixed polyethers therefrom, 0.8 to 0.99 equivalent of carboxyl groups or derivatives thereof being employed per OH equivalent of the polyether, and have an average molecular weight of less than 10,000 g/mol, preferably less than 3000 g/mol, and have hydroxyl end groups.
Quaternized aminopolyalkylene oxide polyether alcohols are known per se from EP-A-109 354 and EP-A-335 115.
The quaternized tertiary aminopolyalkylene oxide polyether alcohols I are preferably prepared by using alcohols of the molecular weight range
Jansen Bernhard
Kijlstra Johan
Roick Thomas
Thiele Bernd
Bayer Aktiengesellschaft
Gil Joseph C.
Henderson Richard E. L.
Niland Patrick D.
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