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...
Reexamination Certificate
2000-08-30
2001-10-30
Gorr, Rachel (Department: 1711)
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...
C252S182220, C156S307100, C527S301000, C162S164600, C560S026000, C560S115000, C560S158000
Reexamination Certificate
active
06310172
ABSTRACT:
The present invention relates to water-dispersible polyisocyanates, their preparation and their use for producing repulpable cellulose-containing materials.
The prior art has already disclosed a large number of paper auxiliaries based on polyisocyanates. Thus, for example, in EP-A 0 582 166, where, in addition to sizing, the treatment of paper to impart wet strength and dry strength by means of polyisocyanates which have tertiary amino and/or ammonium groups and comprise 0 to 30% by weight (based on the mixture) of ethylene oxide groups in the form of polyether chains is described.
However, the common feature of all papers produced using polyisocyanates in the pulp or treated in the surface is that, depending on the amount used, they can be repulped only with difficulty or not at all. Indeed, the point of the treatment of the paper to impart wet strength is to ensure mechanical strength on wetting with water; repulpability, for example in water or dilute, aqueous alkaline solutions, is therefore generally not possible. On the other hand, the recycling of broke from paper, cardboard and board production (e.g. deckle trim, other waste and off-spec batches) is expedient and necessary. There is therefore a demand for water-dispersible polyisocyanates which ensure wet strength and dry strength but which simultaneously impart to the cellulose-containing material repulpability under the conditions of papermaking.
WO 96/20309 has already disclosed repulpable cellulose-containing materials which can be produced using polyisocyanates containing ester groups.
The non-prior-published German Patent Application No. 196 40 205.0 describes water-dispersible polyisocyanates which are prepared using quatemized tertiary aminopolyalkylene oxide polyether alcohols, which are used as paper auxiliaries having improved absorptive capacity and likewise promise repulpability.
However, the increased requirements of the paper auxiliaries market include not only very good wet strength combined with good repulpability of the paper treated to impart wet strength, but also good water absorption, i.e. good absorptivity of the paper, which is important for many applications. In this respect, the paper auxiliaries known from the prior art are still in need of improvement.
The present invention relates to water-dispersible polyisocyanates, obtainable by reaction of:
a) at least one bishydroxy-functional compound of the structure (I):
HO—R
1
—[O—CR
2
R
3
—O—R
1
]
n
—OH (I)
in which
R
1
represents an alkylene radical having two to ten carbon atoms or represents a radical —R—[O—R]
p
—, R representing an alkylene radical having two to ten carbon atoms and p representing an integer from 0 to 12,
R
2
and R
3
, independently of one another, represent C
1
-to C
10
-alkyl or hydrogen, with the proviso that, if one of the radicals R
2
or R
3
represents hydrogen, the other radical represents C
1
-to C
10
-alkyl, and
n represents an integer from 1 to 45, preferably from 1 to 30, with
b) at least one polyisocyanate of the structure (II)
Q[NCO]
q
(II)
in which
q represents a number greater than or equal to 2 and
Q represents an aliphatic hydrocarbon radical having 2 to 18, preferably 6 to 10, C atoms, a cycloaliphatic hydrocarbon radical having 4 to 15, preferably 5 to 10, C atoms, an aromatic hydrocarbon radical having 6 to 15, preferably 6 to 13, C atoms or an araliphatic hydrocarbon radical having 8 to 15, preferably 8 to 12, C atoms, said aliphatic, cycloaliphatic, aromatic and araliphatic hydrocarbon radicals each optionally containing one or more, preferably 1 to 4, heteroatoms from the series O, N, S,
and subsequent reaction, in any order, with
c) at least one monofunctional polyether alcohol of the structure (III)
R
4
—[O—R
5
]
m
—O—H (III)
in which
R
4
represents C
1
-C
4
-alkyl,
R
5
represents —CHX—CHY—, X and Y representing methyl, ethyl or hydrogen, with the proviso that, if one of the substituents X and Y denotes methyl or ethyl, the other always denotes hydrogen,
m represents an integer between 3 and 50, preferably between 3 and 25, and optionally
d) with a compound of the structure (IV)
H—O—[R
5
—O]
0
—N
+
R
6
R
7
R
8
X
−
(IV)
in which
R
5
has the meaning stated above for formula (III),
R
6
and R
7
, independently of one another, represent C
2
-C
7
-alkyl or
R
6
and R
7
, together with the N atom to which they are bonded, represent a 5- or 6-membered heterocyclic ring, preferably morpholine,
R
8
represents C
1
-C
7
-alkyl,
0 represents an integer from 2 to 60, preferably from 2 to 30, and
X
−
represents an anion, in particular halide, tosyl, trifluoromethylsulphate, methylsulphate, sulphate.
The present invention furthermore relates to a process for the preparation of waterdispersible polyisocyanates by reaction of
a) at least one bishydroxy-functional compound of the abovementioned structure (I) with
b) at least one polyisocyanate of the abovementioned structure (II) and subsequent reaction, in any desired order, with
c) at least one polyether alcohol of the abovementioned structure (III) and optionally with
d) at least one quatemized tertiary aminopolyether alcohol of the abovementioned structure (IV).
In the process according to the invention, optionally further auxiliaries and additives such as, for example, catalyzers or stabilizers for water-dispersible polyisocyanate formulations, known per se in polyurethane chemistry, and viscosity-reducing additives, such as solvents not reactive towards isocyanates, can be concomitantly used. Propylene glycol diacetate and methoxypropyl acetate may be mentioned by way of example for these “diluents”.
The bishydroxy-functional compounds of the structure (I) are obtainable from the dialkyl ketals of ketones or dialkyl acetals of aldehydes. Among all dialkyl ketals and acetals, preferred ones are those which are based on aliphatic ketones and alde-hydes, such as, for example, acetone, methyl ethyl ketone, methyl propyl ketone, diethyl ketone, methyl isopropyl ketone, methyl isobutyl ketone, methyl tert-butyl ketone, dipropyl ketone, dinonyl ketone, 2-undecanone, and are obtainable from these by reaction with monoalcohols, such as, for example, methanol, ethanol, propanol, iropropanol, butanols, pentanols or higher molecular weight monoalcohols, such as the fatty alcohols, such as, for example, stearyl alcohol.
The following may be mentioned by way of example for aliphatic aldehydes: formaldehyde, acetaldehyde, propionaldehyde, n-butyraldehydc, iso-butyraldehyde, pivalinaldehyde, oenanthaldehyde, 2-ethylhexanal and higher aldehydes. Dialkyl acetals are obtainable from the aldehydes by reaction with the abovementioned monoalcohols.
These dialkyl ketals and acetals are reacted by means of acidic catalysts, such as, for example, p-toluenesulphonic acid, trifluoromethylsulphonic acid, acidically laden ion exchangers, or alkaline catalysts, such as, for example, sodium methylate, sodium ethylate, sodium isopropylate, with known diols, such as ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, triethylene glycol, tripropylene glycol, oligomeric polyethylene or polypropylene glycols up to a molecular weight of 350, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, neopentylglycol, 1,6-hexanediol, 3-methylpentane-1,5-diol, 2,5-hexanediol. Polyetherpolyols of the type known per se and having a functionality of 2, which are initiated on diols or diphenols and whose ether chains consist of ethylene oxide, propylene oxide and/or butylene oxide units, are likewise suitable for this reaction.
The preparation of the bishydroxy-functional compounds of the structure (I) is carried out by transketalization or transacetalation of the dialkyl ketals or acetals of aliphatic ketones or aldehydes with diols while simultaneously distilling off the resulting alcohol. With the use of suitable solvents, the alcohol can also be distilled off as an azeotrope with the solvent. Suitable catalysts for this reaction are acidic an
Jansen Bernhard
Roick Thomas
Thiele Bernd
Bayer Aktiengesellschaft
Gil Joseph C.
Gorr Rachel
Henderson Richard E. L.
LandOfFree
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