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
2002-03-06
2003-11-04
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...
C524S590000, C524S591000, C524S839000, C524S840000, C528S044000, C528S045000, C528S060000, C528S061000, C528S085000
Reexamination Certificate
active
06642302
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a hydrophilic/hydrophobic water-soluble or water-dispersible polyurethanes suitable as thickening agents for aqueous systems, having a particularly efficient thickening effect in the high-shear range, as well as its use for the thickening of aqueous systems.
Polyurethane-based thickening agents for aqueous systems are described in numerous publications, (see for example DE-A 1 444 243, DE-A 3 630 319, EP-A-0 031 777, EP-A-0 307 775, EP-A-0 495 373, U.S. Pat. No. 4,079,028, U.S. Pat. No. 4,155,892, U.S. Pat. No. 4,499,233 or U.S. Pat. No. 5,023,309).
A common feature of these thickening agents belonging to the prior art is the simultaneous presence of (i) hydrophilic segments in an amount of at least 50 wt. %, (ii) hydrophobic segments in an amount of at most 10 wt. % and (iii) urethane groups. The term “hydrophilic segments” is understood to mean in particular polyurethane chains with at least 5 chain members whose alkylene oxide units contains at least 60 mole % of ethylene oxide units. The term “hydrophobic segments” is understood to mean in particular hydrocarbons segments with at least 6 carbon atoms that are incorporated within the chain and/or are preferably incorporated in the terminal position.
The thickening agents according to the invention described hereinafter also preferably correspond to this definition.
These polyurethane thickening agents are suitable as auxiliary substances for adjusting the rheological properties of aqueous systems, such as automotive and industrial paints, plaster paints and coating compounds, printing inks and textile dyes, pigment printing pastes, pharmaceutical and cosmetic preparations, plant protection formulations or filler dispersions.
Although the known polyurethane thickeners have a wide application, they are nevertheless insufficiently effective for many areas of application. A particular problem in the use of polyurethane thickeners is that they must exhibit a good effect not only in the range of low shear rates (which is important in particular for the settling behaviour and flow of for example paints), but also at high shear rates (high-shear range) that occur when applying the preparations using for example brushes or rollers, or also by spraying. For these reasons in the prior art two basic types of thickeners for the respective range of the shear rates are as a rule used in a preparation, or further auxiliary substances are added, such as solvents, in order to reduce the low-shear viscosity. This often employed measure leads however to an increase in volatile and/or migration-capable fractions in the paint formulation, which is undesirable in particular for environmental protection reasons.
In the past many attempts have been made in order to improve the effectiveness of aqueous polyurethane thickeners, such as by the incorporation of hydrophobic segments in the polymer chain of the thickener or by the use of hydrophobic side chains. The increasing demands in the market have led however over the last few years to the need for even further improved products. By using thickening agents that are improved compared to the prior art either paints with improved coating properties would be obtained using the same application amount, or alternatively the same coating properties could be achieved by using a lower application amount, which would lead to economic advantages compared to the old systems.
It was an object of the invention to provide new polyurethane-based thickening agents for aqueous or mainly aqueous systems that have an improved effectiveness in the high-shear range.
This object was achieved by the hydrophilic/hydrophobic water-soluble or water-dispersible polyurethanes according to the invention which are described in more detail hereinafter. The essential feature of the invention is the specific incorporation of selected hydrophilic and/or hydrophobic segments by using special alcohols and/or special alcohol mixtures, as well as the use of special polyethers as reaction partners for the isocyanate component.
SUMMARY OF THE INVENTION
The present invention relates to a water-soluble or water-dispersible polyurethane that is a reaction product of
A) at least one polyether polyol a1) having an average functionality of ≧3 and at least one urethane group-containing polyether polyol a2) having an average functionality of ≧4,
B) at least one monoalcohol with 6 to 22 carbon atoms,
C) at least one (cyclo)aliphatic and/or aromatic diisocyanate
D) at least one oxime, monoamine di- and/or polyamine with 2 to 18 carbon atoms,
E) optionally at least one monoisocyanate with 4 to 18 carbon atoms, and
F) optionally at least one polyisocyanate having an average functionality of >2
wherein the starting NCO/OH equivalent ratio is between 0.5:1 to 1.2:1.
The present invention also relates to a process for the production of these water-soluble or water-dispersible polyurethanes by reacting in a one-stage or multi-stage reaction at an NCO/OH equivalent ratio of 0.5:1 to 1.2:1,
A) a mixture of at least one polyether polyol a1) having an average functionality of ≧3 and at least 1 urethane group-containing polyether polyol a2) having an average functionality of ≧4,
B) at least one monoalcohol with 6 to 22 carbon atoms,
C) at least one (cyclo)aliphatic and/or aromatic diisocyanate,
D) at least one oxime, monoamine, diamine and/or polyamine with 2 to 18 carbon atoms,
E) optionally at least one monoisocyanate with 4 to 18 carbon atoms, and
F) optionally at least one polyisocyanate having an average functionality of >2.
The present invention also provides for the use of the polyurethanes according to the invention for thickening aqueous systems.
DETAILED DESCRIPTION OF THE INVENTION
Polyether polyol component A) contains a mixture of a polyether polyol a1) of formula (I):
R
1
[—O—(A)
x
—H]
y
(I),
wherein
R
1
represents an aliphatic or araliphatic hydrocarbon radical with 4 to 36 carbon atoms and optionally having ether oxygen atoms,
A represents ethylene oxide and/or propylene oxide radicals with the proviso that at least 50 mole %, preferably at least 70 mole % and more preferably 100 mole % of the radicals represent ethylene oxide radicals,
x represents a number from 30 to 250, and
y represents a number from 3 to 18, preferably 3 to 6
and a urethane group-containing polyether polyol a2) of formula (II):
wherein
R
1
represents an aliphatic or araliphatic hydrocarbon radical with 4 to 36 carbon atoms optionally containing ether oxygen atoms,
R
2
represents an aliphatic, araliphatic, cycloaliphatic or aromatic radical with 4 to 12 carbon atoms,
A represents ethylene oxide and/or propylene oxide radicals with the proviso that at least 50 mole %, preferably at least 70 mole % and more preferably 100 mole % of the radicals represent ethylene oxide radicals,
x represents a number from 30 to 250, and
y represents a number from 3 to 18, preferably 3 to 6,
z represents a number from 2 to 16, preferably 2, 3 or 4, and t =(y−z).
Monoalcohol component B) contains at least one monohydric alcohol of formula (III):
R
3
—OH (III),
wherein
R
3
represents an aliphatic, cycloaliphatic, aromatic or araliphatic hydrocarbon radical with 6 to 22, preferably 6 to 18, more preferably 8 to 14 carbon atoms and optionally having inert substituents.
The component C) contains at least one diisocyanate of the formula (IV):
OCN—R
4
—NCO (IV),
wherein
R
4
represents an aliphatic, araliphatic, cycloaliphatic or aromatic radical with 4 to 22 carbon atoms and optionally containing inert substituents, e.g. halogen.
It is understood by the skilled artisan that the groups R
3
and R
4
can optionally contain substituents that preferably are inert to the isocyanate group or the hydroxy group of the respective reaction partner.
Component D) contains at least one organic molecule with at least one oxime group and/or at least one primary and/or one secondary amino group and optionally further functional groups.
Component E) contains at least one mono
Manshausen Peter
Mazanek Jan
Sauer Frank
Wamprecht Christian
Bayer Aktiengesellschaft
Gil Joseph C.
Mrozinski, Jr. John E.
Niland Patrick D.
Roy Thomas W.
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