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
2002-11-26
2004-11-30
Gorr, Rachel (Department: 1711)
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...
C524S837000, C524S832000, C524S846000
Reexamination Certificate
active
06825268
ABSTRACT:
The present invention relates to polyurethane or polyurethane polymer hybrid dispersions with reduced hydrophilicity, methods for producing the same and the use thereof.
The binder class consisting of aqueous or water-based polyurethanes has been known for more than 40 years. The property profile of the water-based polyurethanes has continuously been improved in the past decades, which is impressively demonstrated by a large number of patents and publications on this subject area. Regarding the chemistry and technology of water-based polyurethanes, reference may be made to D. Dieterich, K. Uhlig in
Ullmann's Encyclopedia of Industrial Chemistry, Sixth Edition
1999
Electronic Release
. Wiley-VCH; D. Dieterich in
Houben
-
Weyl, Methoden der Organischen Chemie.
Vol. E20, H. Bartl, J. Falbe (editors), Georg Thieme Verlag, Stuttgart 1987, page 1641 et seq.; D. Dieterich, Prog. Org. Coat. 9 (1981) 281-330; J. W. Rosthauser, K. Nachtkamp, Journal of Coated Fabrics 16 (1986) 39-79; R. Arnoldus, Surf. Coat. 3 (Waterborne Coat.) (1990), 179-98.
The fact that aqueous polyurethanes have become increasingly important commercially precisely in recent years is due to three reasons:
1. The increasingly stringent environmental legislation requires the development of ecologically and physiologically tolerated products for which the emissions of solvents and other volatile organic compounds (VOC) have been reduced to a minimum.
2. The use of expensive organic solvents in conventional and aqueous polyurethanes is undesirable for economic reasons.
3. The performance of water-based polyurethanes reaches or surpasses that of the conventional isocyanate- and/or solvent-containing polyurethanes.
Water-based polyurethanes are becoming more and more important as binders also in applications involving construction chemistry. In particular, low-solvent (low VOC) or solvent-free (zero VOC) polyurethane dispersions and polyurethane polymer hybrid dispersions which have a high solids content and can be made available with the aid of efficient and universal preparation processes are desired in construction chemistry.
However, it is precisely in applications involving construction chemistry that binders which have high elasticity and, in the formulated state, do not tend to embrittlement, have a high early water resistance and can withstand continuous loading with water without significant swelling are required. Optimum material properties (combination of high tensile strength and high elongation at the tensile strength) can be achieved only as water-based polyurethanes based on polypropylene glycols. Polypropylene glycols also have the necessary saponification stability. However, conventional polyurethane (polymer hybrid) dispersions based on polypropylene glycols have a hydrophilicity which is not negligible in practice.
Polyurethane dispersions and polyurethane polymer hybrid dispersions based on polypropylene glycols are already sufficiently well known from the patent document WO 99/50 325, U.S. Pat. No. 5,576,382, EP-A 712 877, DE 199 49 971, WO 99/16805 and U.S. Pat. No. 5,859,111.
Water-based polyurethanes in which the imparting of water repellency to the polyurethane backbone internally in the polymer led to material properties better than or comparable with the base system have, however, been unknown to date.
It was therefore the object of the present invention to develop a polyurethane (polymer hybrid) dispersion which has reduced hydrophilicity and does not have the stated disadvantages of the prior art but possesses good performance characteristics and at the same time can be produced taking into account ecological, economic and physiological aspects.
This object was achieved, according to the invention, by providing a polyurethane or polyurethane polymer hybrid dispersion which is obtainable by reacting
a) 50 to 100 parts by weight of a hydrophobically modified block copolymer (A)(i) having two or more hydroxyl groups and a molecular weight of 500 to 6 000 dalton, comprising 10 to 90% by weight of a polymer having properties imparting water repellency and 90 to 10% by weight of a polypropylene oxide polymer, and/or
50 to 100 parts by weight of a hydrophobic block copolymer (A)(ii) having two or more hydroxyl groups and a molecular weight of 500 to 6 000 dalton, comprising two or more hydrophobic alkylene oxides, and/or
50 to 100 parts by weight of a hydrophobically modified random copolymer (A)(iii) having two or more hydroxyl groups and a molecular weight of 500 to 6 000 dalton, comprising 10 to 90% by weight of a hydrophobic alkylene oxide in combination with suitable initiator molecules and 90 to 10% by weight of propylene oxide,
b) 14 to 140 parts by weight of a polyol component (B), containing
b
1
) 2 to 20 parts by weight of a low molecular weight and anionogenic polyol component (B)(i) having two or more hydroxyl groups and one or more carboxyl and/or sulfo group(s) inert to polyisocyanates and a molecular weight of 100 to 1 000 dalton,
b
2
) if required, 2 to 20 parts by weight of low molecular weight polyol component (B)(ii) having two or more hydroxyl groups and a molecular weight of 50 to 499 dalton,
b
3
) if required, 10 to 100 parts by weight of a further polymeric polyol (B)(iii) having two or more hydroxyl groups and a molecular weight of 500 to 6 000 dalton,
c) 25 to 250 parts by weight of a polyisocyanate component (C) comprising at least one polyisocyanate, polyisocyanate derivative or polyisocyanate homolog having two or more aliphatic or aromatic isocyanate groups,
d) 2 to 20 parts by weight of a neutralizing component (D),
e) 3 to 30 parts by weight of a chain-extender component (E) and
f) 100 to 5 000 parts by weight of water
to give a solvent-free or low-solvent polyurethane dispersion and, if required, then allowing said dispersion to react further with
g) 117.5 to 3 200 parts by weight of a monomer component (F) comprising at least one monomer having one or more double bonds capable of free radical polymerization and
h) 0.5 to 50 parts by weight of an initiator component (G) comprising at least one lipophilic free radical initiator having one or more thermally labile azo or peroxo groups
to give a solvent-free or low-solvent polyurethane polymer hybrid dispersion.
It has in fact surprisingly been found that, by using hydrophobically modified block copolymers and/or hydrophobic block copolymers and/or hydrophobically modified random copolymers as polyols, not only are polyurethane (polymer hybrid) dispersions having a reduced hydrophilicity or water absorption obtainable but these can moreover be produced in solvent-free or low-solvent form and with high solids contents. In addition, it was not foreseeable that the polyurethane (polymer hybrid) dispersions according to the invention could have only a very low requirement for stabilizing groups and have excellent mechanical properties in comparison with polyurethane (polymer hybrid) dispersions based on pure polypropylene glycols. Owing to stronger orientation or phase separation of hard segments and soft segments (hydrophobically modified block copolymers and/or hydrophobic block copolymers and/or hydrophobically modified random copolymers) in the polyurethane polymer according to the invention, the carboxylate and/or sulfonate groups required for stabilization are sterically shielded to a lesser extent and can therefore better stabilize the micelles of the polyurethane (polymer hybrid) dispersion. In the case of polyurethane (polymer hybrid) dispersions having soft segments based on pure polypropylene glycols, this effect does not exist and some of the carboxylate and/or sulfonate groups required for stabilization are therefore present in “deactivated” form.
The polyurethane (polymer hybrid) dispersion according to the invention, having reduced hydrophilicity, is defined by its multistage method of production. In reaction stage a), a solvent-free or low-solvent polyurethane dispersion is first produced and, if required, is then reacted further, in reaction stage b), to give a solvent-free or low-solvent polyuret
Kern Alfred
Maier Alois
Reichel Frank
Reusmann Gerhard
Steidl Norbert
Fulbright & Jaworski L.L.P.
Gorr Rachel
SKW Bauwerkstoffe Deutschland GmbH
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