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
2002-03-20
2003-10-14
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...
C526S301000, C526S302000, C525S063000, C525S902000, C523S201000, C523S501000
Reexamination Certificate
active
06632915
ABSTRACT:
The present invention relates to novel polyurethanes and to novel polyurethane-based graft copolymers. The present invention also relates to novel processes for preparing polyurethanes and polyurethane-based graft copolymers. The present invention further relates to the use of the novel polyurethanes and of the novel polyurethane-based graft copolymers to prepare coating materials, adhesives, and sealing compounds. Furthermore, the present invention relates to novel coating materials, adhesives, and sealing compounds, especially aqueous coating materials, adhesives, and sealing compounds. The present invention relates not least to novel coatings, adhesive films, and seals obtainable from the novel, especially aqueous, coating materials, adhesives, and sealing compounds. In particular the present invention relates to single-coat or multicoat decorative and/or protective paint systems, especially multicoat color and/or effect paint systems.
Graft copolymers soluble or dispersible in water are known from European patent EP-A-0 608 021. They consist of a hydrophobic olefinically unsaturated polyurethane core and a hydrophilic acrylic copolymer shell with an acid number of from 30 to 120 mg KOH/g. The hydrophobic olefinically unsaturated polyurethane is prepared by reacting low molecular mass diols or polyester diols with an acid number of less than 5 mg KOH/g with diisocyanates and 1-(1-isocyanato-1-methylethyl)-3-(1-methylethenyl)benzene (dimethyl-m-isopropenylbenzyl isocyanate), which results in ethylenearylene groups, especially terminal ethylenearylene groups. Subsequently, a mixture of olefinically unsaturated monomers is polymerized in solution in the presence of the hydrophobic olefinically unsaturated polyurethane, after which the resulting graft copolymer is neutralized and dispersed in water to give a secondary dispersion. These known secondary dispersions are used for preparing clearcoat materials. Pigmented coating materials or sealing compounds and adhesives are not disclosed in EP-A-0 608 021. The specific core/shell structure comprising a hydrophobic polyurethane core and a hydrophilic polyacrylate shell means some cases prove disadvantageous here.
German patent DE-C-197 22 862 discloses a graft copolymer obtainable by polymerizing olefinically unsaturated monomers in a dispersion of an olefinically unsaturated polyurethane containing hydrophilic functional groups and having on average from 0.05 to 1.1 polymerizable double bonds per molecule. According to DE-C-197 22 862, the polyurethane main chains can be prepared using not only diisocyanates but also polyisocyanates, whose functionality is lowered by adding monoisocyanates. 1-(1-Isocyanato-1-methylethyl)-3-(1-methylethenyl)benzene is given by way of example as a monoisocyanate. Where it is used, it contributes to a certain extent to the polymerizable double bond content of the polyurethane, although the compounds envisaged for its introduction primarily comprise compounds containing isocyanate-reactive functional groups and olefinically unsaturated double bonds, such as hydroxyalkyl (meth)acrylates, for example. Owing to the mode of preparation of the polyurethane, the use of 1-(1-isocyanato-1-methylethyl)-3-(1-methylethenyl)-benzene results primarily in terminal ethylenearylene groups.
The same polyurethane and, respectively, the graft copolymer based on it are also disclosed in German patent application DE-A-196 45 761. Here again, use is made of 1-(1-isocyanato-1-methylethyl)-3-(1-methylethenyl)benzene, referred to therein as isopropenyl-alpha,alpha-dimethylbenzyl isocyanate.
The known graft copolymers of DE-C-197 22 862 and DE-A-196 45 761 are in the form of primary dispersions and are very highly suitable for preparing aqueous coating materials, especially aqueous basecoat materials. The aqueous basecoat materials may be used with advantage for the wet-on-wet technique, in which the aqueous basecoat material is applied to a primed or unprimed substrate and then the resulting aqueous basecoat film is dried without being crosslinked. Atop the dried aqueous basecoat film there is then applied a clearcoat material, after which the aqueous basecoat film and the clearcoat film are cured jointly to form a multicoat color and/or effect paint system.
In this procedure, however, when using powder slurry clearcoat materials, cracking may occur in the clearcoat on baking and/or there may be delamination of the clearcoat, particularly after condensation exposure. Furthermore, popping marks may appear.
Not least it is possible in some cases for the olefinically unsaturated group content of the polyurethanes to prove too low for complete grafting, so that a large part of the monomers to be grafted on form separate homopolymers and/or copolymers alongside the polyurethane, and can adversely affect the performance properties of the graft copolymers and of the coating materials, adhesives, and sealing compounds prepared using them.
Because of its high reactivity, the ethenylarylene group is a very good grafting site for the attachment of olefinically unsaturated monomers by polymerization. However, the introduction of these groups by way of 1-(1-isocyanato-1-methylethyl)-3-(1-methylethenyl)benzene causes problems, since owing to the steric hindrance the isocyanate group is comparatively tardy in reacting, necessitating either long reaction times and/or high reaction temperatures, both of which may lead to product damage. Moreover, this compound cannot be used easily to introduce pendant ethenylarylene groups into the polyurethanes.
It is an object of the present invention to provide novel hydrophilic and hydrophobic olefinically unsaturated polyurethanes which contain not only terminal but also pendant ethenylarylene groups, which can be prepared purposively and simply without the risk of product damage, and which constitute outstanding graft bases for olefinically unsaturated monomers.
It is a further object of the present invention to find a novel process for preparing olefinically unsaturated polyurethanes which have purposively and simply without the risk of product damage, yields hydrophilic or hydrophobic polyurethanes containing pendant and/or terminal ethenylarylene groups.
Yet another object of the present invention is to find novel graft copolymers, particularly in the form of primary dispersions, which can be prepared simply, purposively, and without risk of product damage and which in particular have a core/shell structure with a hydrophobic core formed from copolymerized monomers and with a hydrophilic shell formed from a hydrophilic polyurethane.
Still another object of the present invention is to provide novel aqueous and nonaqueous coating materials, adhesives, and sealing compounds based on polyurethane and having very good performance properties. The intention in particular is to provide novel coating materials, especially novel aqueous coating materials, specifically novel aqueous basecoat materials, which no longer have the disadvantages of the prior art but are instead outstandingly suitable for application by the wet-on-wet technique. In this context, even when using powder clearcoat slurries, there ought to be no cracking (mud cracking) in the clearcoats, delamination of the clearcoats following condensation exposure, or popping marks or pinholes. The novel coating materials ought to have a very good storage stability, outstanding application properties, such as very good leveling and very little tendency to run even at high film thicknesses, an outstanding overall appearance, and a high chemical and weathering stability.
Found accordingly has been the novel polyurethane containing at least one pendant and/or at least one terminal ethenylarylene group and preparable by
(1) reacting at least one polyurethane prepolymer (B1) containing at least one free isocyanate group with
(2) at least one adduct (B2) obtainable by reacting
(2.1) at least one ethenylarylene monoisocyanate with
(2.2) at least one polyol, polyamine and/or at least one compound containing at least one hydroxyl group and at least one amino
Angermüller Harald
Schwarte Stephan
Wegner Egon
BASF Coatings AG
Gorr Rachel
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