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
2000-03-28
2001-06-26
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...
C427S372200, C427S385500, C524S589000, C528S045000
Reexamination Certificate
active
06251988
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to polyurethane solutions having amino-functional heterocyclic stoppers, a process for preparing these polyurethane solutions and the use of the corresponding polyurethane solutions.
2. Description of the Prior Art
Polyurethane solutions are known and are described, e.g., in D. Diederich, Methoden der Organischen Chemie (Houben-Weyl), vol. E20, Georg Thieme Verlag, 1997 and literature cited therein.
Polyurethane solutions are generally high molecular weight reaction products of aliphatic and/or aromatic di- or polyisocyanates with di- or tri-functional polyols and/or diamines. Reaction of the isocyanate compounds with the hydroxyl and/or amino-functional compounds takes place at an equivalent ratio of approximately 1:1 to produce the required high molecular weight.
In order to obtain soluble and readily processable products, the chain building reaction has to be terminated when the desired molecular weight or desired viscosity the polyurethane solutions is achieved. This generally takes place by adding low molecular weight, reactive compounds, such as a monoamine (DE-A-2,633,293), a monoisocyanate or acetanhydride (DE-A-2,500,921, EP-A-0,129,396), a monofunctional alcohol, e.g., methanol, or by adding other chain terminating compounds, e.g., butanonoxime (DE-A-3,142,706).
When practiced on an industrial scale an excess of chain terminator is generally added to ensure reliable stopping of the reaction. This excess, however, may also have a deleterious effect on the properties of the coatings, which may then become manifest in the form of odors, exudation or adhesion problems or by defects in the film due to the formation of bubbles or craters. Also, the storage stability of polyurethane solutions may be impaired. Excess free monoamine, monoisocyanate or reactive monoalcohol may lead to considerable viscosity changes or to serious degradation (associated with an impairment in the properties due to a slow reaction with the urethane or ester bonds in the polymer), especially during storage.
Since polymer solutions generally no longer contain reactive groups, only a physical drying process takes place after application. Chemical linking via reactive groups at the ends of chains with reactive groups in the substrate is not possible.
DE-A-3,401,753 discloses polyurethane solutions with terminal amino groups which are available for subsequent cross-linking reactions. However, these require the subsequent addition of a reaction partner.
An object of the present invention is to provide polyurethane solutions which do not have the disadvantages mentioned above, in particular, to provide polyurethane solutions which contain polyurethanes having a high molecular weight, which can be prepared and stopped reliably and which do not cause any problems due to inadequate adhesion or inadequate optical film properties when used in coatings. Thus, it has to be ensured that any excess amounts of stopper which are added do not impair the storage stability of the solution and do not impair the properties of the coating.
Surprisingly, it has now been found that polyurethane solutions which incorporate amino-functional heterocyclic compounds as stoppers satisfy these requirements. Coatings based on the polyurethane solutions according to the invention have good adhesive properties and a particularly pleasant feel. It was also found that the polyurethane solutions according to the invention are extremely suitable for preparing high quality coatings with high permeability to water vapor and thus exhibit an associated outstanding wearer comfort. The coatings according to the invention, therefore, combine high permeability to water vapor with very good water resistance or waterproof character and a relatively low degree of swelling in water.
SUMMARY OF THE INVENTION
The present invention relates to solutions of polyurethanes in organic solvents, wherein the polyurethanes are the reaction products of
a) one or more at least difunctional polyols having a number average molecular weight of 500 to 16,000,
b) one or more at least difunctional polyisocyanates having a molecular weight of 140 to 1500,
c) optionally one or more low molecular weight at least difunctional alcohols and/or amines having a molecular weight of 32 to 500 and
d) one or more monoamino-functional heterocyclic compounds.
The present invention also relates to a process for preparing these polyurethane solutions by
1) initially preparing an isocyanate-functional polyurethane in a one or two stage reaction by reacting polyol (a), polyisocyanate (b), and optionally low molecular weight component (c),
2) optionally increasing the molecular weight of the product of 1) by chain extension with component (c) and
3) subsequently reacting the product of 2) with a monoamino-functional heterocyclic compound (d) to form a high molecular weight polyurethane which no longer contains any free isocyanate groups, wherein either before, during or after the first reaction step enough organic solvent is added for the resulting polyurethane solution to have a solids content of 9 to 65 wt. %.
Finally, the present invention relates to the use of the polyurethane solutions, wherein at least 50% of monoamino-functional heterocyclic compounds are chemically incorporated via urea bonds, in lacquers, coatings, sealants and/or adhesives.
DETAILED DESCRIPTION OF THE INVENTION
The term polyurethane solution also includes polyurethane/polyurea solutions and also solutions which contain e.g. trimeric, uretdione, allophanate and/or biuret structural units in small amounts in addition to urethane and/or urea structural units. The solutions are generally clear, although they may also include solutions which have a turbid to opaque appearance, but this is less preferable.
In the polyurethane solutions according to the invention the polyurethanes are preferably based on the reaction products of
a) 40 to 92 wt. %, preferably 47 to 88 wt. %, of one or more at least difunctional polyols having a molecular weight of 500 to 16,000,
b) 7 to 50 wt. %, 10 to 40 wt. %, of one or more at least difunctional polyisocyanates having a number average molecular weight of 140 to 1500, preferably 168 to 300,
c) 0 to 20 wt. %, 0.5 to 17 wt. %, of one or more low molecular weight at least difunctional alcohol and/or amines having a number average molecular weight of 32 to 500 and
d) 0.1 to 3 wt. %, 0.3 to 1.10 wt. %, of one or more monoamino-functional heterocyclic compounds.
Polyol components (a) which are suitable for preparing the polyurethane solutions according to the invention include polyester polyols (e.g., as described in Ullmanns Enzyklopadie der technischen Chemie, 4th edition, vol. 19, p. 62-65). Suitable raw materials for preparing these polyester polyols are difunctional alcohols such as ethylene glycol, 1,2- and 1,3-propylene glycol, 1,3-, 1,4- and 2,3-butanediol, 1,6-hexanediol, neopentyl glycol, trimethylhexanediol, triethylene glycol, tetraethylene glycol, hydrogenated bisphenols, trimethylpentanediol, diethylene glycol, dipropylene diglycol, 1,4-cyclohexanediol and 1,4-cyclohexanedimethanol; and difunctional carboxylic acids or their anhydrides such as adipic acid, phthalic acid (anhydride), isophthalic acid, maleic acid (anhydride), terephthalic acid, tetrahydrophthalic acid (anhydride), hexahydrophthalic acid (anhydride), succinic acid (anhydride), fumaric acid, azelaic acid and dimeric fatty acids.
Polyester raw materials, which are suitable for use in smaller amounts, include monocarboxylic acids such as benzoic acid, 2-ethylhexanoic acid, oleic acid, Soya oil fatty acid, stearic acid, peanut oil fatty acid, linoleic acid, nonanoic acid, cyclohexane monocarboxylic acid, isononanoic acid, sorbic acid and konjuenic acid; higher functional carboxylic acids or alcohols such as trimellitic acid (anhydride), butanetetracarboxylic acid, trimeric fatty acids, trimethylolpropane, glycerol, pentaerythritol, castor oil, dipentaerythritol; and other known polyester raw materials.
Other suitable polyol comp
Blum Harald
Schutze Detlef-Ingo
Bayer Aktiengesellschaft
Gil Joseph C.
Niland Patrick D.
Roy Thomas W.
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