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
2001-09-21
2004-07-13
Sergent, Rabon (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...
C428S294700, C428S295100, C428S297400, C428S423100, C428S423400, C428S425100, C524S590000, C524S591000, C524S839000, C524S840000, C524S864000, C524S871000, C524S874000, C524S875000, C528S059000, C528S060000, C528S061000, C528S065000, C528S071000, C528S076000, C528S080000, C528S085000
Reexamination Certificate
active
06762241
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to polyurethane solutions with alkoxysilane structural units, processes for the preparation of polyurethane solutions containing alkoxysilane structural units and the use of polyurethane solutions containing alkoxysilane structural units.
Polyurethane solutions have been known for a long time, e.g. D. Diederich, Methoden der Organischen Chemie [Methods of Organic Chemistry] (Houben-Weyl), volume, E 20, Georg Thieme Verlag, 1997 and the literature cited there.
As a rule, polyurethane solutions are high molecular weight reaction products of aliphatic and/or aromatic di- or polyisocyanates with di- or trifunctional polyols and/or diamines. The reaction of the isocyanate-functional compounds with the hydroxyl- and/or amino-functional compounds takes place here close to the equivalence point to achieve the desired high molecular weights.
To obtain products which are soluble and readily processable, the chain build-up reaction must be stopped when the desired molecular weights or viscosities of the polyurethane solutions are reached. This is usually effected by addition of low molecular weight reactive compounds, such as e.g. monoamine (DE-A 2 633 293), monoisocyanate or acetic anhydride (DE-A 2 500 921, EP-A 129 396), by addition of reactive monofunctional alcohols, such as methanol, or by addition of other compounds having a chain-stopping action, such as e.g. butanone oxime (DE-A 3 142 706).
In technical practice, as a rule a certain excess of stopper reagent is added here in order to ensure reliable stopping. However, this excess can have an adverse effect on coating properties, which can manifest itself e.g. by an odour nuisance, by exudation, by adhesion problems and by the formation of defects in the film due to bubbles and cratering. The storage stability of such solutions can also be impaired as a result. Excess free monoamine, monoisocyanate or even excess reactive monoalcohol can lead to considerable changes in viscosity up to serious degradation phenomena, associated with a loss in properties, due to a creeping reaction with urethane or ester bonds in the polymer, especially during the storage times which are unavoidable in practice.
Since polyurethane solutions as a rule no longer contain reactive end groups, only physical drying takes place after application. Chemical crosslinking via reactive groups at the chain end to form very high molecular weight polymers with an improved level of properties is thus no longer possible.
DE-A 3 401 753 discloses polyurethane solutions with terminal aromatic amino groups which are available for a later crosslinking reaction. However, this requires subsequent addition of a reaction partner.
JP 0 8253 545 describes crosslinkable urethane resin compositions which comprise compounds with two isocyanate-reactive groups and a hydrolysable silyl group. The urethane resins comprise exclusively laterally bonded silyl groups. This leads to crosslinked adhesives or coatings with a high hardness, but only a low elasticity or extensibility. Compounds with two isocyanate-reactive groups and a hydrolysable groups are furthermore unsuitable as a stopper reagent.
The object of the invention was therefore to provide polyurethane solutions which do not have the disadvantages mentioned. In particular, polyurethane solutions which comprise polyurethanes with high molecular weights, can be prepared and stopped reliably, and furthermore when used in coatings cause no problems due to odour nuisance, exudation, inadequate adhesion or inadequate optical properties of the film are to be provided. It must be ensured here that any excess amounts of stopper agent added do not have an adverse effect on the storage stability of the solution and on the properties of the coating, and also that no harmful effect on the health of processors and workers is to be expected.
Surprisingly, it has now been found that polyurethane solutions which comprise in incorporated form compounds with an isocyanate-reactive group and at least one alkoxysilane group as a stopper agent meet the stated requirements. Moreover, an improved stability to hydrolysis, a very good adhesion and a particularly pleasant handle of coatings based on the polyurethane solutions according to the invention have also surprisingly been found. Surprisingly, it has also been found that the polyurethane solutions according to the invention are very particularly suitable for the production of high-quality coatings with a high permeability to water vapour and, associated with this, an excellent wearing comfort. The coatings according to the invention combine here a high permeability to water vapour with a very good water resistance or wet-fastness and a relatively low swelling in water.
Polyurethane solutions which comprise in incorporated form a compound with an isocyanate-reactive group and an alkoxysilane group as a stopper agent and additionally a compound with at least two isocyanate-reactive groups and at least one alkoxysilane structural unit in small amounts surprisingly likewise lead to coatings which meet the abovementioned requirements and moreover have both excellent mechanical properties of the films, in particular a high extensibility and elasticity, and at the same time very high melting or softening temperatures, which is very advantageous for many applications, e.g. in coating of textiles.
Polyurethane solutions which comprise as the stopper agent a reaction product, containing aspartic acid ester structural units, of a compound with a primary amino group and at least one alkoxysilane group with a maleic acid dialkyl ester surprisingly also meet the abovementioned requirements, in spite of the known reduced reactivity of the aspartic acid ester structural units. They moreover have the further advantage that larger amounts of stopper agent are also employed, also at a very early point in time of the reaction and also without the presence of organic solvents, without the risk of the formation of sparingly soluble or insoluble ureas of gel particles. Furthermore, on the other hand coatings which have, in addition to excellent mechanical properties of the film, an excellent, particularly soft handle and a very high wearing comfort, which is very important for many uses, surprisingly can be obtained.
SUMMARY OF THE INVENTION
The invention therefore provides polyurethane solutions with alkoxysilane structural units, characterized in that they are reactions products, in organic solution, of
a) at least one at least difunctional polyol of molecular weight 500 to 16,000,
b) at least one at least difunctional polyisocyanate of molecular weight 140 to 1,500,
c) at least one low molecular weight at least difunctional alcohol and/or amine of molecular weight 32 to 500,
d) at least one compound containing at least one alkoxysilane group and an isocyanate-reactive group and
e) optionally a monofunctional substance with an amino, alcohol or oxime group,
the amount of stopper agent equivalents from component d) being at least 50% of the total amount of stopper agent from d) and e).
The invention preferably provides polyurethane solutions with alkoxysilane structural units, characterized in that they are reaction products, in organic solution, of
a) 40 to 92 wt. % of at least one at least difunctional polyol of molecular weight 500 to 16,000,
b) 7 to 50 wt. % of at least one at least difunctional polyisocyanate of molecular weight 140 to 1,500,
c) 0.5 to 20 wt. % of at least one low molecular weight at least difunctional alcohol and/or amine of molecular weight 32 to 500,
d) 0.1 to 5 wt. % of at least one compound containing at least one alkoxysilane group and an isocyanate-reactive group and
e) optionally a monofunctional substance with an amino, alcohol or oxime group,
the amount of stopper agent equivalents from component d) being at least 75% of the total amount of stopper agent from d) and e).
The invention particularly preferably provides polyurethane solutions, characterized in that they are reaction products, in organic solution, of
a) 47 to 88
Blum Harald
Schütze Detlef-Ingo
Bayer Aktiengesellschaft
Gil Joseph C.
Matz Gary F.
Roy Thomas W.
Sergent Rabon
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