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
1999-12-01
2003-08-05
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...
C524S505000, C524S425000, C524S423000, C524S356000, C524S354000, C524S355000, C524S451000, C524S492000, C524S474000
Reexamination Certificate
active
06602973
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method for producing one-component sealing- and coating compounds with a polyurethane base.
2. Description of the Related Art
Well known and precisely examined are binding agents for sealing- and coating compounds which contain isocyanate-prepolymers which can be produced by reaction of isocyanates with molecules with active hydrogen atoms like amines and alcohols and cure under the influence of humidity. DE-A 1 520 139 for example describes a procedure to produce moisture curing mixtures of polyisocyanates and polyketimines or polyaldimines, using isocyanate-prepolymers as polyisocyanate component. DE-A 2 018 233 describes moisture-curable preparations from isocyanate groups containing binding agents and polyoxazolidines.
EP-A 0 702 039 describes a procedure to produce isocyanate-prepolymers by reaction of aromatic or cycloaliphatic diisocyanates with a polyol component providing that there is a rest-content of monomeric diisocyanates of less than 0.5 weight % contained in the isocyanateprepolymers. When cycloaliphatic diisocyanates are used, the excessive diisocyanate has to be removed after the reaction has been finished by thin-layer destillation until the desirable rest content of less than 0.5 weight % is reached. Furthermore it is known from EP-A 0 702 039 and from DE-A 1 520 139 to add filling material and H
2
O-reactive hardener to the mentioned isocyanate-prepolymer with low rest content of monomeric diisocyanates in order to produce sealing- and coating material. To guarantee constancy of quality and storage stability of sealing- and coating material on the basis of already described prepolymers only a low content of water is allowed to exist. This way for example, a reaction of moisture which is introduced by the filling material with free isocyanate groups under cleavage of CO
2
can lead to a dangerous increase of pressure within the bucket. Apart from that, we see that—in the presence of hydrolysis-sensitive, latent amine curing agents for example of the type of oxazolidines, ketimines or aldimines—the lowest degree of rest moisture by reaction with the curing agent leads to a thickening or curing of the material in the bucket. After a certain degree of viscosity of more than 8000 mPas is reached, the material is no more brushable or otherwise applicable. That is why in practise expensive drying techniques like for example dehydrating agents or a very costly physical predrying are applied.
SUMMARY OF INVENTION
Based on this, the invention had for its purpose to provide a manufacturing process of sealing- and coating compounds so that an improved storage stability plus a simultaneous reduction of processing costs can be attained.
The following steps show how the problem is solved according to the invention by some in-situ process:
stirring a mixture containing a polyol component and a diisocyanate component so that an isocyanate-prepolymer with a rest of monomeric diisocyanate of >2 weight % is obtained intermediary.
dispersing of pigments and anorganic filling material and adding of solvent while stirring, so that the rest of the monomer diisocyanate reacts with the moisture that is introduced by the filling material and a H
2
O-content of <0.01 weight % is obtained in the reaction mixture.
adding a H
2
O-reactive latent curing agent and at least one catalyst, if necessary, and air-proof filling of the resulting sealing- and coating compound.
REFERENCES:
patent: 4456718 (1984-06-01), Brinkmann et al.
patent: 5266145 (1993-11-01), Duck et al.
patent: 5290905 (1994-03-01), Komiya et al.
patent: 269 155 (1987-10-01), None
patent: 41 02 341 (1992-07-01), None
patent: 44 29 076 (1996-02-01), None
patent: 0 510 476 (1992-04-01), None
patent: 516110 (1992-12-01), None
Hiller Michael
Moroni Wilko
Schäfer Martin
Gorr Rachel
Pendorf & Cutliff
Sika Chemie GmbH
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