Claims
- 1. A process for the production of microporous coatings comprising:
- (a) mixing an NCO-prepolymer prepared from polyisocyanates with compounds containing at least two isocyanate-reactive hydrogen atoms with about 3 to 40% by weight, based on the NCO-prepolymer, of a substantially inert, with respect to isocyanate groups, viscosity-reducing, non-migrating liquid organic compound miscible with said NCO-prepolymer as a plasticizer, wherein
- (i) said NCO-prepolymer is used free from solvents, has a viscosity of more than about 500 cP at 25.degree. C. and a molecular weight of from about 300 to 20,000,
- (ii) said plasticizer has a volatility of less than 10% weight loss after storage for 72 hours at 90.degree. C., and
- (iii) the resultant NCO-prepolymer-plasticizer mixture has a viscosity of less than about 15,000 cP at 20.degree. C.,
- (b) dispersing 3 to 300% by weight of water, based on the NCO-prepolymer, into the NCO-prepolymer-plasticizer mixture to form a water-in-oil emulsion,
- (c) adding a polyamine to the water-in-oil emulsion in a quantity substantially equivalent to the isocyanate groups.
- (d) applying a coating of the water-in-oil emulsion to a substrate and
- (e) hardening the coating by evaporating the chemically unbound water from said coating.
- 2. A process for the production of microporous coatings comprising:
- (a) mixing an NCO-prepolymer prepared from polyisocyanates with compounds containing at least two isocyanate-reactive hydrogen atoms with about 3 to 40% by weight, based on the NCO-prepolymer, of a substantially inert, with respect to isocyanate groups, viscosity-reducing, non-migrating liquid organic compound miscible with said NCO-prepolymer as a plasticizer, wherein
- (i) said NCO-prepolymer is used free from solvents, has a viscosity of more than about 500 cP at 25.degree. C. and a molecular weight of from about 300 to 20,000,
- (ii) said plasticizer has a volatility of less than 10% weight loss after storage for 72 hours at 90.degree. C., and
- (iii) the resultant NCO-prepolymer-plasticizer mixture has a viscosity of less than about 15,000 cP at 20.degree. C.,
- (b) dispersing 3 to 300% by weight of water, based on the NCO-prepolymer into the NCO-prepolymer-plasticizer mixture to form a water-in-oil emulsion,
- (c) adding a polyamine to the water-in-oil emulsion in a quantity substantially equivalent to the isocyanate groups,
- (d) directly coating the water-in-oil emulsion on a substrate, and
- (e) hardening the coating by evaporating the chemically unbound water from said coating.
- 3. The process of claim 2 wherein the polyamine is dissolved in water.
- 4. The process of claim 3 wherein a catalyst capable of catalyzing the reaction of isocyanate groups with water is added to the water-in-oil emulsion.
- 5. A process for the production of microporous isocyanate polyaddition product coatings comprising:
- (a) mixing an NCO-prepolymer prepared from polyisocyanates with compounds containing at least two isocyanate-reactive hydrogen atoms with about 3 to 40% by weight, based on the NCO-prepolymer, of a plasticizer wherein
- (i) the NCO-prepolymer contains less than about 1 wt. % of volatile substances which can be removed over a period of 1 hour in a vacuum of 12 Torr, has a viscosity of more than about 500 cP at 25.degree. C. and has a molecular weight of from about 300 to 20,000,
- (ii) the plasticizer is an organic compound which has a volatility of less than 5% weight loss after storage for 72 hours at 90.degree. C., is chemically inert to isocyanate groups, is miscible with the NCO-prepolymer, and has an affinity for the ultimately formed isocyanate polyaddition product, and
- (iii) the mixture has a viscosity of less than about 15,000 cP at 20.degree. C.,
- (b) adding about 3 to 300 wt. % of water based on the NCO-prepolymer to said mixture to form a water in oil emulsion, said water having dispersed therein a diamine in a quantity substantially equivalent to the isocyanate groups to form an isocyanate polyaddition product with the NCO-prepolymer,
- (c) applying a coating of the water-in-oil coating emulsion to a substrate, and
- (d) hardening the coating by evaporating the chemically unbound water from it at temperatures below the boiling point of the lowest boiling point volatile contained in the coating.
Priority Claims (1)
Number |
Date |
Country |
Kind |
2448133 |
Oct 1974 |
DEX |
|
Parent Case Info
This is a continuation of application Ser. No. 616,736, filed Sept. 25, 1975, now abandoned.
US Referenced Citations (12)
Foreign Referenced Citations (2)
Number |
Date |
Country |
6800529 |
Jul 1968 |
NLX |
1193231 |
May 1970 |
GBX |
Non-Patent Literature Citations (1)
Entry |
Weast et al., Handbook of Chemistry and Physics, 46th ed., The Chemical Rubber Co., Cleveland, 1965, p. c-586. |
Continuations (1)
|
Number |
Date |
Country |
Parent |
616736 |
Sep 1975 |
|