Non-ionic polyurethane dispersions having side chains of polyoxyethylene

• US 3,920,598 A
• Filed: 03/18/1974
• Issued: 11/18/1975
• Est. Priority Date: 03/23/1973
• Status: Expired due to Term

• Current Assignee: Harro Witt, Helmut Reiff, Jurgen Lienert, Pramod Gupta, Roland Nast
• Original Assignee: Harro Witt, Helmut Reiff, Jurgen Lienert, Pramod Gupta, Roland Nast
• Inventors: Reiff, Helmut, Nast, Roland, Lienert, Jurgen, Witt, Harro, Gupta, Pramod
• Primary Examiner(s): Tillman, Murray
• Assistant Examiner(s): Koeckert, A.
• Application Number:
  US05/452,180
• Time in Patent Office: 610 Days
• Field of Search: 260/29.2TN
• US Class Current: 524/871
• CPC Class Codes: C08G 18/7818 containing ureum or ureum derivative groups
• CPC Class Codes: C08G 18/7831 containing biuret groups
• CPC Class Codes: C08G 18/8061 masked with compounds having only one group containing active hydrogen

Abstract

A polyurethane which is adapted to be dispersed in water without an emulsifier is prepared by reacting an organic compound having reactive hydrogen atoms determinable by the Zerewitinoff method with an organic diisocyanate having a side chain which contains repeating (O-CH2-CH2) groups. Latices prepared from the polyurethane may be used to prepare films and coatings having improved physical properties.

Claims

1. IN THE PREPARATION OF A POLYURETHANE LATEX BY A ROCESS WHEREIN A DIFUNCTIONAL ORGANIC COMPOUND HAVING REACTIVE HYDROGEN ATOMS AND AN ORGANIC DIISOCYANATE ARE REACTED TOGETHER AND THE RESULTING POLYURETHANE IS DISPERSED IN WATER, THE IMPROVEMENT WHICH COMPRISES REACTING THE SAID COMPOUND HAVING REACTIVE HYDROGENS WITH AN ORGANIC DIISOCYANATE HAVING A MOLECULAR STRUCTURE WHICH CONTAINS AN ALLOPHANATE OR BIURET GROUP ATTACHING A SIDE CHAIN HAVING REPEATING -OCH2-CH2-GROUPS THERETO.

2. The process of claim 1 wherein the said allophanate or biuret diisocyanate is mixed with an organic diisocyanate free from - O-CH2CH2 - groups and the mixture contains at least 5 mol percent of the allophanate or biuret diisocyanate.

3. The process of claim 2 wherein the said mixture contains 10 to 50 mol percent allophanate or biuret diisocyanate.

4. A process for making non-ionic aqueous polyurethane dispersions which are free from emulsifiers which comprises reacting an organic compound having a molecular weight of from about 500 to about 6000 which is difunctional for the purpose of an isocyanato polyaddition reaction and contains terminal hydrogen atoms which are reactive towards isocyanate groups with organic diisocyanates which contain from about 5 to about 100 mol percent of a diisocyanate having polyethlene oxide units and the general formula

5. Polyurethane dispersions prepared from the process of claim 4.

6. The process of claim 4 wherein the reaction product of the organic diisocyanate and the said organic compound having a molecular weight between about 500 and about 6000 is chain extended with an organic compound having reactive hydrogen atoms and a molecular weight below 500.

7. The process of claim 4 wherein the organic diisocyanate is a mixture of one having the said formula and an organic diisocyanate free from side chains containing ethylene oxide.