Use of nonionic, water-dispersible polyisocyanates as concrete additives

• US 6,007,619 A
• Filed: 12/11/1997
• Issued: 12/28/1999
• Est. Priority Date: 12/24/1996
• Status: Expired due to Fees

• Current Assignee: Bayer AG
• Original Assignee: Bayer AG
• Inventors: Laas, Hans-Josef, Brahm, Martin, Mazanek, Jan, Reinschmidt, Anke, Knofel, Dietbert, Bottger, Karl-Georg, Schonfelder, Manfred, Kober, Hermann
• Primary Examiner(s): MARCANTONI, PAUL D
• Application Number:
  US08/988,575
• Time in Patent Office: 747 Days
• Field of Search: 106/727, 106/808, 106/823, 524/5, 524/2
• US Class Current: 106/727
• CPC Class Codes: C04B 24/282 Polyurethanes; Polyisocyanates
• CPC Class Codes: C08G 18/282 Alkanols, cycloalkanols or arylalkanols including terpenealcohols
• CPC Class Codes: C08G 18/283 Compounds containing ether groups, e.g. oxyalkylated monohydroxy compounds
• CPC Class Codes: C08G 18/706 the liquid medium being water
• CPC Class Codes: C08G 2115/02 to isocyanurate groups

Abstract

The present invention relates to a process for preparing mortar/concrete compositions by incorporating into the mortar/concrete compositions either before or during the mixing operation a water-dispersible polyisocyanate which

a) has an average isocyanate functionality of 1.8 to 4.0,

b) contains 4.0 to 25.0 wt. % of aliphatically and/or cycloaliphatically bound isocyanate groups (calculated as NCO; molecular weight=42) and

c) contains 5 to 80 wt. % of ethylene oxide units present within polyether chains (calculated as C₂ H₄ O; molecular weight=44), in which

d) the polyether chains contain an average of 5 to 50 ethylene oxide units.

Claims

1. In a process for preparing a mortar/concrete composition by mixing an inorganic binder, an aggregate, water, the improvement which involves incorporating into the mortar/concrete composition either before or during the mixing operation a hydrophilic, strength-enhancing water-dispersible polyisocyanate in solvent-free form which

a) has an average isocyanate functionality of 1.8 to 4.0,

b) contains from 4.0 to 25.0 wt. % of an isocyanate component comprising a group selected from the group consisting of aliphatically-bound isocyanate groups and cycloaliphatically bound isocyanate groups, calculated as NCO;

molecular weight=42, and

c) contains 5 to 80 wt. % of ethylene oxide units present within polyether chains, calculated as C₂ H₄ O;

molecular weight=44, in which

d) the polyether chains contain an average of 5 to 50 ethylene oxide units

wherein the water-dispersible polyisocyanate can be used in an amount up to 10 wt. % based on the weight of the binder.

2. The process of claim 1 wherein the water-dispersible polyisocyanate

a) has an average isocyanate functionality of 1.8 to 3.5,

b) contains 6.0 to 21.5 wt. % of aliphatically bound isocyanate groups, calculated as NCO;

molecular weight=42, and

c) contains 5 to 75 wt. % of ethylene oxide units present within polyether chains, calculated as C₂ H₄ O;

molecular weight=44, in which

d) the polyether chains contain an average of 5 to 25 ethylene oxide units.

3. The process of claim 2 wherein the water-dispersible polyisocyanate is prepared by reacting a polyisocyanate, which is prepared from 1,6-diisocyanatohexane, has an isocyanate group content of 19 to 24 wt. % and a 1,6-diisocyanatohexane monomer content of less than 0.5 wt. % and contains isocyanurate groups, and optionally a group comprising a component selected from the group consisting of uretdione groups and allophanate groups, with a polyethylene glycol monomethyl ether which contains as an average of 5 to 25 ethylene oxide units.

4. The process of claim 2 wherein the water-dispersible polyisocyanate is prepared by reacting 1,6-diisocyanatohexane with a polyethylene glycol monomethyl ether which contains an average of 5 to 25 ethylene oxide units at an NCO/OH equivalent ratio of 6:

1 to 50;

1 in the presence of a compound which accelerates the formation of allophanate groups, and optionally a group comprising a component selected from the group consisting of isocyanurate groups and uretdione groups, and separating unreacted 1,6-diisocyanatohexane monomer until the residual monomer content is less than 0.5 wt. %.

5. The process of claim 1 wherein the water-dispersible polyisocyanate

a) has an average isocyanate functionality of 1.8 to 3.5,

b) contains from 4.0 to 13.0 wt. % of cycloaliphatically bound isocyanate groups, calculated as NCO;

molecular weight=42, and

c) contains 10 to 70 wt. % of ethylene oxide units present within polyether chains, calculated as C₂ H₄ O;

molecular weight=44, in which

d) the polyether chains contain as an average of 5 to 25 ethylene oxide units.

6. The process of claim 5 wherein the water-dispersible polyisocyanate is prepared by reacting 4,4'"'"'-diisocyanatodicyclohexyl-methane with a polyethylene glycol monomethyl ether which contains an average of 5 to 25 ethylene oxide units at an NCO/OH equivalent ratio of from 6:

1 to 50;

1 in the presence of a compound which accelerates the formation of allophanate groups and optionally a group comprising a component selected from the group consisting of isocyanurate groups and uretdione groups, and separating unreacted 4,4'"'"'-diisocyanato-dicyclohexylmethane monomer until the residual monomer content is less than 0.5 wt. %.

7. The process of claim 1 wherein the water-dispersible polyisocyanate is present in an amount of up to 10 wt. %, based on the binder content of the mortar/concrete composition.

8. The process of claim 2 wherein the water-dispersible polyisocyanate is present in an amount of up to 10 wt. %, based on the binder content of the mortar/concrete composition.

9. The process of claim 3 wherein the water-dispersible polyisocyanate is present in an amount of up to 10 wt. %, based on the binder content of the mortar/concrete composition.

10. The process of claim 4 wherein the water-dispersible polyisocyanate is present in an amount of up to 10 wt. %, based on the binder content of the mortar/concrete composition.

11. The process of claim 5 wherein the water-dispersible polyisocyanate is present in an amount of up to 10 wt. %, based on the binder content of the mortar/concrete composition.

12. The process of claim 6 wherein the water-dispersible polyisocyanate is present in an amount of up to 10 wt. %, based on the binder content of the mortar/concrete composition.