Patent US4521338A successfully refreshed from Google Patents.
US4521338A
Expired / Lapsed
US
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Process for the preparation of low molecular weight 4,4'-diphenylmethane-uretdione-diisocyanates
Assignee: Bayer AG
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Filing: 1982-08-02
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Granted: 1985-06-04
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Expires: 2002-08-02
Abstract
Abstract Low molecular weight 4,4'-diphenylmethane-uretdione-diisocyanates corresponding to the formula: ##STR1## wherein n is a number from 0 to 1, are made by dimerizing diphenylmethane-4,4'-diisocyanate at a temperature of 50° C. or less in a mixture of non-polar and moderately polar solvents in the presence of a dimerization catalyst. The dimerization product may then be worked up at low temperatures (i.e., ≦50° C.). The dimerization products of diphenylmethane-diisocyanate thus obtained generally have only a small amount of oligomeric uretdione-diisocyanates present. These dimerization products may be used advantageously in the synthesis of polyurethanes.
Inventors
- 👤 Gerhard Grogler
- 👤 Richard Kopp
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 23:11
CPC Classifications
C; C07; C07D; C07D229/00; C08; C08G; C08G18/00; C08G18/06; C08G18/70; C08G18/72; C08G18/77; C08G18/78; C08G18/79; C08G18/798
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
54 words
A process for the production of a low molecular weight 4,4'-diphenylmethane-uretdione-diisocyanate corresponding to the formula: ##STR8## in which n represents a number from 0 to 1, comprising dimerizing a 4,4'-diphenylmethane-diisocyanate at a temperature less than 50° C. in the presence of a catalyst and in an isocyanate-inert solvent-mixture of non-polar and moderately polar solvents.
Claim 2
Dependent Claim
54 words
A process for the production of a low molecular weight 4,4'-diphenylmethane-uretdione-diisocyanate corresponding to the formula: ##STR8## in which n represents a number from 0 to 1, comprising dimerizing a 4,4'-diphenylmethane-diisocyanate at a temperature less than 50° C. in the presence of a catalyst and in an isocyanate-inert solvent-mixture of non-polar and moderately polar solvents.
Claim 3
Dependent Claim
22 words
The process of claim 1 wherein the solubility of the 4,4'-diphenylmethane-diisocyanate in the non-polar solvent is from 5 to 25 wt. %.
Claim 4
Dependent Claim
14 words
The process of claim 1 wherein n represents a number from 0 to 0.5.
Claim 5
Dependent Claim
31 words
The process of claim 1 wherein the non-polar and moderately polar solvents are used in quantities such that the ratio of non-polar to moderately polar solvent is from 1:2 to 2:1.
Claim 6
Dependent Claim
42 words
The process of claim 4 wherein the non-polar solvent is an aliphatic and/or cycloaliphatic hydrocarbon and the moderately polar solvent is selected from the group consisting of aromatic hydrocarbons, chlorinated derivatives of aromatic hydrocarbons, carboxylic acid esters, ketones, ethers and mixtures thereof.
Claim 7
Dependent Claim
15 words
The process of claim 1 wherein the non-polar solvent is an aliphatic and/or cycloaliphatic hydrocarbon.
Claim 8
Dependent Claim
34 words
The process of claim 1 wherein the moderately polar solvent is a compound selected from the group consisting of aromatic hydrocarbons, chlorinated derivatives of aromatic hydrocarbons, carboxylic acid esters, ketones, ethers and mixtures thereof.
Claim 9
Dependent Claim
36 words
The process of claim 1 wherein the solubility of the 4,4'-diphenylmethane-diisocyanate in the non-polar solvent is from 5 to 15 wt. % at room temperature and the dielectric constant of the non-polar solvent is below 2.10.
Claim 10
Dependent Claim
19 words
The process of claim 8 wherein the dielectric constant of the moderately polar solvent is from 2.24 to 10.
Claim 11
Dependent Claim
19 words
The process of claim 1 wherein the dielectric constant of the moderately polar solvent is from 2.24 to 10.
Claim 12
Dependent Claim
20 words
The process of claim 1 wherein the moderately polar solvent is a ketone having a dielectric constant up to 22.
Claim 13
Dependent Claim
23 words
The process of claim 1 wherein the non-polar solvent is selected from the group consisting of petroleum ether, ligroin, petrol and mixtures thereof.
Claim 14
Dependent Claim
12 words
The process of claim 12 wherein the moderately polar solvent is toluene.
Claim 15
Dependent Claim
12 words
The process of claim 1 wherein the moderately polar solvent is toluene.
Claim 16
Dependent Claim
23 words
The process of claim 1 wherein the temperature is maintained below 30° C. during the dimerization reaction and any subsequent purification or separation.
Claim 17
Dependent Claim
12 words
The process of claim 1 wherein the catalyst is a trialkyl phosphine.
Claim 18
Dependent Claim
21 words
The process of claim 16 wherein the catalyst is employed in an amount which is from 0.1 to 1.0 wt. %.
Claim 19
Dependent Claim
45 words
The process of claim 1 wherein from 1 to 2 parts by weight of the non-polar solvent is stirred with one part of 4,4'-diphenylmethane-diisocyanate at room temperature up to the saturation point and then moderately polar solvent is added until a homogeneous solution is produced.
Claim 20
Dependent Claim
12 words
The process of claim 1 wherein the dimerization catalyst is tributyl phosphine.
Claim 21
Dependent Claim
24 words
The process of claim 1 wherein the product 4,4'-diphenylmethane-uretdione-diisocyanate is separated from any unreacted material or by-products at a temperature less than 50° C.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-06-03 | 1988-12-03 | 1989-06-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-06-03 | 1992-12-03 | 1993-06-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-06-03 | 1996-12-03 | 1997-06-04 | $7700.00 | Window Closed / Lapsed |