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Control of Viscosity in Isocyanate Containing Mixtures

IP.com Disclosure Number: IPCOM000078503D
Original Publication Date: 1973-Jan-01
Included in the Prior Art Database: 2005-Feb-26
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

deCormier, FS: AUTHOR [+3]

Abstract

Coating mixtures containing particles in a polymeric system, including an isocyanate containing material, often exhibit unpredictable viscosity changes. Such viscosity changes are especially noted to occur after isocyanate addition. The changes in viscosity are believed to be due to reactions occurring between reactive sites on the particles and the isocyanate. As a result of such reactions, viscosity is usually observed to increase rapidly. Uncontrolled high viscosity normally results in poor quality coatings.

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Control of Viscosity in Isocyanate Containing Mixtures

Coating mixtures containing particles in a polymeric system, including an isocyanate containing material, often exhibit unpredictable viscosity changes. Such viscosity changes are especially noted to occur after isocyanate addition. The changes in viscosity are believed to be due to reactions occurring between reactive sites on the particles and the isocyanate. As a result of such reactions, viscosity is usually observed to increase rapidly. Uncontrolled high viscosity normally results in poor quality coatings.

Undesirable viscosity changes are avoided or diminished by reacting or removing the reaction sites from the particles, before the particles come into contact with the isocyanate in the coating mixture. This is accomplished by, for example, treating the particles with an isocyanate containing composition prior to the addition of the particles to the mixture. Pretreatment of the particles with an isocyanate composition results in reactions at the reaction sites of the particles, so that such sites are then not available to affect the viscosity of the coating mixture. The prereacted particles are added to the coating mixture, either with the isocyanate reaction pretreatment product, or with the isocyanate pretreatment reaction product removed with solvent, so that only a relatively nonreactive particle is added. In either case, coating mixtures with prereacted particles do not exhibit the large unexpected...