Catalyzed pellet heat treatment for thermoplastic polyurethanes
AssigneeBASF SE
InventorsTorben Kaminsky, Dirk Kempfert
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Abstract
The invention relates to a process for preparing a thermoplastic polyisocyanate polyaddition product based on polyisocyanate (i) and compounds which are reactive toward polyisocyanate, with or without the use of chain extenders, a first catalyst (iv) and/or auxiliaries and/or additives (v), wherein a second catalyst is initially vaporized and then applied to the polyisocyanate polyaddition product by condensation, and to the products prepared therefrom.
Claims15
A process for preparing a thermoplastic polyisocyanate polyaddition product based on polyisocyanate (i) and compounds (ii) which are reactive toward polyisocyanate, with or without the use of chain extender (iii), a first catalyst (iv) and/or auxiliaries and/or additives (v), which react with one another in a first step, wherein, in a second step, a second catalyst (vi) which accelerates the reaction between the polyisocyanate (i) and the compounds (ii) which are reactive toward polyisocyanate is applied to the polyisocyanate polyaddition product prepared in this way, where the second catalyst (vi) is initially converted into a mist and/or vaporized and is then applied to the polyisocyanate polyaddition product.
The process according to any of the preceding claims, wherein the catalyst (vi) is vaporized and/or atomized to form a catalyst mist in a first space and is subsequently applied to the polyisocyanate polyaddition product in a second space.
The process according to any of the preceding claims, wherein the catalyst (vi) is vaporized and/or atomized in a closed system and is thereby applied to the polyisocyanate polyaddition product.
The process according to any of the preceding claims, wherein the catalyst (vi) is heated to not more than 10° C. below its decomposition temperature during vaporization, preferably to not more than 20° C. below, more preferably to not more than 30° C. below and particularly preferably to not more than 50° C. below, its decomposition temperature.
The process according to any of the preceding claims, wherein the temperature during vaporization of the catalyst is in the range from 30° C. to 160° C., preferably from 50° C. to 150° C. and more preferably from 80° C. to 140° C.
The process according to any of the preceding claims, wherein the temperature of the second catalyst (vi) during application is less than 50° C. above the Vicat temperature of the polyisocyanate polyaddition product, preferably less than 20° C. above, more preferably less than 10° C. above, more preferably below, the Vicat temperature, even more preferably at least 5° C. and particularly preferably at least 10° C. below the Vicat temperature.
The process according to at least one of the preceding claims, wherein the polyisocyanate polyaddition product is heat-treated at a temperature in the range from 10 to 150° C., preferably 50-120° C., after application of the second catalyst.
Dependencies are inferred from the claim text.