Process for preparing urea-dione polyisocyanate with improved monomer stability

A polyisocyanate and diisocyanate technology, applied in the field of polyurethane plastics, can solve problems such as insufficient stability

Inactive Publication Date: 2002-02-06
BAYER AG
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] However, the main disadvantage of uretdione polyisocyanates prepared with tertiary phosph

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0066] In 1000g (5.95mol) of hexamethylene diisocyanate (HDI), at room temperature and under the protection of dry nitrogen, sequentially add 2g (0.2%) N, N-diethylurea as a stabilizer, 10g (1.0%) 1 , 3-butanediol as a cocatalyst and 3 g (0.3% / 0.015 mol) of tri-n-butylphosphine as a catalyst, then the mixture was heated to 60°C. After a reaction time of 4 hours, the NCO content of the reaction mixture was 40.4%, corresponding to an oligomerization level of 18.0%. The reaction was terminated by adding 2.8 g (0.015 mol) of methyl p-toluenesulfonate and heating to 80° C. for 1 hour. Thin-layer distillation at a temperature of 130° C. and a pressure of 0.15 mbar yielded a colorless polyisocyanate containing uretdione groups with an NCO content of 21.4%, a monomeric HDI content of 0.07%, and a viscosity (according to DIN 53 018) is 185 mPas (23°C).

[0067]For comparison, HDI polyisocyanate was prepared in a similar manner, but without N,N-diethylurea. Thin-layer distillation at...

Embodiment 2-8

[0071] implement

Embodiment 9

[0073] In 1000g (4.50mol) of isophorone diisocyanate (IPDI), at room temperature and under the protection of dry nitrogen, add 2g (0.2%) N, N-diethylurea as a stabilizer and 10g (1.0% / 0.05 mol) tri-n-butylphosphine as catalyst, which was then stirred for 40 hours until the NCO content of the reaction mixture had dropped to 32.9%, corresponding to an oligomerization level of 11.9%. The reaction was terminated by adding 9.3 g (0.05 mol) of methyl p-toluenesulfonate and heating to 80° C. for half an hour. Thin-layer distillation at a temperature of 160 °C and a pressure of 0.15 mbar yielded a highly viscous, pale yellow uretdione polyisocyanate with an NCO content of 17.2% and a monomeric IPDI content of 0.24%.

[0074] For comparison, IPDI polyisocyanate was prepared in a similar manner but without N,N-diethylurea. The pale yellow resin obtained after thin-layer distillation had an NCO content of 17.3% and a monomeric IPDI content of 0.27%.

[0075] Both polyisocyanates were s...

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Abstract

The invention relates to a process for the production of uretdione polyisocyanates with improved storage stability and their use as a starting component for polyurethane plastics, in particular as a crosslinker component for the production of two-component polyurethane coating compositions.

Description

technical field [0001] The present invention relates to a process for the preparation of uretdione polyisocyanates and to coating compositions and polyurethane plastics containing these uretdione polyisocyanates. Background technique [0002] The preparation of polyisocyanates having uretdione groups by catalytic dimerization and optionally simultaneous trimerization (commonly known as oligomerization) of monomeric aliphatic or cycloaliphatic diisocyanates is known. The advantages and disadvantages of various dimerization catalysts or catalyst systems are thoroughly discussed in the literature (cf. e.g. J. Prakt. Chem. 336 (1994) 185-200, EP-A 569 804, EP-A 572 995, EP-A A 645 411, EP-A 780 377, US-A 5 315 004, US-A 5 461 135, WO 97 / 45399 and WO 99 / 07765). [0003] Tertiary phosphines such as tributylphosphine are the most important dimerization catalysts for preparing light-colored polyisocyanates containing uretdione groups on an industrial scale. The prepared polyisocya...

Claims

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Application Information

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IPC IPC(8): C07D229/00C07D251/34C08G18/02C08G18/08C08G18/79
CPCC08G18/798C08G18/089C08G18/027
Inventor H·-J·拉尔斯R·哈尔帕普D·马格
Owner BAYER AG
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