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Blocked 1,8-diazabicyclo[5.4.0]undec-7-ene bicarbonate catalyst for aerospace sealants

A technology of diazabicyclo and bicarbonate, which is applied in the direction of adhesive heating bonding method, adhesive, adhesive type, etc., and can solve problems such as damage to the performance of polymer fuel resistance

Active Publication Date: 2018-08-03
PRC DE SOTO INT INC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the components that form the encapsulant, are incorporated into the cured polymer network, which compromises properties of the cured polymer, such as fuel resistance

Method used

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  • Blocked 1,8-diazabicyclo[5.4.0]undec-7-ene bicarbonate catalyst for aerospace sealants
  • Blocked 1,8-diazabicyclo[5.4.0]undec-7-ene bicarbonate catalyst for aerospace sealants
  • Blocked 1,8-diazabicyclo[5.4.0]undec-7-ene bicarbonate catalyst for aerospace sealants

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0186] Synthesis of DBU Bicarbonate Catalyst

[0187] Into a 2,000-mL, 4-neck flask equipped with a stirrer, condenser, nitrogen inlet, and thermocouple were combined 50.6 g of DBU (technical grade, from BASF), 6.66 g of distilled water, and 300 g of ethyl acetate. Fifty (50) g ​​of dry ice was partially added to the reaction mixture and a white precipitate formed. After complete addition of dry ice, the reaction mixture was kept at room temperature for 1 h. The white solid was collected by filtration. The solid was then washed twice with ethyl acetate (3 x 50 mL) and dried in a vacuum oven. A white powder was obtained in a yield of 97% by weight. 1% by weight fumed silica was added to the white solid and mixed. The mixed solids were ground into a fine powder (75 μm) using an air classifier (ACM) manufactured by MIKRO.

Embodiment 2

[0206] Sealant Formulation

[0207] The sealant formulation of the present invention consists of two parts, a base and an accelerator. The base formulation is shown in Table 4, while the accelerator formulation is shown in Table 5.

[0208] Table 4. The basic formula of embodiment 2

[0209]

[0210]

[0211] *Adhesion Promoter, available from PRC-DeSoto International, Inc.

[0212] **thiol-terminated polythioether prepolymer available from PRC-DeSoto International, Inc.

[0213] The base components were mixed well and the composition was kept at room temperature for 24 hours before mixing with the accelerator.

[0214] The accelerator formula of table 5. embodiment 2

[0215]

[0216] *T-1601 Adhesion Promoter, available from PRC-DeSoto International, Inc.

[0217] The accelerator components were mixed well and the composition was kept at room temperature for 24 hours before mixing with the base formula.

[0218] The sealant was prepared by mixing 100 g of the ...

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PUM

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Abstract

Compositions comprising sulfur-containing prepolymers such as polythioether prepolymers, polyepoxides, and a blocked 1,8-diazabicyclo[5.4.0]undec-7-ene bicarbonate catalyst useful as aerospace sealants are disclosed. The compositions exhibit extended working time and the curing rate can be tailored for specific applications.

Description

technical field [0001] The present disclosure relates to compounds comprising sulfur-containing prepolymers such as thiol-terminated polythioether prepolymers, polyepoxides, and blocked 1,8-diazabicyclo[5.4.0]undec-7-ene bicarbonates Compositions of Salt Catalysts. The compositions are useful in aerospace sealant applications, which exhibit extended processing times and provide controlled cure rates. Background technique [0002] Aerospace sealants must meet demanding mechanical, chemical and environmental requirements. The sealer can be applied to a variety of surfaces including metal surfaces, primer coats, intermediate coats, finished coats and aged coats. Sealants comprising sulfur-containing prepolymers that exhibit acceptable fuel resistance, heat resistance, and flexibility for aerospace applications are described, for example, in US Patent No. 6,172,179. In sealants such as those described in U.S. Application Publication Nos. 2006 / 0270796, 2007 / 0287810, and 2009 / 0...

Claims

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Application Information

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IPC IPC(8): C08G16/00C08K5/00C08G75/02C08L81/00C08L81/02
CPCC08G16/00C08G75/02C08L81/00C08L81/02C08L63/04C08G59/686C09J5/06C09J163/00C09J163/04C09J2463/00
Inventor 周宏英蔡觉晓林仁和
Owner PRC DE SOTO INT INC