Unlock instant, AI-driven research and patent intelligence for your innovation.

Mixable room temperature castable polyurethane system

Inactive Publication Date: 2002-09-12
UNITED TECH CORP
View PDF0 Cites 1 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0007] Accordingly, it is an object of the present invention to provide a polyurethane compound which has improved quality, manufacturing properties and adhesive strength.
[0010] It is yet a further object of the present invention to provide a polyurethane compound as above which can be packaged without the introduction of air.
[0012] In accordance with the present invention, a polyurethane compound or system is provided which contains a formulation of polyurethane prepolymers mixed with an aromatic amine curing agent in a volumetric mix ratio of from about 0.9:1 to about 1:1. The formulation of polyurethane prepolymers consists of a blend of different polyethers based on diphenylmethane diisocyanate. The aromatic amine curing agent preferably comprises a blend of oligomeric diamines and an aromatic diamine with a catalytic component. Both of the blends, when in an uncured state, are liquid at room temperature. Polyether type prepolymers are important for moisture and solvent resistance. Polyurethane based MDI prepolymers are important for health and safety reasons, for being liquid at room temperature, and for offering better adhesion properties. Aromatic amine curing is important for best thermal stability and moisture resistance.

Problems solved by technology

Currently available polyurethane potting materials suffer from a number of deficiencies.
For example, some are difficult to process, resulting in high rework and / or poor yield.
Others contain hazardous materials which require special handling procedures and which can not be used at all at many manufacturing facilities.
The compound is difficult to work with, as it requires heating of the resin above 180 degrees Fahrenheit and melting of the hardener above 300 degrees Fahrenheit, before mixing.
The entrapped air bubbles are cause for vane assembly rejection / rework.

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • Mixable room temperature castable polyurethane system
  • Mixable room temperature castable polyurethane system
  • Mixable room temperature castable polyurethane system

Examples

Experimental program
Comparison scheme
Effect test

example i

[0029] To illustrate the improvements created by the polyurethane compound of the present invention, the following example was performed. A formulation of polyurethane prepolymers and a formulation of aromatic amine curing agent in accordance with the present invention were prepared. The polyurethane prepolymer formulation and the aromatic amine curing agent formulation were mixed in a 1:1 ratio and injected through a mixing nozzle at room temperature into a trench in a support structure holding a trial vane. Eleven trial vanes were potted with this polyurethane compound system. Examination of these vanes showed that there was a very low level to no indication of entrapped air. Further, these parts successfully met dimensional and pull test requirements and the polyurethane compounds met or exceeded all requirements as shown in Table 1.

1TABLE 1 PWA 597 Specification Test PWA 597 Requirement P&W Formulation As received material Tensile Strength (psi) 4000 Min. 4230 Elongation (%) 400...

example 2

[0033] In addition to the above example, a test was conducted using a polyurethane compound prepared in accordance with the present invention. The formulation was tested on 4 vane assemblies with 1 vane humidity exposed and 1 vane thermally exposed at 140.degree. F. / 95%RH / 14.5 days and 250.degree. F. / 14.5 days respectively. These vanes tested at 1900 pounds and 3500 pounds. The 2 baseline vanes tested at 2600 and 2700 pounds.

[0034] The FEGVs (Fan Exit Guide Vanes) used for the above tests all passed visual and dimensional requirements of the potting operation.

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

PUM

PropertyMeasurementUnit
Fractionaaaaaaaaaa
Fractionaaaaaaaaaa
Fractionaaaaaaaaaa
Login to View More

Abstract

The present invention relates to a polyurethane compound which has particular utility as a potting compound for fan exit guide vane assemblies of commercial gas turbine engines. The polyurethane compound comprises a formulation of polyurethane prepolymers mixed with an aromatic amine curing agent (hardener) in a volumetric mix ratio in the range of from about 0.9:1 to about 1:1. The polyurethane prepolymer consists of a blend of different polyethers based on diphenylmethane diisocyanate (MDI). The amine curing agent is a blend of oligomeric diamines with an aromatic diamine with a catalytic component. Both of the blends, in an uncured state, are liquid at room temperature.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001] This is a continuation-in-part application of U.S. patent application Ser. No. 09 / 222,090, entitled A MIXABLE ROOM TEMPERATURE CASTABLE POLYURETHANE SYSTEM, filed Dec. 29, 1998.BACKGROUND OF THE INVENTION[0002] The present invention relates to an improved polyurethane compound which has utility as a potting compound in fan exit guide vane assemblies of commercial gas turbine engines.[0003] Polyurethane compounds have been used as potting compounds in fan exit guide vane assemblies of commercial gas turbine engines. Currently available polyurethane potting materials suffer from a number of deficiencies. For example, some are difficult to process, resulting in high rework and / or poor yield. Others contain hazardous materials which require special handling procedures and which can not be used at all at many manufacturing facilities.[0004] One polyurethane compound which has been used is one from a company named Jonal. The compound is diffic...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

Application Information

Patent Timeline
no application Login to View More
IPC IPC(8): C08G18/00C08G71/04C08G18/10C08G18/65C08G18/66C08G18/76F02C7/00F04D29/54
CPCC08G18/10C08G18/7664C08G18/3237C08G18/00
Inventor PUTNAM, JOHN W.BERNAT, LAURENCE E.WESSON, JOHN P.VONTELL, JOHN H.
Owner UNITED TECH CORP