Polyurethane foams made with blowing catalyst compositions containing primary hydroxyl groups and high ethylenediamine backbones

Inactive Publication Date: 2006-10-19
AIR PROD & CHEM INC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The discovery that CFCs deplete ozone in the stratosphere has resulted in mandates diminishing CFC use.
If a catalyst promotes the blowing reaction to an excessive degree, much of the CO2 will be evolved before sufficient reaction of isocyanate with polyol has occurred, and the CO2 will bubble out of the formulation, resulting in a collapse of the polymerization mass and yielding foam of poor quality.
Again, poor quality foams which are characterized by high density, broken or poorly defined cells, or other undesirable features will be produced.
Tertiary amine catalysts generally are malodorous and offensive and many have high volatility due to their low molecular weight.
Release of tertiary amines during foam processing may present significant safety and toxicity problems, and release of residual amines from customer products is generally undesirable.
On the other hand, low vapor pressure / high molecular weight amine catalysts are expected to require very high catalyst usage due to their low nitrogen / carbon ratio, making the manufacturing cost too high.
Tertiary amine catalysts containing hydroxyl functionality can chemically bind into the urethane matrix during the polymerization reaction, thus limiting their release from the finish product.
In addition, because the primary alcohols described in the prior art are highly reactive with isocyanates, they tend to lose their catalytic activity too early in the polymerization process.
As a result, polyurethane foams produced using the primary alcohols described in the art have large voids and exhibit decreased demoldability.
Furthermore, large amounts of the catalyst compositions containing primary hydroxyl functionality are required to effectively catalyze the blowing reaction.

Method used

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  • Polyurethane foams made with blowing catalyst compositions containing primary hydroxyl groups and high ethylenediamine backbones
  • Polyurethane foams made with blowing catalyst compositions containing primary hydroxyl groups and high ethylenediamine backbones
  • Polyurethane foams made with blowing catalyst compositions containing primary hydroxyl groups and high ethylenediamine backbones

Examples

Experimental program
Comparison scheme
Effect test

example 1

Synthesis of N-[2-hydroxyethyl]-N,N′,N″,N′″,N′″pentamethyltriethylenetetramine

[0052] A sample of about 519 grams of commercially available triethylenetetramine (about 67 wt %) was charged into a one-liter stainless steel reactor equipped with a cooling and heating jacket, a stirrer, a syringe pump and FTIR. The amine was heated to about 50° C. and pressurized with approximately 50 psig nitrogen. Ethylene oxide (about 170 g) was slowly added to the mixture and the product was allowed to stir for approximately one hour after addition, until the reaction was finished. The product was collected (about 639 g) and distilled under vacuum (20 mm Hg) to remove any unreacted amine. The crude ethoxylated product was dissolved in isopropanol and placed in the reactor together with 5% palladium on a carbon catalyst. The reactor was pressurized with hydrogen and heated up to about 90° C. Formalin (37% formaldehyde in water) was slowly added while the hydrogen pressure was monitored. At the end o...

example 2

Synthesis of N-[2-hydroxypropyl]-N,N′,N″,N′″,N′″pentamethyltriethylenetetramine

[0053] A sample of about 500 grams of commercially available triethylenetetramine (about 67 wt %) was charged into a one-liter stainless steel reactor equipped with a cooling and heating jacket, a stirrer, a syringe pump and FTIR. The amine was heated to about 80° C. and propylene oxide (about 187 g) was slowly added to the mixture. The product was allowed to stir for approximately one hour after addition, until the reaction was completed. The product was collected and distilled under vacuum (20 mm Hg) to remove any unreacted amine. The product mixture was dissolved in methanol and placed in the reactor together with 5% palladium on carbon catalyst. The reactor was pressurize with hydrogen and heated up to about 90° C. Formalin (37% formaldehyde in water) was slowly added while the hydrogen pressure was monitored. At the end of the addition the reaction was kept at about 90° C. for approximately one hour...

example 3

Rate of Rise of Polyurethane Foams

[0054] Two foams were prepared. Foam A was prepared using the catalyst of Example 1 (a mixture comprising, in major part, N-[2-hydroxyethyl]-N,N′,N″,N′″,N′″pentamethyltriethylenetetramine) and Foam B was prepared using the catalyst of Example 2 (a mixture comprising, in major part, N-[2-hydroxypropyl]-N,N′,N″,N′″,N′″pentamethyltriethylenetetramine).

[0055] For each foam, the catalyst was added to about 192 g of the premix (described in Table 2) in a 32 oz (951 mL) paper cup. The formulation was mixed for about 10 seconds at about 6,000 RPM using an overhead stirrer fitted with a 2 inch (5.1 cm) diameter stirring paddle.

TABLE 2Premix Components (Example 3)ComponentPercent by WeightPolyol 150Polyol 250Water2.34Silicon surfactant0.75DABCO 33-LV ®0.25DABCO ® BL-110.10Crosslinker1.76

[0056] Toluene diisocyanate was added in an amount sufficient to produce a foam with an NCO index of approximately 100. The formulation was mixed well for about 6 seconds...

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Abstract

A method is provided for preparing polyurethane foams, which comprises contacting at least one organic isocyanate compound, at least one polyol, at least one blowing agent, and a tertiary amine catalyst composition. The catalyst composition has the general formula wherein R1, R2, and Y are, independently, an alkyl group having from one to three carbon atoms or —CH2CH2OH; Z is —CH2CH2OH; and n is an integer from 3 to 7, inclusive. Also provided is a method for catalyzing the reaction between at least one isocyanate compound and at least one active hydrogen-containing compound, such as a polyol and / or a blowing agent.

Description

BACKGROUND OF THE INVENTION [0001] The present invention relates to the use of hydroxyl-containing tertiary amines as catalysts for producing polyurethanes. [0002] Polyurethane foams are widely known and used in the automotive, housing, and other industries. Such foams are produced by reaction of a polyisocyanate with a polyol in the presence of various additives. One such additive is a chlorofluorocarbon (CFC) blowing agent which vaporizes as a result of the reaction exotherm causing the polymerizing mass to form a foam. The discovery that CFCs deplete ozone in the stratosphere has resulted in mandates diminishing CFC use. Production of water blown foams, in which blowing is performed with CO2 generated by the reaction of water with the polyisocyanate, has therefore become increasingly important. Tertiary amine catalysts are typically used to accelerate blowing, for example, the reaction of water with polyisocyanate to generate CO2, and gelling, for example, the reaction of a polyo...

Claims

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Application Information

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IPC IPC(8): C08J9/00
CPCC08G18/1825C08G2101/0083C08G2101/0008C08G2110/0083C08G2110/0008C08G18/18C08G18/28C08J9/08C08G18/4261C08G18/4252C08J2203/10C08J2205/06
InventorBURDENIUC, JUAN JESUSFREYBERGER, DOUGLAS P.
OwnerAIR PROD & CHEM INC