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Process for producing a low density free-rise polyurethane foam

Inactive Publication Date: 2015-09-17
PROPRIETECT LP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

The present invention provides a new way to produce flexible polyurethane foam with a low density (less than or equal to 0.75 pcf) using molded polyols without using additional blowing agents or tin-based catalyst compounds. This is achieved by adding more water to the foam formulation to absorb the heat generated by the use of molded polyols and generate carbon dioxide as a blowing agent, resulting in a lower density foam with reduced shrinkage or collapse.

Problems solved by technology

If the blowing reaction occurs too quickly, the resulting growing foam does not have enough strength and collapses.
If the gel reaction occurs too quickly, the resulting foam will shrink during cooling.
In practice, once a threshold temperature is reached (typically up to 160° C. for most open cell flexible slabstock foams and up to 200° C. for most rigid, semi-rigid and low airflow slabstock foams), in the presence of air or oxygen, auto-oxidation of the foam may occur resulting in discoloration (product deterioration) and sometimes fire (damaging and / or destroying the manufacturing facility).
It has not been conventional to utilize molded polyols in the production of slabstock foams because such use can aggravate the exotherm problem described above.
Specifically, due to the relatively high reactivity of the molded polyols, there is a greater risk of increasing the exotherm of the reaction and contributing to the occurrence of the problems mentioned above.
These auxiliary blowing agents (particularly low boiling point liquids) are not friendly to the environment and their use increases the cost of foam production.
Foam production with auxiliary blowing agents is also more difficult and in some cases requires higher capital investment.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

examples 1-2

[0125]In these Examples, foam samples were produced pursuant to the formulations provided in Table 1 (all parts are parts by weight). The methodology used in each Example was as follows.

[0126]A resin mixture was produced by mixing all ingredients except the isocyanate in a 1 L mixing vessel for a period of approximately 10 seconds at 3000 rpm. Next, the isocyanate was added to the mixing vessel and the contexts were mixed for a further 5 seconds. The contents of the mixing vessel were transferred to an open (15″×12″×12″) and allowed to free rise. box The resulting foam was allowed to cure for at least 24 hours prior to testing.

[0127]Table 2 reports observations during production of the foam samples and properties of the resulting foams. These observations and properties illustrate that a good quality slab foam having very low density can be made using a high primary hydroxyl content polyol (normally used to produce molded foam) in the absence of added auxiliary blowing agents while ...

example 3

[0128]The methodology of Examples 1 was repeated using the formulation provided in Table 3 (all parts are parts by weight).

[0129]Table 4 reports observations during production of the foam samples and properties of the resulting foam. The positive results seen in Example 1 were also seen in Example 2 even when a mixture of polyols (i.e., a high primary hydroxyl content polyol and a high secondary hydroxyl content polyol) was used with a reactive (non-fugitive) catalyst system.

example 4

[0130]The methodology of Examples 1-2 was repeated using the formulation provided in Table 5 (all parts are parts by weight).

[0131]Table 6 reports observations during production of the foam samples and properties of the resulting foam. The positive results seen in Example 1 (re. low density) were also seen in Example 3 even when a mixture of polyols (i.e., a high primary hydroxyl content polyol and a high secondary hydroxyl content polyol), a mixture of isocyanates (i.e., TDI and MDI), a different surfactant and a different combination of catalysts.

[0132]While this invention has been described with reference to illustrative embodiments and examples, the description is not intended to be construed in a limiting sense. Thus, various modifications of the illustrative embodiments, as well as other embodiments of the invention, will be apparent to persons skilled in the art upon reference to this description. It is therefore contemplated that the appended claims will cover any such modif...

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Abstract

There is described a process for producing a free-rise polyurethane foam having a density of less than or equal to about 0.75 pcf. the the process comprises the steps of: (a) contacting: (i) an isocyanate, (ii) a first polyol comprising a first polymer chain consisting essentially of propylene oxide units and alkylene oxide units selected from ethylene oxide, butylene oxide and mixtures thereof in a weight ratio of propylene oxide units to alkylene oxide units in the range of from about 90:10 to about 25:75, the polymer chain being terminally capped with the ethylene oxide units, the first polyol having a primary hydroxyl content of at least about 70% based on the total hydroxyl content of the first polyol, (iii) water (iv) a surfactant and (v) a catalyst to form a foamable reaction mixture; and (b) expanding the foamable reaction mixture to produce the free-rise polyurethane foam.

Description

CROSS-REFERENCE TO RELATED APPLICATION[0001]The present application claims the benefit under 35 U.S.C. §119(e) of provisional patent application Ser. No. 61 / 795,075, filed Oct. 10, 2012, the contents of which are hereby incorporated by reference.BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]In one of its aspects, the present invention relates to a process for producing a free-rise polyurethane foam having a density of less than or equal to about 0.75 pcf. In another of its aspects, the present invention relates to a free-rise flexible polyurethane foam produced by this process. In yet another of its aspects, the present invention relates to a free-rise flexible polyurethane foam: (i) having a density less than or equal to about 0.75 pcf, (ii) having a low exotherm during production, and (iii) being substantially completely free of metal-containing catalyst[0004]2. Description of the Prior Art[0005]Isocyanate-based polymers are known in the art. Generally, those of ...

Claims

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Application Information

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IPC IPC(8): C08G18/08C08G18/76C08G18/48C08G18/20C08G18/18
CPCC08G18/14C08G18/2063C08G18/1833C08G18/1825C08G2101/0008C08G18/7621C08G18/7671C08G2101/0083C08G18/4883C08G18/6677C08G18/7664C08G2110/0083C08G2110/005C08G2110/0008
Inventor ZHANG, JINGULMAN, DORATA
Owner PROPRIETECT LP