Polymeric foam containing alumina boehmite

a technology of polymer foam and alumina boehmite, which is applied in the field of polymer foam, can solve the problems of undesirable small cell size, economic unfavorable, and difficulty in manufacturing desirable thermally insulating polymerics, and achieve the effect of minimising interferen

Inactive Publication Date: 2012-02-02
VO VAN CHAU
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0011]The present invention solves one or more problems associated with providing a polymeric foam containing a thermally insulating additive that does not act as a nucleator as much as carbon black, graphite and TiO2 yet that allows for formation of closed cell foam while having minimal effect on the color of the polymeric foam and that minimally interferes with use of pigments in coloring the polymeric foam.

Problems solved by technology

However, each of these infrared attenuators creates challenges in manufacturing desirable thermally insulating polymeric foam.
Small cell sizes are undesirable in the process of making thermally insulating foam because small cell sizes lead to a high foam density, which becomes economically unfavorable.
A particle that has a size larger than the cell wall between to cells can cause rupturing of the wall between the cells and promote open cell structure throughout the foam, which is also undesirable for thermally insulating foam.
This can be undesirable if there is a desire to have a color other than black or grey because it is difficult to modify the color of black or grey foam much by addition of other pigments.
Carbon black and graphite become undesirable additives in these situations.
Moreover, titanium dioxide is such an efficient white pigment that it also makes it difficult to color foam to a particular non-white color because the TiO2 washes out the non-white pigment color.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

examples

Preparation

[0056]Control Foam

[0057]Prepare a control sample without any infrared attenuating agents by first dry blending 100 weight-parts of polystyrene resin composed of 80 wt % low Mw polystyrene (Mw=145,000 g / mol, Mw / Mn=3.3) and 20 wt % high Mw polystyrene (Mw=200,000 g / mol, Mw / Mn=2.7) with 0.1 weight parts barium stearate, 0.2 weight parts copper phthalocyanine blue pigment (in a 20 wt % concentrate in polystyrene) and 0.2 weight parts polyethylene and feed the blend in to a 50 millimeter (mm) extruder that heats the blend to 200° C. and mixes it thoroughly. While in the extruder, add a blowing agent consisting of 4 weight parts carbon dioxide and 1.5 weight parts iso-butane at a pressure that precludes foaming (13-25 megapascals for mixing) to form a foamable polymer composition. After blending the foamble polymer composition, reduce its temperature to approximately 127° C. and extrude it through a slit die into atmospheric pressure (101 kilopascals) and ambient temperature (2...

examples 1 and 2

[0062]Prepare Examples (Exs) in like manner as the Control Foam except:

Ex 1

[0063]In the dry blend include alumina boehmite having an average particle size of approximately 15 microns (for example, PURAL®-NF, PURAL is a trademark of Sasol Germany GmbH). Add the alumina boehmite into the dry blend as a compounded concentrate that is 80% polystyrene). Ex 1(i) contains 2.5 wt % alumina boehmite and Ex 1(H) contains 5 wt % alumina boemite.

Ex 2

[0064]In the dry blend include alumina boehmite having an average particle size of approximately 40 microns (for example, DISPAL® 25F4, DISPAL is a trademark of Sasol North America, Inc.). Add the alumina boehmite into the dry blend as a compounded concentrate that is 80% polystyrene). Ex 2(i) contains 2.5 wt % alumina boehmite and Ex 2(ii) contains 5 wt % alumina boemite.

Properties

[0065]Table 1 lists typical properties of the Control, Comp Exs and Ex. Determine density according to the method of ISO 845-95. Determine Open Cell Content according to ...

example 3

Nitrated Alumina Boehmite

[0071]Prepare Example 3 in like manner as Exs 1 and 2 with the following differences:[0072](1) Use as the alumina boehmite DISPERAL® P2 (from Sasol North America, Inc.), which has a nitrate concentration of 3.4 to 4.0 wt %.[0073](2) Use a 0.75 inch (20 millimeter) extruder;[0074](3) Use 3.5 pph carbon dioxide; and[0075](4) Omit the blue pigment.

[0076]At alumina boehmite concentrations of 4, 7 and 10 weight-parts all resulted in an undesirable decrease in cell size and an undesirable yellowing of the polymeric foam. The decrease in cell size and yellowing are likely a result of thermal degradation of the alumina boehmite during the foam manufacturing process. This Example illustrates why the nitrate concentration in the alumina boehmite is desirably 3.0 percent or less.

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PUM

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Abstract

Prepare a polymeric foam by expanding a foamable polymer composition comprising alumina boehmite.

Description

CROSS REFERENCE STATEMENT[0001]This application claims the benefit of U.S. Provisional Application No. 61 / 163,891, filed Mar. 27, 2009, the entire content of which is incorporated herein by reference.BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]The present invention relates to polymeric foam and a process for preparing polymeric foam.[0004]2. Description of Related Art[0005]Thermally insulating polymeric foam is commonplace in our world today. Thermally insulating polymeric foam sheets are available in most supply centers for implementation in structural building. Current energy costs and desires by consumers for more comfortable homes continually drive development of more desirable thermally insulating polymeric foams. One paramount driver is to reduce the thermal conductivity through polymeric foam.[0006]Inclusion of an infrared attenuator in polymeric foam is one means of decreasing thermal conductivity through the foam. Infrared attenuators in polymeric foam i...

Claims

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Application Information

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Patent Type & Authority Applications(United States)
IPC IPC(8): E04B1/78
CPCC08J9/0066C08J9/122C08J2325/06C08J2205/052C08J2201/03
Inventor VO, VAN-CHAU
Owner VO VAN CHAU
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