Composite polyurethane foams and method of manufacture thereof

Details Composite polyurethane foams and method of manufacture thereof Composite polyurethane foams and method of manufacture thereof

2001-06-27

2003-10-21

Cooney, Jr., John M. (Department: 1711)

Synthetic resins or natural rubbers -- part of the class 520 ser

Synthetic resins

Cellular products or processes of preparing a cellular...

C521S155000, C521S174000, C428S423300

Reexamination Certificate

active

06635688

ABSTRACT:

FIELD OF THE INVENTION
This invention relates to composite polyurethane foams and methods of manufacture thereof. In particular, this invention relates to a layered polyurethane foamed composite.
BRIEF DESCRIPTION OF THE RELATED ART
Composite, i.e., multiple-layer foamed polyurethane materials are known, and are often manufactured in order to obtain a combination of desirable properties. Such composites have primarily been manufactured by laminating the individual foam layers together, generally by using adhesives. These methods require additional manufacturing steps, and may result in materials with degraded, rather than improved properties.
A composite, dual layer polyurethane foam is disclosed in U.S. Pat. No. 5,859,081 to Duffy, wherein the composite is manufactured by casting an uncured (wet) polyurethane foam composition onto a cured (dry) polyurethane foam. It is admitted in Duffy that the dual layer foam has a “fine and uniform interface between the two layers” (col. 2, lines 59-60). However, such an interface line can interfere with air flow through the multilayer foam structure, reducing the breathability, porosity and water vapor transmission that are important for many applications. In addition, this interface can produce a location for delamination of the layers because it's strength depends on the adhesion of the second cast layer to the first.
It has also been found by the inventors that casting uncured wet polyurethane foam compositions onto a cured (dry) polyurethane open celled foam results in large voids and bubbles in the second layer, due to expansion of the gas in the cells of the first layer during the curing process. In addition to the cosmetic deficiencies of these voids and bubbles the physical properties can also be negatively affected during production and/or use.
Thus, there is a need for a product and a process to make a multilayer foam structure with no structural interface line between the layers.
SUMMARY
A method for the manufacture of multiple layer polyurethane foams, which comprises:
casting an uncured (wet) polyurethane foam onto a cast, uncured (wet) polyurethane foam; and
curing the resulting layers of foam such that the final product possesses no discernible structural interface line between the layers when examined at a magnification of 50× using a scanning electron microscope (SEM).
If the different layers have different colors then visible microscopy can be used to visualize the border region between layers. Multilayered foams of the present invention show evidence of polymer diffusion between the layers but the cells of the foam are distributed uniformly from one surface to the other without regard to the transition zone between the layers. Such multilayered foams cannot be delaminated, in that the tear strength of one of the layers is exceeded before any evidence of delamination is seen.


REFERENCES:
patent: 2602783 (1952-07-01), Simon et al.
patent: 2621166 (1952-12-01), Schmidt et al.
patent: 2729618 (1956-01-01), Muller et al.
patent: 2779680 (1957-01-01), Reis, Jr.
patent: 2808391 (1957-10-01), Pattison
patent: 2811493 (1957-10-01), Simon et al.
patent: 2833730 (1958-05-01), Barthel, Jr.
patent: 2834748 (1958-05-01), Bailey et al.
patent: 2846458 (1958-08-01), Haluska
patent: 2866744 (1958-12-01), Askey et al.
patent: 2870097 (1959-01-01), Brayton et al.
patent: 2877212 (1959-03-01), Seligman
patent: 2878601 (1959-03-01), Burmeister et al.
patent: 2901473 (1959-08-01), Steinemann
patent: 2911390 (1959-11-01), Smith et al.
patent: 2917480 (1959-12-01), Bailey et al.
patent: 2962524 (1960-11-01), Hastlettler
patent: 3021309 (1962-02-01), Cox et al.
patent: 3021310 (1962-02-01), Cox et al.
patent: 3021312 (1962-02-01), Cox et al.
patent: 3021313 (1962-02-01), Cox et al.
patent: 3021314 (1962-02-01), Cox et al.
patent: 3021315 (1962-02-01), Cox et al.
patent: 3021316 (1962-02-01), Cox et al.
patent: 3021317 (1962-02-01), Cox et al.
patent: 3057901 (1962-10-01), Plueddemann
patent: 3169945 (1965-02-01), Hostettler et al.
patent: 3201311 (1965-08-01), Antonides et al.
patent: 3383351 (1968-05-01), Stamberger
patent: 4101704 (1978-07-01), Hiles
patent: 4346205 (1982-08-01), Hiles
patent: 5034264 (1991-07-01), Wagner et al.
patent: 5420381 (1995-05-01), Gardner, Jr. et al.
patent: 5580501 (1996-12-01), Gallagher et al.
patent: 5604267 (1997-02-01), Duffy
patent: 5733945 (1998-03-01), Simpson
patent: 5747167 (1998-05-01), Greene
patent: 5859081 (1999-01-01), Duffy
patent: 5922781 (1999-07-01), St. Clair et al.
patent: 5973016 (1999-10-01), St. Clair et al.
patent: 5989699 (1999-11-01), Kuczynski et al.
patent: 6051624 (2000-04-01), Bastin et al.
patent: 733624 (1955-07-01), None
EAR Specialty Composites 1999 Aearo Company Printed 8/99.

Affiliated with

Also associated with

Rating

Composite polyurethane foams and method of manufacture thereof does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Composite polyurethane foams and method of manufacture thereof, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Composite polyurethane foams and method of manufacture thereof will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-3127222