Flexible mat for absorbing liquids comprising polymeric foam...

Details Flexible mat for absorbing liquids comprising polymeric foam... Flexible mat for absorbing liquids comprising polymeric foam...

1998-11-12

2001-06-12

Copenheaver, Blaine (Department: 1771)

Fabric (woven, knitted, or nonwoven textile or cloth, etc.)

Nonwoven fabric

Including a foamed layer or component

C428S304400, C428S319900

Reexamination Certificate

active

06245697

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates to a protective, flexible, absorbent mat which is used on floors and other surfaces.
BACKGROUND OF THE INVENTION
The protection of surfaces such as floors, carpets, rugs, furniture, upholstery and other surfaces is of significant commercial interest. Similarly of interest are examples wherein the direction of the protection is reversed, e.g., to protect an item or person from contamination by the environment. Protective coverings including films, towels, rugs and other woven or nonwoven fabrics both disposable and non-disposable have been widely used. Generally, these materials are not satisfactory in all respects. For example, many provide inadequate fluid absorbency and cannot soak up and retain spilled fluids. Others tear or abraid easily and generally lack the necessary mechanical strength for use. Still others are expensive and may require laundering and reuse. Some constructions lack sufficient stability when exposed to light, radiation, or certain chemicals which may further limit their utility.
Mats which contain a foam or cellular polymer, such as are described in “Polymer Foams”, ACS Symposium Series
669
, Khemani, K. C., Ed.; American Chemical Society, Wash., DC, 1997, are well known in the art. For example, U.S. Pat. No. 4,822,669 (Roga) issued Apr. 18, 1987, discloses a low cost absorbent mat having a top layer of nonwoven fiber laminated with a water impervious film and a bottom layer of polyurethane foam. The function of the foam in this instant appears to relate to providing a resilient mat for comfort reasons. The foam further provides a nonskid bottom surface. U.S. Pat. No. 45,028,468 (Taylor) issued Jul. 2, 1991 discloses a surgical mat with disposable cover for use in an operating room having a resilient or foam material to reduce fatigue of the user. U.S. Pat. No. 5,658,637 (Volz) issued Aug. 2, 1995 discloses a slip-resistant washable floor mat suitable for use in motor vehicles 1995 discloses a slip-resistant washable floor mat suitable for use in motor vehicles having a layer of coarse-celled polyurethane foam. Other similar references include U.S. Pat. No. 3,856,610 (Bruneel) issued Dec. 24, 1974, U.S. Pat. No. 4,421,809 (Bish et al.) issued Dec. 20, 1983, U.S. Pat. No. 4,143,194 (Wihksne) issued Mar. 6, 1979, U.S. 4,285,075 (Nelson) issued Aug. 15, 1981, and U.S. Pat. No. 4,609,580 (Rockett et al.) issued Sep. 2, 1986. The citations in this paragraphs are all incorporated herein by reference.
The use of an absorbent foam in such an article would be useful in that it could both provide for absorbency of contacted (spilled) liquids while also conferring a cushioning benefit. This could further extend the utility of such mats to include spill wipe up in addition to protection. Articles containing absorbent foams are also known. One type of absorbent foam is prepared by polymerizing High Internal Phase Emulsions (hereafter referred to as “HIPEs”). Such foams (hereinafter referred to as HIPE foams) are described in, for example, U.S. Pat. No. 5,260,345 (DesMarais et al.) issued Nov. 9, 1993, U.S. Pat. No. 5,268,224 (DesMarais et al.) issued Dec. 7, 1993, U.S. Pat. No. 5,387,207 (Dyer et al.) issued Feb. 7, 1995, and U.S. Pat. No. 5,650,222 (DesMarais et al) issued Jul. 22, 1997, (each of which is incorporated herein by reference). Absorbent articles made using such HIPE foams for mopping up household spills are known in the art and include U.S. Pat. No. 4,606,958 (Haq et al.) issued Aug. 19, 1986. Surgical drapes and bandages can also be formed from HIPE-foams modified to absorb blood, as described in U.S. Pat. No. 5,795,921 (Dyer et al.) issued Aug. 18, 1998. HIPE-foams offer the advantage of high absorbent capacity and fluid retention. However, these foams are typically not durable enough to be used alone and must be incorporated in a substrate or other non- polymeric foam material to be of benefit. application Ser. No. WO 99/46319 published in the name of DesMarais, et al on Sep. 16, 1999. discloses a version of these HIPE foams having extraordinary toughness and strength relative to previous versions. Absorbent foams other than HIPE foams are well known in the art. However, such foams lack the necessary fine microstructure to hold fluids effectively. Mats made using such foams, for example, polyurethane foams, will drain if lifted in a vertical position. Further, polyurethane foams are not sufficiently stable with respect to exposure to light to be universally useful without unsightly yellowing.
SUMMARY OF THE INVENTION
The present invention encompasses a flexible mat for absorbing liquids for use on floors and other surfaces comprising:
a) a waterproof backing layer or treatment;
b) a HIPE foam sheet formed by polymerization of water-in-oil emulsion having:
1) an oil phase comprising:
a) from about 85 to about 98%, by weight of the oil phase, said monomer component comprising:
i) from about 45 to about 70%, by weight of the monomer component, of a substantially water-insoluble, monofunctional monomer capable of forming a homopolymer having a Tg of about 25° C or less;
ii) from about 25 to about 45%, by weight of the monomer component, of a substantially water-insoluble, monofunctional comonomer capable of imparting toughness about equivalent to that provided by styrene;
iii) from about 3 to about 25%, by weight of the monomer component, of a first substantially water-insoluble, polyfunctional crosslinking agent selected from the group consisting of divinylbenzenes and analogs thereof;
iv) from 0 to about 15%, by weight of the monomer component, of a second substantially water-insoluble, polyfunctional crosslinking agent selected from the group consisting of polyfunctional acrylates, methacrylates, acrylamides, methacrylamides, and mixtures thereof;
v) wherein the weight ratio of the monofunctional comonomer capable of imparting toughness (ii) to the sum of the first and second polyfunctional crosslinking agents (iii+iv) is at least about 1:1;
b) from about 2 to about 15%, by weight of the oil phase, of an emulsifier component which is soluble in the oil phase and which is suitable for forming a stable water-in-oil emulsion; and
2) a water phase comprising from about 0.1 to about 20%, by weight of the water phase, of a water-soluble electrolyte; and
3) a volume to weight ratio of water phase to oil phase of at least about 12:1.
The mats can optionally contain optional components such as at least one liquid pervious sheet, and a non-skid material.
All percentages, ratios and proportions herein are by weight, unless otherwise specified. All documents cited are, in relevant part, incorporated herein by reference.


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