US20020069448A1

US20020069448A1 - Evaporative cooling article

Info

Publication number: US20020069448A1
Application number: US09/870,550
Authority: US
Inventors: Michael Appolonia
Original assignee: Frisby Technologies Inc
Current assignee: Frisby Technologies Inc
Priority date: 2000-05-30
Filing date: 2001-05-30
Publication date: 2002-06-13

Abstract

Evaporative cooling material comprising three layers of nonwoven material. The innermost layer can be a breathable laminate, the central layer can be an absorbent material, and the outermost layer can be a wicking material that allows evaporative liquid to reach the central layer. The material can be used to fabricate garments such as vests, shorts and other articles such as blankets and compresses. The material is suited for use in hot conditions.

Description

This invention relates to cooling articles to be worn or placed on a person or animal and used as cooling garments, blankets, or compresses. More particularly, the invention relates to articles that employ the latent heat of vaporization to cool persons or animals.

BACKGROUND

Evaporative cooling vests are known in the art, as exemplified by the U.S. Pat. No. 5,885,912 to Bumbarger. Another example of such a garment is given in U.S. Pat. No. 5,263,336 to Kuramarohit. Other examples are provided in U.S. Pat. No. 5,755,110 to Silvas; U.S. Pat. No. 5,524,293 to Kung; and U.S. Pat. No. 4,856,294 to Scaringe et al.

SUMMARY

The invention results from the discovery that a novel combination of materials can be used to produce evaporative cooling articles that provide comfort under hot conditions. The article is of simple, elegant and cost-effective construction and can be made to be a limited-use disposable article, or a single use article.

As used herein, “liquid permeable” refers to the ability of a material to allow liquid to flow through it without the application of pressure greater than the weight of the liquid itself.

As used herein, “liquid impermeable” refers to the ability of a material to prevent the flow of liquid through it without the application of pressure greater than the weight of the liquid itself. As used herein, “vapor permeable” refers to the ability of a material to allow vapor to flow through it without the application of pressure more than 10% greater than standard atmospheric pressure. As used herein, “vapor impermeable” refers to the ability of a material to prevent vapor to flow through it without the application of pressure more than 10% greater than standard atmospheric pressure.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, suitable methods and materials are described below. All publications, patent applications, patents, and other references mentioned herein are incorporated by reference in their entirety. In case of conflict, the present specification, including definitions, will control. In addition, the materials, methods, and examples are illustrative only and not intended to be limiting.

Other features and advantages of the invention will be apparent from the following detailed description, and from the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross sectional view of a particular embodiment of the material used to produce evaporative cooling garments. [0008]
FIG. 2 is an evaporative cooling garment in the form of a vest. [0009]
FIG. 3 is a cross sectional view of another particular embodiment of the material used to produce evaporative cooling garments.[0010]

DETAILED DESCRIPTION

The evaporative cooling material has three distinct layers. The first layer next to the wearer's body is a water-resistant breathable laminate, the central layer is an absorbent layer, and the outermost layer is a porous and strong material. Together, these materials form a garment that can be saturated with a cooling liquid, typically water, that keeps the wearer cool in hot conditions. FIG. 1 is a schematic illustration of material according to a particular embodiment of the invention. [0011] First layer 10 includes an innermost layer 12, which is most proximate the body of a wearer 2. First layer 10 also includes an outermost layer 16, and between these is a central layer 14. Second layer 20 includes polyhydroxylated material 22, and polymeric material 24. Third layer 30 is the outermost layer of the material. The material is described in more detail in the following sections.
The material is suitable for use as a garment, but can also be used to fabricate blankets, compresses and similar coverings. These items have utility in the area of heat-protective items, medical treatment, and recreational articles. The cooling arises from the known heat removed from a surface upon evaporation of a liquid from the surface. [0012]
First Layer [0013]
The first, innermost layer is closest to the wearer's body. This first layer is a unidirectional laminate layer which is strong, liquid resistant and breathable. Its function is to minimize contact of the cooling liquid with the wearer's body. It also permits vaporous moisture to pass from the wearer's body into the apparel. In preferred embodiments the first layer is a high-strength fabric. Optionally and desirably, the first layer is water-resistant and breathable on its inner surface, that is, the surface closest to the wearer's body. This layer can be a fabric layer which is non-woven. The first layer is adapted to allow vapor to be drawn into the interior of the material, but to substantially prevent liquid from traveling toward the wearer's body. In preferred embodiments, the first layer is a non-woven material, such as that made from a polymeric material. For example, the first layer can be a laminate of three layers, spunbonded polymeric material forming the outer surfaces of the laminate while the inner material is a meltblown polymeric material. Such laminate material can be made more or less liquid permeable, by methods known to those of skill in the art. The polymers found useful for the purposes of the first layer can be, for example, polypropylene, or polyester, for example polyethyleneterephthalate. A suitable material for use as the first layer is commercially available, for example, from Kimberly Clark, as SMS laminate. This material can be used at a density of from about 0.8 to about 2.0 ounces per square yard, preferably from about 1.0 to 1.5 ounces per square yard, and more preferably about 1.2 ounces per square yard. For purposes of tensile strength and abrasion resistance, material that tends to be denser can be more desirable. [0014]
Second Layer [0015]
The second layer is an absorbent layer that is adapted to be saturated with cooling liquid, for example with water. This layer will act as a reservoir and as the cooling liquid evaporates from this layer, heat is removed from the material of this layer and consequently, heat is removed from the wearer, and in hot conditions, comfort is achieved thereby. Desirably, the material in the second layer retains the cooling liquid even when under pressure, so that unlike a sponge, the cooling liquid is not as readily lost when pressure is applied. This layer also desirably absorbs the cooling liquid quickly so that charging the article is a simple and quick operation. Further, the material of the second layer desirably imparts a softness to the apparel, so that some mild impact protection is granted the wearer. This material can include an amount of a hydroxylated material that is able to contain relatively large volumes of water. For example, a cellulosic material or a starch-like material can be utilized. In particular embodiments, the material of the second layer includes a cellulosic material that is further bonded to a number of fibers of polymeric material, such as polyalkylene material. Desirably, the polymeric material is present in the form of thin fibers that are bonded to the cellulosic material in large number of locations, giving the material added strength. Cooling liquid is absorbed by the polyhydroxylated material. In preferred embodiments of the invention, the cooling liquid is water. In some embodiments, superabsorbent particles are not present in the absorbent layer. Superabsorbent particles are materials that are in the form of small solid pellets or beads when dry, and take the form of a greatly expanded (the particles expand from 50 to 300 times their size) gel when saturated. Such particles are made from, for example, polyacrylamide. Such particles can increase the complexity of production of the articles, and can further increase the time required to fully saturate the articles with cooling liquid. In other embodiments, superabsorbent particles are present in the second layer. Further desirably, the cellulosic material makes up from about 50% to about 95% of the absorbent layer, for example from about 60% to about 95%, preferably from about 70% to about 95%, more preferably about 80%. [0016]
Material that is suitable for use in the second layer of the apparel is commercially available, for example from Kimberly Clark, and known as coform material. Such material includes 60-85% dry laid pulp fibers that are bonded by fibers of polypropylene which make up the remainder of the material. This material is available in a number of densities. Preferred material is available in densities of from about 150 to about 500 grams per square meter, more preferably from about 200 to about 500 grams per square meter, or even more preferably, from about 250 to about 400 grams per square meter. This material is able to absorb approximately 2.8 to 3.5 pounds of water per square yard of material. [0017]
Third Layer [0018]
The third layer of material is the outermost layer of the articles according to the invention, and is a wicking material that allows the passage of cooling liquid into the absorbent layer. The third layer is desirably strong, abrasion resistant, comfortable and relatively liquid permeable. In some embodiments, the third layer is made of a spunbonded material, such as a spunbonded polymeric material. The material can be made in a number of densities. In particular embodiments, the material is used as the third layer in a density of from approximately 0.5 to 2.0 ounces per square yard. In preferred embodiments, the material density is from about 0.75 to about 1.5 ounces per square yard. In other embodiments, the third layer is made of a nonwoven laminate of three layers, substantially as described as desirable with respect to the first layer, but somewhat less liquid impermeable. FIG. 3 is a schematic diagram in which figure elements repeated from FIG. 1 have the same designation. [0019] Third layer 30 includes innermost layer 32, central layer 34 and outermost layer 36.
In some embodiments, the third layer is formed from long continuous fibers of a polymeric material such as polypropylene, or polyester. Material suitable for use as the third layer is commercially available, for example from Kimberly Clark, and is known as Spunbond. In other embodiments, the third layer is formed from SMS laminate from Kimberly Clark, at a density of from about 0.8 to about 2.0 ounces per square yard, preferably from about 1.0 to 1.5 ounces per square yard, and more preferably about 1.2 ounces per square yard. For purposes of tensile strength and abrasion resistance, material that tends to be denser can be more desirable. [0020]
The three layers of material described herein can be laminated together after their individual manufacture, or can be built up as a single article of manufacture. The material can further be quilted, by methods known to those in the art. Quilting of the material can substantially retard pooling of cooling liquid at the bottom of the article under the effect of gravity. In some embodiments, the second and third layers are quilted together in a horizontal fashion. [0021]
The material can be used to construct garments such as vests, shorts, hats, caps, neck wraps, bandanas, as well as blankets and compresses. FIG. 2 is an illustration of a particular garment constructed of the material described herein, in this case, a vest. [0022]

EXAMPLES

The following examples illustrate certain properties and advantages inherent in some particular embodiments of the invention. Generally, in the following examples, [0023]

Example 1

Evaporative Cooling Vest

An evaporative cooling vest made from a first layer of Kimberly Clark SMS material (1.2 ounces per square yard), a second layer of Kimberly Clark coform (300 grams per square meter), and a third layer of Kimberly Clark spunbond (1 ounce per square yard) was constructed. The vest contained 0.76 square yards of material. The vest when dried weighed 0.59 pounds. The vest was soaked with water and became saturated within 1 and a half to two minutes. After lightly wringing the vest to remove excess water, the vest had gained 2.3 pounds of water. [0024]

Example 2

Cooling Effect

Two 8 by 10 inch swatches of material were prepared: a swatch of the material as prepared in Example 1 and a comparison material manufactured by Aqua-Tex Industries (Huntsville, Ala.) known as Hydroweave®. Both materials were saturated with water and lightly wrung. The material was positioned against a sheet of polystyrene insulation with a temperature probe placed between the insulation and the innermost surface of the material, that is the surface meant to be placed next to the wearer's body. The experiment was carried out in a chamber heated to 100° F. at a humidity of approximately 50%, which was not controlled during the experiment. [0025]
The temperature of the material as described in Example 1 remained at 75° F. for approximately two hours and 25 minutes, at which time the water had essentially evaporated. [0026]
The temperature reached 100° F. (ambient temperature) at the time point of three hours. The Hydroweave material remained at 75° F. for two hours and 20 minutes and reached ambient temperature after four hours. Thus, the inventive material showed equivalent performance for almost two and a half hours. [0027]

Example 3

Comfort of Wearers

The evaporative cooling vest of Example 1 was worn by volunteers inside a climate controlled chamber which was established at 30%, 50% and 70% relative humidity at 90° F. During the test, the subjects walked for ten minutes, rested for ten minutes and walked for 10 minutes. Temperature probes were placed between the subjects bodies and the innermost surface of the vest. [0028]
Subjects noted the comfort of the vest, particularly when the humidity was less than 70%. Although the body attempts to regulate the temperature to approximately 92° F., the measured temperature was comfortably below 83° F. throughout the thirty-minute test for the subjects in 30% and 50% humidity. The subject at 70% humidity had a skin temperature that rose toward 88° F. only in the last five minutes of the test. [0029]

OTHER EMBODIMENTS

It is to be understood that while the invention has been described in conjunction with the detailed description thereof, the forgoing description is intended to illustrate and not limit the scope of the invention, which is defined by the scope of the appended claims. Other aspects, advantages, and modifications are within the scope of the following claims. [0030]

Claims

What is claimed is:

1. A material for evaporative cooling, said material comprising three layers of nonwoven material:

a first nonwoven layer which is liquid impermeable and vapor permeable;

a second nonwoven absorbent layer; and

a third nonwoven layer which is liquid permeable.

2. The material of claim 1, wherein said second layer absorbs at least about 1.0 pounds of water per square yard.

3. The material of claim 2, wherein said second layer absorbs at least about 2.0 pounds of water per square yard.

4. The material of claim 3, wherein said second layer absorbs at least about 2.8 pounds of water per square yard within two minutes.

5. The material of claim 1, wherein each nonwoven layer comprises a polymeric material.

6. The material of claim 5, wherein said polymeric material is a polyalkylene or polyester material.

7. The material of claim 6, wherein said polymeric material is polypropylene.

8. The material of claim 1, wherein said second layer comprises a polyhydroxylated material.

9. The material of claim 8, wherein said polyhydroxylated material is selected from cellulosic material, or starch material.

10. The material of claim 9, wherein said polyhydroxylated material is 60-80% of said second layer, by weight.

11. An evaporative cooling article comprising the material of claim 1.

12. The article of claim 11, wherein said article is a garment

13. The article of claim 12, wherein said garment is a vest.

14. The article of claim 11, wherein said article is a blanket.

15. A method of providing evaporative cooling to a subject, said method comprising providing an evaporative cooling article of claim 11, wherein said article further contains water, and contacting the subject with said water-containing article.