Fire Retardant Carpet

Abstract

A carpet in which the pile fibers are fixed to the primary backing by a compound comprising a latex binding material combined with an aluminum hydrate. The compound may be placed on the primary backing with sufficient thickness so that when the secondary backing is applied, no air pockets exist between the backings. Pressure rollers and/or a wetting or dispersion agent may be used to ensure that the primary backing is permeated by the compound.

Description

BACKGROUND OF THE INVENTION

When carpeting is manufactured, the fibers or pile are tufted on an interwoven primary backing which may be manufactured from any suitable materials such as jute or a man-made fiber. The non-wear side of the backing is then coated with a bonding material of any suitable type such as latex. The latex serves to satisfactorily hold the fibers in place so that they cannot be pulled free from the primary backing and also to bond the primary backing to the secondary backing. In the past, clay has been added to the latex as a filler so as to reduce the cost of the bonding compound.

It has long been thought desirable to apply only enough of the compound to the primary backing to hold the fibers in place and bond the secondary backing to the primary backing while preventing the compound from passing through either of the backings. If excessive bonding material penetrates the primary backing, an unacceptable visual effect is thought to be evident and the finished product is unusually hard to the touch. Excessive permeation of the bonding material through the secondary backing causes displacement of the bonding material from between the primary and secondary backings and this, in turn, may result in poor adhesion of the secondary backing to the carpet.

An interwoven secondary backing, which may also be jute or artificial fiber, is then placed in contact with the bonding compound. The secondary backing strengthens the carpet and ensures that the compound does not come into contact with the floor upon which the carpet is laid, since the latex would otherwise tend to wear and the carpet would deteriorate.

Unfortunately, carpeting formed in this manner produces an acceptable product insofar as comfort and visual effects are concerned but it is highly inflammable and possesses neither fire resistant nor fire retardant properties.

In view of many disastrous fires in which carpeting has been found to have caused death through burning and/or asphyxiation, investigations have been undertaken to produce carpeting which is either non-inflammable or fire retardant.

SUMMARY OF THE INVENTION

The present invention relates to a fire retardant carpeting which significantly reduces the amount of combustion which the carpet will undergo when heat or flame is applied thereto.

In carpets formed in accordance with the present invention, the bonding compound which is utilized to hold the fibers and secondary backing includes latex and a hydrate filler. The hydrate serves not only to reduce the cost of the bonding material by acting as a filler, but also provides the carpeting with fire retardant properties which significantly reduce the inflammability of the carpet.

When a bonding compound employing an aluminum hydrate is utilized, it has been found that a ratio of approximately 1 part of latex to 3.75 parts of the aluminum hydrate, by weight, will produce highly satisfactory fire retardant characteristics in the carpeting.

It has also been discovered that it is highly desirable to have the bonding compound permeate and at least slightly penetrate the primary backing so as to prevent flames and heat from reaching the backing without first contacting the compound. It has been found that the slight penetration of the bonding compound does not alter the visible effect substantially and the texture or "feel" of the carpet is unchanged.

In order to ensure that the compound permeates the primary backing, it may be applied thereto by means of pressure rollers which force it through the openings in the backing weave. Alternatively, a wetting or dispersion agent may be intermixed in the compound in order to decrease the surface tension of the compound so that it will flow through the holes in the backing at a predetermined rate. Further, the compound is applied in sufficient quantities so that when the secondary backing is pressed thereagainst, no air pockets are formed between the backings.

If an aluminum hydrate is used, it may be added, in powder form, to a liquid form of latex and mixed therewith in any suitable manner. Although a weight ratio of approximately 1 to 3.75 of latex to aluminum hydrate has been found desirable, other ratios may be employed, depending upon the adhesion capability of the latex, the degree of fire retardance necessary, usage of other hydrates, economic factors, etc. For example, it is possible that ratios within the range of 1 to 2 to 1 to 4.5 may prove to be suitable, depending upon the selection of the above enumerated factors.

When both backings are in place, the carpeting may be passed through an oven which may be set at a predetermined temperature, so that the bonding compound may be cured to prevent separation of the portions of the carpet. If the heat applied to the carpeting is less than the temperature than which the hydrate breaks down, no reaction will be experienced by the bonding material other than curing of the latex. When the carpet reaches a temperature equal to that of the hydrate breakdown temperature due to the application of flame or heat thereto, the hydrate will prevent the rapid spreading of fire since it is an inert material and since the breakdown thereof will release the molecular water contained therein. The water will cool the primary and secondary backings and prevent a rapid burning thereof.

Other advantages, objects, modes and embodiments of this invention will become obvious to those skilled in the art by reference to the Detailed Description and accompanying drawing which illustrate what is presently considered to be a preferred embodiment of the best mode contemplated for utilizing the novel principles of the invention as set forth in the claims.

BRIEF DESCRIPTION OF THE DRAWING

The FIGURE illustrates a partial cross section of a carpet utilizing the bonding filler of the present invention.

DETAILED DESCRIPTION

Referring now to the drawing in greater detail, there is shown an interwoven primary backing 11 which may be formed from jute or other material such as a man-made fiber. The backing comprises a first series of parallel fibers which are interwoven with a second series of parallel fibers, the two series extending at right angles to one another. Carpet pile fibers 13 extend through the primary backing 11 on the wear-side of the carpet and are held in place by being tufted through the backing.

A secondary backing 15 is suitably attached to the primary backing 11 by a bonding compound 17 which also serves to hold the threaded portions of the fibers 13 in fixed positions relative to the primary backing.

The compound 17 may be formed of a suitable mixture of latex and a hydrate material and is of sufficient quantity to satisfactorily bond the backing 11 to the backing 15. Further, the compound permeates the primary backing in an amount dependent upon the fiber material, the quality of the carpet, and the degree of flame retardance desired. Any suitable means such as a pressure roller application of the compound to the backing or the use of a suitable wetting agent, which decreases the surface tension of the binder, will cause it to flow through the holes between the two series of fibers.

Although it is possible that any suitable hydrate may be used with the latex in the bonding compound, it has been found that an aluminum hydrate will produce the desired effect in a very satisfactory manner if proper material ratios are utilized. For example, it has been determined that if either aluminum hydroxide, Al(OH).sub.3, or hydrated aluminum oxide, Al.sub.2 O.sub.3.sup. . 3H.sub.2 O, are used, a binding compound having a latex-hydrate weight ratio of 1 to 3.75 will produce a fire retardant carpet. As previously stated, this ratio may be varied within a predetermined range such as 1:2 to 1:4.5, not only for this selection of binder compound materials, but also for other binders, the degree of fire retardance desired, the bonding capacity of the latex, economic factors, quality and hardness of carpet, etc.

The carpeting is then passed through an oven at a temperature below the breakdown temperature of the hydrate so that the latex may be cured and hardened to prevent the fibers and/or secondary backing from being separated from the primary backing. For example, if aluminum hydrate is used as the filler, the oven may be set at 275.degree. F to cure the latex without breaking down the hydrate.

If flame or heat is applied to the carpet, when the temperature thereof is sufficient to ignite the carpet, the aluminum hydrate will break down and retard the spreading of the flame through the carpet since it is an inert material and since a small amount of water will be formed by the release of molecules of water from the hydrate. The water will cool the backing, as well as a portion of the fibers, to a temperature below the combustion temperatures thereof.

With this invention, the applicant has provided a disclosure of an embodiment of a new and improved concept in the carpet art which yields a true advance in that art due to an increase in safety without changing the physical appearances or other characteristics of the carpet. Many modifications and alterations of the described embodiment will be obvious to those skilled in the art, without exceeding the purview of the invention as set forth in the following claims.

Claims

What is claimed is:

1. In a carpet having a relatively pliable primary backing through which pile fibers are tufted, the improvement comprising

a bonding substance comprising

a latex material and

a hydrate material selected from the group consisting of aluminum hydroxide and hydrated aluminum oxide, the ratio by weight of said hydrate to said latex material being within the range of 1:2 to 1:4.5, and said hydrate having a breakdown temperature which is higher than the curing temperature of said latex material, wherein

said bonding material extends to both sides of a plane which includes said primary backing and surrounds the bases of the fiber tufts at the locations from which they extend toward the carpet wear surface.