BACKING FOR CARPET

INVENTORS: Kenneth R. Jones Terry Crump

BACKGROUND OF THE INVENTION

I. Field of the Invention

The present invention relates generally to the manufacturing of carpet for use in a variety of applications, and more specifically to products and methods which embody an improved primary backing. π. Background and Prior Art

A tufted carpet is manufactured by inserting needles with yarn through a primary backing. The yarn loops can be either cut or uncut which creates different face finishes. This primary backings is considered to be the foundation for the end product since its properties can directly influence the physical stability of the product and the quality of its appearance. The most common primary backing used today in the carpet manufacturing process is a woven polypropylene. In the synthetic turf industry there have been many attempts to alleviate specific problems unique to the industry with respect to the installation and performance of the final product. One area of concern is the stability of the finished product when exposed to climatic changes, such as from wet to dry and from hot to cold. These issues, which present uncertainties in the quality of the installed surface, have been addressed by some manufacturers by using multiple primaries, such as using two woven primaries made of polypropylene. Others have used three, four and even five primaries to offset potential end-use problems. Still, other

which have been made of woven, non-woven in combination, along with the primaries made with polyester, fiberglass and polypropylene.

In most instances, these multiple primaries did offer some retardation of expansion and contraction when exposed to climatic changes. However, the notion of implementing multiple primaries of different polymers has caused several problems to arise in the manufacturing process.

First, multiple primaries are very hard to feed simultaneously through a tufting machine. Second, multiple primaries, if there were variations in construction (woven and non-woven) would not only feed into the tufting machine in different manners, but they would react in different ways. For example, a woven polypropylene would be easier to manipulate while a non- woven polyester would tend to crease or wrinkle. Third, the use of non-woven materials may create a condition known as "stitch lock." Stitch lock is when the tufting needle, upon penetration of the primary material with the yarn, cannot exert enough of a force around the tufted yarn, thereby resulting in loose tufts which are subject to being pulled out during the manufacturing process .

Fourth, multiple primaries were harder to pin in the coating process when applying the adhesive coating for stitch lock. A conventional curing oven carries the greige and the coated fabric through the process by a tenter. A tenter is a chain with a series of pins which protrude into the primary and help carry the product through the coating process. It can be difficult, and in some cases almost impossible, to pin two and three primaries. In some instances the primaries are of different widths making it impossible to pin at all.

Fifth, another problem with multiple primaries was that the adhesive layer would only coat the back of the stitch and the primary backing in direct contract with the adhesive. This left

the This did not constitute as much of a problem if the end product was unfilled with a particulate such as sand or tire rubber or both. In fact, in some instances it became a positive since the additional primary or primaries were a buffer and protectorate for the abrasive nature of the infill. Finally, the use of multiple primaries could be considered a negative, because of the common practice of making drainage holes into the finished product, particularly in the case of synthetic turf for sports applications. For example, the hole punching technique generally requires puncturing and burning simultaneously, leaving holes approximately one quarter inch in diameter and at approximately four inch centers. The process can become increasingly difficult, depending on the amount of and make-up of the primary structure.

Therefore, a need existed to develop a primary backing which would address each of the issues stated. The ideal primary would have the following features: (1) a single substrate for ease in the tufting and coating process, (2) the stitch lock characteristics of a woven material, (3) the dimensional stability that a fiberglass would have, and (4) the physical strength to stand up to the rigors of functional playing surface and dimensional stability for the climatic conditions.

IP C T/ IJl S O B / i$*POT#RY ^{OF χ} HE INVENTION

Therefore, one object of the present invention is to provide an improved primary backing material for carpets which is stronger than existing products.

It is also an object of the present invention to provide an improved primary backing material for carpets which retains its dimensional stability.

A further object of the present invention is to provide an improved primary backing material for carpets which comprise a single substrate.

Accordingly, an improved primary backing material for carpets is provided, comprising a single substrate backing having a plain or modified plain weave; a warp having a low shrinkage primary warp yarn, a first secondary warp yarn with characteristics sufficient to reduce static electricity, and a second secondary warp yarn constructed from a fiberglass material; and a weft having a low shrinkage primary weft yarn, and a first secondary weft yarn constructed from a fiberglass material.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A series of synthetic turf samples were produced for testing. Each product was constructed in the identical manner, except the primary backings. Although not every combination of primary construction was accomplished, the most common combinations were employed using the following basic parameters: Gauge Machine: Three Eighth

Type Yarn: Polyethylene Fiber

Pile Height: 2 inches

Stitches per Inch: 4

Samij(le|jl;;l'\/χ|ιg®^|ipf®t^φ!M-^ backing in accordance with the present invention.

Sample 2: CO8 Primary Sample 3 : SI Primary Sample 4: Single woven polypropylene Sample 5: Two woven polypropylene

Using the above described samples, the samples were each tested in accordance with the following descriptions.

1. Tufting process: All test samples were very similar in the tufting process except for the double primary, which required more care and attention to feeding like two primaries and maintaining straightness.

2. Stitch lock around the yarn from the woven primary or primaries was good, but the improved primary backing in accordance with the present invention is notably better.

3. The adhesive coating of the polyurethane pre-coat process was the same on all samples. The weight of the adhesive was the same, but the overall visual look was different because of the primary composites (visual only) .

4. Hole punching was similar with no negatives noted as far as resistance to punching and heat. All sample were good.

5. Tuftbinds were the same in all products and very acceptable, δlbs.to 10 lbs.

6. Aachen test (for dimensional stability) a. New primary backing Acceptable b. CO8 Acceptable c. SI Acceptable d. Single woven Unacceptable

Attorney Docket No. 10398-29 5

IP E T / ¹ IMiJ? WB$ ^n' iS ^ll * ^>11 *' ""^ ^' Unacceptable 7. Primary Strength:

Tensile Test of (1) warp, (2) fill, (3) bias, which measures the strength of the primary. a. A standard woven polypropylene primary Warp 100 lbs./sq. in.

Fill 70 lbs./sq. in.

Bias 50 lbs./sq. in. b. Improved primary backing (present invention) Warp 108 lbs./sq. in. Fill 167 1bs./sq. in.

Bias 100 lbs./sq. in. c. CO8 woven primary

Warp 121 lbs./sq. in.

Fill 116 lbs./sq. in. Bias 120 lbs./sq. in.

The improved backing material in accordance with the present invention may be practiced in the form of several embodiments. In a preferred embodiment, the improved primary backing material includes the following specifications: 14 / 20 PICK REINFORCED PRODUCT

Weave: Plain or Modified plain

Type of Primary Yarn: Flat PP tape with shrinkage percentage of 0.2 to 1 %

Construction: 22 to 24 end per inch

Elimination yarn Construction: 1 end per inch

Type of 2 ^nd Secondary yarn: Fiberglass yarn coated with vinyl coated and/or uncoated Construction: 1 end per inch across the fabric, 3 to 5 ends per 3 inch every 12 inches across the fabric, 4 to 5 ends per inch on selvedge up to 3 to 4 inches on both sides and thereafter, and 2 to 3 ends per inch up to 4 to 5 inches on each side selvedges to reinforce. Weft:

Type of Primary Yarn: Flat PP tape with shrinkage percentage of 0.2 to 1%

Construction: 6 or 18 ends per inch. Type of 1st Secondary Yarn: Fiberglass yarn coated with Vinyl and/or uncoated

Yarn Color: Charcoal and/or Black

Construction: 1 or 2 end per inch

In an alternative embodiment of the present invention, the improved primary backing of the present invention would include the following specifications:

14 / 18 / 20 PICK REINFORCED PRODUCT

Weave: Plain or Modified plain Warp:

Type of Primary yarn: Flat PP tape with shrinkage percentage of 0.2 to 1 % Construction: 20 to 24 ends per inch.

Type of 1 ^st Secondary yarn: Static Elimination yarn

Construction: 1 end per inch

Type of 2 ^nd Secondary yam: Fiberglass yarn coated with Vinyl coated and/or uncoated.

Attorney Docket No. 10398-29 7

ff> F p;, y gi qμqμ.f l;;;end per inch across the fabric,

3 to 5 ends per 3 inch every 12 inches across the fabric,

4 to 5 ends per inch on selvedge up to 3 to 4 inches on both sides and thereafter, and

2 to 3 ends per inch up to 4 to 5 inches on each side selvedges to reinforce.

Weft or Fill:

Type of Primary Yarn: Multifilament or Spun yam of PP or Polyester or Blend of PP and Polyester with a shrinkage percentage of 0.2 to 1%

Construction: 10 to 22 ends per inch.

Type of Secondary Yarn: Fiberglass yarn coated with Vinyl and/or uncoated

Construction: 1 or 2 end(s) per inch

Property ASTM Range

Weft or Fill Tensile D4632 210 to 250 lbs.

Warp Tensile D4632 175 to 200 lbs.

Warp and Weft or

Fill Shrinkage D3334 Under 1%

Although exemplary embodiments of the present invention have been shown and described, many changes, modifications, and substitutions may be made by one having ordinary skill in the art without necessarily departing from the spirit and scope of the invention.

Attorney Docket No. 10398-29