BACKGROUND ART Paint brushes utilizing conventional synthetic filaments, such as polyamide (including nylon), polyester, and polyurethane filaments are well known in the art. These brushes have excellent durability but they generally exhibit poorer paint pick-up and release than brushes using natural bristles such as hog bristles.

Because of the foregoing, it has become desirable to develop a paint brush incorporating synthetic crinkle filaments having a wavy or crinkle configuration along their longitudinal axis and combining the same with conventional synthetic filaments resulting in a brush that provides improved paint pick-up and release when compared to brushes having only conventional synthetic filaments. As used herein the term"synthetic crinkle filaments" refers to synthetic filaments which are crimped or deformed to impart a wavy configuration with respect to amplitude and frequency along its longitudinal axis. The term"conventional synthetic filaments"refers to synthetic filaments which are substantially linear along their longitudinal axis and are not intentionally crimped or deformed and do not exhibit a wavy or crinkle configuration along their longitudinal axis.

SUMMARY OF THE INVENTION The present invention overcomes the problems associated with using paint brushes having conventional synthetic filaments by providing a paint brush that incorporates a mixture of synthetic crinkle filaments having a wavy or crinkle configuration along their longitudinal axis along with the conventional synthetic filaments. The mixture of synthetic crinkle filaments and conventional synthetic filaments results in a paint brush that has excellent paint"pick-up", paint release, and provides superior surface coverage with an excellent finish.

Accordingly, an object of the present invention is to provide a paint brush which can be readily used with water-based paints.

Another object of the present invention is to provide a paint brush incorporating both synthetic crinkle filaments and conventional synthetic filaments.

Still another object of the present invention is to provide a paint brush incorporating both conventional synthetic filaments and synthetic crinkle filaments and wherein the synthetic crinkle filaments have a wavy configuration along their longitudinal axis.

A further object of the present invention is to provide a paint brush which has excellent paint"pick-up", paint release, and superior coverage capabilities.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a perspective view of the paint brush of the present invention illustrating the utilization of conventional synthetic filaments and synthetic crinkle filaments therein.

Figure 2 is an enlarged cross-sectional view illustrating the conventional synthetic filaments and synthetic crinkle filaments within the paint brush of the present invention.

Figure 3 is a front elevational view of the paint brush of the present invention.

Figure 4 is an enlarged front elevational view of a synthetic crinkle filament utilized in the paint brush of the present invention.

Figure 5 is an enlarged front elevational view of a conventional synthetic filament

utilized in the paint brush of the present invention.

Figure 6 is a cross-sectional view taken across section-indicating lines 6-6 in Figure 4 illustrating the cross-section of a synthetic crinkle filament.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings where the illustrations are for the purpose of describing the preferred embodiment of the present invention and are not intended to limit the invention described herein, Figure 1 is a perspective view of the paint brush 10 of the present invention. The paint brush 10 includes a handle 12 made from either wood or plastic and which may be finished with a protective coating, such as urethane, or remain unfinished.

One end of a mixture of synthetic filaments 14 is received within an insert (not shown) and is retained therein by a standard technique, such as gluing with an epoxy resin, or the like.

The insert with the mixture of synthetic filaments 14 attached thereto is received within the open end 16 of a ferrule 18. The opposite end of the ferrule 18 is received over the periphery of the end of the handle 12 and is attached thereto by nailing, or by some other attachment method.

The mixture of synthetic filaments 14 is comprised of a plurality of conventional synthetic filaments 20 and a plurality of synthetic crinkle filaments 22, as shown in Figure 2. The conventional synthetic filaments 20 can be representatively polyamide, polyester or polyurethane, or the like. Nylon filaments are especially preferred for many applications. The filaments 20 are generally circular in cross-section and may have a tapered tip. For example, the filaments 20 typically have a base diameter of at least about. 005 inches. Representative commercial filaments might have a base diameter of about. 012 inches and a tip diameter of. 008 inches. In addition, the overall length of the filaments 20 can vary, that is, a portion of the plurality of filaments 20 can be a first length, a second portion of the filaments 20 can be slightly shorter in length, and the remaining portion of the filaments 20 can be still slightly shorter in length. Thus, the exposed length of the plurality of filaments captured within ferrule 18 can vary. Furthermore, the relative number of conventional synthetic filaments 20 to synthetic crinkles filaments 22 within the mixture of synthetic filaments 14 can vary. Preferably, the mixture would comprise from about 10% to about

90% by weight of synthetic crinkle filaments with the remainder being conventional synthetic filaments. Preferably the mixture would be substantially free of natural filaments or bristles such as hog bristles.

In one preferred example, the mixture of synthetic filaments 14 can comprise about 20 to 80% by weight conventional synthetic filaments with the remainder being synthetic crinkle filaments 22. Optimally, for many applications, the mixture of synthetic filaments 14 should be comprised of about 30-70% by weight synthetic crinkle filaments.

The synthetic crinkle filaments 22 are preferably extruded from a polyester resin, such as polybutylene terephthlate, according to conventional practice. The synthetic crinkle filaments 22 are generally circular in cross-section and typically have a tapered tip. If the synthetic crinkle filaments are not tapered, they will generally have a diameter of at least about. 005 inches, and preferably will have a diameter between. 005 and. 025 inches. If the synthetic filaments are tapered, they will generally have a base diameter of at least about . 008 inches and preferably will have a base diameter between. 008 and. 025 inches. The tip diameter of a tapered filament will typically be at least about. 005 inches and preferably will have a tip diameter between. 005 and. 015 inches. For example, in one preferred embodiment, the filaments 22 may have a base diameter of. 012 inches and a tip diameter of. 008 inches, each diameter having a tolerance of plus or minus 15%. Alternatively, in another preferred embodiment, the filaments 22 may have a base diameter of. 015 inches and a tip diameter of. 010 inches, each diameter having a tolerance of plus or minus 15%. In addition, each synthetic crinkle filament 22 is crimped along its longitudinal axis utilizing conventional crimping apparatus to impart an average of about 4 to 12 crimps per inch in the longitudinal direction, and preferably about 8 crimps plus or minus 1 crimps per inch in the longitudinal direction, as shown in Figure 4. The amplitude of each crimp in the filament 22 typically average at least about. 010 inches and is especially preferred to average about . 018 inches plus or minus. 003 inches. Although it is generally preferred to utilize synthetic crinkle filaments having crimps which are substantially regular in both frequency and amplitude, it is possible for some applications to utilize filaments whose crimps are random and irregular in both frequency and amplitude. One representative method of preparing synthetic crinkle filaments having irregular crimps is to gather a plurality of monofilament synthetic filaments and pass them between a pair of gear wheels having rounded and

irregular gear teeth. This is contrary to conventional crimping which is accomplished in one representative manner by passing the filaments in a spread-apart manner through regularly spaced crimping gears. Representative commercial synthetic filaments are available from Specialty Filaments, Inc. of Odenton, Maryland. One preferred commercial sample is Ketlar 382248 tapered polyester filaments from Specialty Filaments.

In a standard test utilized by manufacturers of paint and/or paint brushes, paint brushes containing a plurality of conventional synthetic filaments 20 and a plurality of synthetic crinkle filaments 22 was tested. These examples are set forth below. In these tests, for paint pick-up and release, the brush is dipped repeatedly into the paint, weighed to determine paint pick-up, then applied to a substrate for a given distance and a given number of strokes. The amount of paint released is determined by the weight of paint lost from the brush by this application. Greater paint pick-up and greater paint release are preferred.

Stiffness is tested by measuring 1/2 ouf the exposed length of filament and deflecting it over a scale at 30° angle to measure pressure in grams.

EXAMPLE 1 A 3 inch wide flag brush (with ends of the filaments being split) containing 45% by weight synthetic crinkle polyester filament (Ketlar tapered polyester filament 382248 from Specialty Filaments) and 55% by weight conventional nylon filament was prepared. The brush thickness was 7/8 inch and the overall trim length of the filaments was 3 7/16 inch. After repeated dips of the brush in PROMAR 200 Latex paint (commercially available from The Sherwin-Williams Company), the average "pick-up"per dip was 64.8 grams and the average paint release was 9.2 grams. In coverage tests the average coverage for this brush was 220 square inches. The average stiffness was 496 grams.

This brush was compared to an identically prepared brush using 55% by weight of the same nylon filaments but replacing the synthetic crinkle polyester filament with an equal weight of conventional (non-crimped) polyester filament.

This conventional brush showed an average paint"pick-up"per dip of 50.6 grams and the average paint release was 8.0 grams. The average coverage was 209 square inches and the average stiffness was 674.

EXAMPLE 2 A 21/2 inches wide tapered brush containing 45% by weight synthetic crinkle polyester filament (Ketlar tapered polyester filament 382248 from Specialty Filaments) and 55% by weight conventional nylon filament was prepared. The brush thickness was 5/8 inch and the overall trim length of filaments was 2 7/8 inches.

After repeated dips of the brush in a commercial sample of PROMAR 200 latex paint, the average paint"pick-up"per dip was 26.4 grams and the average paint release was 5.0 grams. The average stiffness of the brush was 551.

This brush was compared to an identically prepared brush using 55% by weight of the same nylon filaments but replacing the synthetic crinkle polyester filament with an equal weight of conventional (non-crimped) polyester filament.

This conventional brush showed an average paint"pick-up"per dip of 21.8 grams and the average paint release was 4.2 grams. The average stiffness was 525.

Certain modifications and improvements will occur to those skilled in the art upon reading the foregoing. It should be understood that all such modifications and improvements have not been expressly set forth herein for the sake of conciseness and readability, but are properly within the scope of the following claims.