Abrasion-resistant composite-coated string for sports racquets and fishing equipment

Abstract

A string for various kinds of recreational equipment is a composite-coated monofilament string which includes a single filament or a bundle of multiple filaments of string and a composite coating surrounding and bonded to the single filament or bundle of multiple filaments. The monofilament and multifilament string can be made from any of suitable conventional material. The composite coating in each construction of the string includes a matrix material and particles of PTFE interspersed within the matrix material and within a range of about 11% to 20% by weight of the composite coating. The matrix material can be a suitable synthetic material.

Description

[0001] This utility patent application claims the benefit of provisional application No. 60/187,956 filed Mar. 9, 2000.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention generally relates to strings useful in sports and recreational equipment and, more particularly, is concerned with an abrasion-resistant composite-coated string for sports racquets and fishing equipment.

[0004] 2. Description of the Prior Art

[0005] Strings used in recreational equipment, such as sports racquets and fishing equipment, are generally constructed of natural materials and synthetic materials that are well-known in the art. These strings are sometimes coated with materials intended to protect the structural elements of the string.

[0006] Typical coatings which have been used to protect the structural elements of the string include nylon, polyurethane and polytetrafluoroethylene (PTFE). Nylon and polyurethane are typically applied to the surface of strings by coextrusion of the nylon and polyurethane onto the surface of the string construction to provide an abrasion barrier to protect the construction of the string. PTFE has been used in the past by dipping the string into a liquid solvent or carrier containing dissolved PTFE. After dipping the string, the solvent evaporates leaving a coating of PTFE. For instance, U.S. Pat. No. 4,377,620 to Alexander discloses applying a coating film on the string by drying a liquid formed by dispersing minute particles of ethylene tetrafluoride resin either in a solvent or a molten resin. The ethylene tetrafluroide resin particles have a diameter from 0.1 to 10 microns and, in the mixture with a polyester or polyamide resin, are from 3 to 10% by weight. The thickness of the coating film is typically in the range of 5 to 40 microns (0.005 to 0.040 mm).

[0007] However, the PTFE does not bond well with the surface of the string construction and is quickly removed by rubbing the surface of the coating. While the aforementioned coatings provide some protection, they are worn away relatively quickly due to abrasion caused by strings rubbing against themselves or other objects. Therefore, there is a need to improve the abrasion resistance of the coatings used on strings for sports racquets and fishing equipment.

SUMMARY OF THE INVENTION

[0008] The present invention provides an abrasion-resistant composite-coated string designed to satisfy the aforementioned need. The composite coating is a matrix material interspersed with PTFE of between 11% to 20% by weight. The advantage of the composite coating applied on the string is that its matrix material provides an acceptable bond to the respective surfaces of the single filament or bundle of multiple filaments while the interspersed PTFE reduces the friction resulting from adjacent strings rubbing against each other or other objects and therefore reduces the abrasion and wear on the string.

[0009] Accordingly, the present invention is directed to an abrasion-resistant string for use with various types of recreational equipment. The string includes a single filament or a bundle of multiple filaments of string and a composite coating surrounding and bonded to the single filament or bundle of filaments. The monofilament and multifilament strings can be made from any of conventional material. The composite coating in each construction of the string includes a matrix material and particles of PTFE interspersed within the matrix material. The matrix material can be a suitable synthetic material, such as nylon or polyurethane.

[0010] These and other features and advantages of the present invention will become apparent to those skilled in the art upon a reading of the following detailed description when taken in conjunction with the drawings wherein there is shown and described an illustrative embodiment of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011] In the following detailed description, reference will be made to the attached drawings in which:

[0012] FIG. 1is a cross-sectional view of a prior art monofilament string used in sports racquets and fishing equipment.

[0013] FIG. 2 is a cross-sectional view of a prior art coated monofilament string used in sports racquets and fishing equipment.

[0014] FIG. 3 is a cross-sectional view of a prior art coated multifilament string used in sports racquets and fishing equipment.

[0015] FIG. 4 is a cross-sectional view of an abrasion-resistant composite-coated monofilament string of the present invention.

[0016] FIG. 5 is a cross-sectional view of an abrasion-resistant composite-coated multifilament string of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

[0017] Referring to the drawings and particularly to FIGS. 1 to 3, there are illustrated cross-sections of several different constructions of prior art strings 10, 12,14 which are all useful in various kinds of recreational equipment, mainly, sports racquets and fishing equipment. With respect to the first construction shown in FIG. 1, the prior art string 10 is a non-coated monofilament string which is only a single filament 16 of string. With respect to the second construction shown in FIG. 2, the prior art string 12 is a coated monofilament string which includes a single filament 18 and a coating 20 surrounding the single filament 18. With respect to the third construction shown in FIG. 3, the prior art string 14 is a coated multifilament string which includes a bundle 22 of multiple filaments and a coating 24 surrounding the bundle 22 of multiple filaments. The monofilament and multifilament strings and the coatings can be made from any of the conventional materials mentioned previously above.

[0018] Referring now to FIGS. 4 and 5, there are illustrated cross-sections of strings 26, 28 constituting two different constructions of the present invention which are both useful in the various kinds of recreational equipment, mainly, sports racquets and fishing equipment. With respect to the first construction of the present invention shown in FIG. 4, the string 26 is a composite-coated monofilament string which includes a single filament 30 of string and a composite coating 32 surrounding and bonded to the single filament 30. With respect to the second construction of the present invention shown in FIG. 5, the string 28 is a composite-coated monofilament string which includes a bundle 34 of multiple filaments and the composite coating 32 surrounding and bonded to the bundle 34 of multiple filaments. The monofilament and multifilament strings can be made from any of the conventional materials mentioned previously above.

[0019] The composite coating 32 in each construction of the string 26,28 includes a matrix material 36 and particles 38 of PTFE interspersed within the matrix material 36. The matrix material 36 can be a suitable synthetic material such as nylon or polyurethane. The amount of PTFE partides 38 contained in the matrix material 36 is within the range of from about 11% to 50% by weight and, preferably, about 20% by weight. The diameter of the PTFE particles 38 in the composite coating 32 is about 3 to 30 microns (3E-06 meters to 30E-06 meters) and preferably 10 microns. The composite coating 32 has a range of thickness about 0.030 to 0.050 mm.

[0020] The advantage of this composite coating 32 is that the matrix material 36 provides an acceptable bond to the respective surfaces of the single filament 30 and the bundle 34 of multiple filaments of the two constructions while the interspersed PTFE particles 38 reduce the friction resulting from adjacent strings rubbing against each other or other objects and therefore reduces the abrasion and wear on the string.

[0021] It is thought that the present invention and its advantages will be understood from the foregoing description and it will be apparent that various changes may be made thereto without departing from the spirit and scope of the invention or sacrificing all of its material advantages, the form hereinbefore described being merely preferred or exemplary embodiment thereof.

Claims

1. An abrasion-resistant string useful in a sports racquet and fishing equipment, comprising:

(a) an elongated single filament of string; and

(b) a composite coating surrounding and bonded to said single filament of string, said composite coating including a matrix material and particles of PTFE interspersed within the matrix material and falling in a range of from 11 % to 50% by weight of the composite coating.

2. The string as recited in

claim 1, wherein said matrix material is a synthetic material.

3. The string as recited in

claim 1, wherein said matrix material is nylon.

4. The string as recited in

claim 1, wherein said matrix material is polyurethane.

5. The string as recited in

claim 1, wherein said PTFE particles interspersed in said matrix material is about 20% by weight of the composite coating.

6. The string as recited in

claim 1, wherein a diameter of said PTFE particles in said composite coating is about 3 to 30 microns.

7. The sting as recited in

claim 1, wherein said composite coating has a range of thickness about 0.030 to 0.050 mm.

8. An abrasion-resistant string useful in a sports racquet and fishing equipment, comprising:

(a) an elongated bundle of multiple filaments of string; and

(b) a composite coating surrounding and bonded to said bundle of multiple filaments of string, said composite coating including a matrix material and particles of PTFE interspersed within the matrix material and falling in a range of from 11% to 50% by weight of the composite coating.

9. The string as recited in

claim 8, wherein said matrix material is a synthetic material.

10. The string as recited in

claim 8, wherein said matrix material is nylon.

11. The string as recited in

claim 8, wherein said matrix material is polyurethane.

12. The string as recited in

claim 8, wherein said PTFE particles interspersed in said matrix material is about 20% by weight of the composite coating.

13. The string as recited in

claim 8, wherein a diameter of said PTFE particles in said composite coating is about 3 to 30 microns.

14. The sting as recited in

claim 8, wherein said composite coating has a range of thickness about 0.030 to 0.050 mm.