Dental floss

Details Dental floss Dental floss

2000-08-15

2001-09-18

Lucchesi, Nicholas D. (Department: 3732)

Toilet

Toothpick

Reexamination Certificate

active

06289904

ABSTRACT:

FIELD OF THE INVENTION
This invention relates to a dental floss that can be readily gripped and which can be readily inserted into close interdental spaces. More particularly, this invention relates to a tape type of dental floss that has a coating that increases the lubricity of the base fiber to make it easier to use.
BACKGROUND OF THE INVENTION
A well-recognized problem with regard to flosses, whether they are tape flosses or multifilament flosses, is the catching on tooth surfaces during movement into and through close contact interdental spaces. In some instances the floss will break and shred and parts of the floss will become stuck between the teeth. It then takes more flossing to remove floss segments from between one's teeth. This has been a continuing problem which is solved through the use of the new polytetrafluoroethylene (PTFE) fiber flosses. However, PTFE is a relatively expensive fiber. Therefore, it has been an objective to provide a fiber that has the ease of use characteristics of PTFE while using a lower cost fiber. This can be the result of forming a particular fiber composition or it can be by providing a coating on a non-PTFE fiber that makes the non-PTFE fiber mimic a PTFE fiber in use as a floss. Since a PTFE fiber has a low coefficient of friction (COF), it inherently readily passes into close interdental spaces.
PTFE flosses are disclosed in U.S. Pat. Nos. 5,033,488 and 5,209,251. These consist of one or more strands of expanded PTFE with a wax or other coating to increase the grippability of the fiber in use as a floss. A microcrystalline wax was found to be one effective wax. However, other coatings that adhere to PTFE, that are not brittle at about room temperature and which have a melting point above 50° C. can be used. The coating will raise the COF of the expanded PTFE above about 0.08. A wax coated non-PTFE fiber floss is disclosed in U.S. Pat. No. 4,996,056. In this patent there is disclosed a nylon, polyester or polypropylene fiber that is coated with solid particles of a fluoropolymer in a binder. The binder can be a wax or a non-wax, with a wax being preferred. The fluoropolymer particles can be PTFE particles of a particle size of about 1 to 50 millimicrons. European Patent Application 423 541 A2 discloses formulations for coating flavorants and other materials onto PTFE surfaces, including flosses.
These patent publications set out the present state of the art of flosses that contain PTFE. The expanded PTFE fiber flosses slip easily into tight interdental spaces. However, expanded PTFE film can cost 3 to 10 times the cost of other fibers. Although a useful floss fiber, it is expensive. The non-PTFE fiber coated with particulate PTFE is not a low COF floss. This is the case since the PTFE particle coating is scrapped from the fiber during insertion between the teeth and the subsequent motion of the floss. The full benefits of a PTFE fiber then are no longer achieved.
Waxes have been coated onto conventional floss fibers for many years. Although microcrystalne waxes are the most commonly used waxes, other waxes, such as beeswax, paraffin waxes, carnauba wax and polyethylene wax can also be used. The floss fibers are usually nylon, however, other fibers such as polyethylene, polypropylene, polyester, cellulose and cotton also are used. The wax coating lubricates the fiber so that it can more easily slip into tight interdental spaces and also serves as a binder for multifilament flosses. However, none of these coatings onto these floss fibers have proven to impart to the non-PTFE fibers the characteristics of PTFE flosses. The objective is to use a lower cost conventional fiber and to achieve the surface lubricity of PTFE.
BRIEF SUMMARY OF THE INVENTION
It has been found that non-PTFE fibers such as nylons, polyenes such as polyethylene, polypropylene and polybutadiene, polyesters, ethylene-propylene copolymers, ethylene-vinyl acetate copolymers, ethylene vinyl alcohol copolymers, and cellulosics can be coated so that they can gain at least some of the surface characteristics similar to those of PTFE. The usual PTFE flosses are in the form of a tape. They usually are of about 800 to 1500 denier prior to any coating. A non-PTFE fiber strand can be made to mimic many of the surface characteristics of PTFE by the application of a two-stage coating. The non-PTFE fiber strand is first coated with a nylon bonding coating and then with a wax coating. The nylon bonding coat is in the nature of a primer coat. The wax coat is the coating which is to duplicate as much as possible the desirable properties of PTFE. The overall coating level of the two coatings onto the fiber strand is about 12% to 22% by weight. The ratio of the wax coating to the nylon bonding coating is about 1:1 to about 3:1.
The two-stage coating process produces a non-PTFE fiber strand that has the lubricious surface characteristics of PTFE. The strand slips readily between teeth, including teeth with tight interdental spaces. The coated strand also is easy to grip for flossing. The fiber strand does not slip from between a person's fingers when the strand gets caught between two closely spaced teeth.
DETAILED DESCRIPTION OF THE INVENTION
It has been found that a non-PTFE fiber strand can be produced that has surface characteristics similar to many of those of PTFE. That is, it has a lubricious surface that mimics the surface of PTFE in use as a floss. A preferred film strand is nylon and the invention will be described with regard to nylon but with the understanding that other films will be used.
The nylon fiber strand can be a monofilament strand or a multifilament strand. It will have a denier of about 300 to 2000 denier. The nylon bonding coat is comprised of a polyamide solution, a silicone, PTFE resin powder and an alcohol as the solubilizing and application vehicle. The formulation contains about 10% to about 20% of the polyamide solution, and preferably about 15% by weight. The silicone is present in an amount of about 0.5% to about 3% by weight, and preferably about 1.5%. The PTFE resin powder is present in an amount of about 0.2% to about 1% by weight, and preferably about 0.5%. The remainder is alcohol carrier and solubilizing vehicle which alcohol usually is ethanol.
The wax coat is comprised of waxes, along with glycerol esters and silicones. Preferably the waxes are comprised of a mixture of a low melting point wax and a high melting point wax. A low melting point wax is a wax that has a melting point between about 50° C. and 65° C. A high melting point wax is a wax that has a melting point above about 75° C. The coating also includes a glycerol ester, such as glycerol triacetate, and a silicone.
The silicone preferably is a silicone copolymer. The silicone provides the formulation which creates a silky, slippery surface effect on the fiber surface. Suitable silicone copolymers are organosilicones.
The waxes comprise about 80% to about 96% by weight of the formulation. The low melting point wax is present in a ratio of about 1:1 to about 2:1 of the high melting point wax. The glycerol ester is present in an amount of about 5% to about 10% by weight with the silicone being present in an amount of 1% to 3% by weight. The preferred glycerol ester is glycerol triacetate. The preferred silicone is a silicone copolymer such as methylalkyl polysiloxane copolymer.
The nylon bond coating is put into the nylon in a first step. This can be put onto the nylon strand using essentially any coating technique. These include lick roll, submersion and squeeze rolls and spraying. After coating, the fiber strand is heated to remove the ethanol. The fiber strand then is coated with the wax coat. This wax coat can be put onto the fiber by any of the above mentioned techniques.
The overall coating level on the fiber strand is about 12% to about 22% by weight. The ratio of the wax coating to the nylon bond coating is about 1:1 to about 3:1.


REFERENCES:
patent: 4996056 (1991-02-01), Blass
patent: 5033488 (1991-07-01), Curtis et al.
patent: 5209251 (1993-05-01), Curtis et al.
paten

Affiliated with

Also associated with

Rating

Dental floss does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Dental floss, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Dental floss will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2464586