US3609792A - Plastic set corn brooms and the like - Google Patents

Abstract

The invention provides a brush or corn broom formed of fibers set in a plastic formulation which is set condition is stratified, the upper portion or stratum being substantially rigid and the lower portion or stratum from which the broom corn or other fibers project being substantially flexible. The plastic formation consists of: 50 to 100 parts of a casting type of polyester resin; 10 to 20 parts of styrene monomer; 6 to 15 parts of a lightweight aggregate such as fine perlite, micro-balloons or vermiculite, and fillers such as pecan shell flour or corn meal; and 1/2% to 1 1/2% of a curing agent. A preformed hollow styrene or other type broom or brush cap in inverted position is used as the mold to form the finished brush or broom fibers being inserted into such cap and liquid. The gelation of the admixture is delayed for about five minutes and the gelation occurs within five minutes thereafter; so that the broom or brush can be handled thereafter without separation of the fibers and plastic. Instead of a cap, an open reusable mold may be employed to form the plastic set fibrous brush construction having two strata.

Description

06L 1971 A. H. WIESE PLASTIC SET CORN BROOMS AND THE LIKE 2 Sheets-Sheet 1 Filed April 28, 1970 Fig.

INVENTOR. 17L 5 E1? 7' fi M555 Oct. 5, 1971 A. H. WIESE 3609792 PLASTIC SET CORN BROOMS AND THE LIKE Filed April 28, 1970 2 Sheets-Sheet 2 IIIIIIIIIIYIIIIII' P I I N VENTOR. 445527 64 M555 \giw, 1

United States Patent 3,609,792 PLASTIC SET CORN BROOMS AND THE LIKE Albert H. Wiese, Chesterfield, M0., assignor to National Industries for the Blind, New York, N.Y. Filed Apr. 28, 1970, Ser. No. 32,617 Int. Cl. A46b 3/02 U.S. Cl. 193 11 Claims ABSTRACT OF THE DISCLOSURE The invention provides a brush or corn broom formed of fibers set in a plastic formulation which in set condition is stratified, the upper portion or stratum being substantially rigid and the lower portion or stratum from which the broom corn or other fibers project being substantially flexible.

The plastic formation consists of:

50 to 100 parts of a casting type of polyester resin;

10 to parts of styrene monomer;

6 to 15 parts of a lightweight aggregate such as fine perlite, micro-balloons or vermiculite, and fillers such as pecan shell flour or corn meal; and

/2 to 1 /2 of a curing agent.

A preformed hollow styrene or other type broom or brush cap in inverted position is used as the mold to form the finished brush or broom, the plastic formulation in liquid form being poured into the inverted cap, and brush or broom fibers being inserted into such cap and liquid. The gelation of the admixture is delayed for about five minutes and the gelation occurs within five minutes thereafter; so that the broom or brush can be handled thereafter without separation of the fibers and plastic. Instead of a cap, an open reusable mold may be employed to form the plastic set fibrous brush construction having two strata.

The present invention relates to plastic set brooms and brushes utilizing broom corn, plastic filaments and other fibers commonly used for brooms and brushes. For convenience the present invention will be described with reference to broom corn. It will be understood, however, that the expression broom corn is intended to cover in addition to broom corn such other filaments and fibers as are commonly used in the production of brooms and brushes.

More particularly, the present invention provides a much improved plastic formulation for setting in situ broom corn, plastic filaments and other fibers, wherein said plastic is stratified to provide an upper portion or stratum which is substantially rigid and a lower portion or stratum which is substantially flexible.

In the preferred form of the invention a cap or shroud which forms part of the finished broom or brush is in verted and serves as the mold for the plastic formulation and the broom or brush fibers inserted therein. It will be understood however that a reusable mold nTay be employed with the plastic formulation of the present invention to provide plastic set broom and brush constructions without an enveloping cap or shroud serving as the mold. In the inverted position of the cap the flexible stratum is formed at the top and the rigid stratum is formed at the bottom of the cap (or mold).

For convenience, however, the invention will also be described with reference to a corn broom wherein the cap or shroud constitutes part of the finished broom and also serves as the mold for the plastic formulation into which the broom corn or the fibers or other filaments are inserted and suitably retained upon setting of such plastic. It will also be described with reference to such a corn 'ice broom which also retains in position a broom handle inserted into such cap or shroud.

Among the problems which have heretofore confronted the industry in the production of brooms of broom corn are: (a) that the outer cap or shroud which envelops the upper portion of the finished broom and which is frequently made of plastic should not be damaged by the excessive heats of hot-melt adhesives, nor lose its flexibility by such heats; (b) that the broom corn should not be damaged by being exposed to excessive heats and hot melts; (c) that the hot-melts used on setting should not lose their flexibility so as to be unyielding during normal use of the broom; (d) that cold-setting plasticlike material should not take so long to set as to render their use uneconomical; and (e) that such cold-setting plastic-like materials when set should not be so rigid as to be inflexible at the point of join with the effective broom corn sweeping segments.

I have found that all of the foregoing problems of the prior art are overcome by my invention of a plastic formulation for setting and retaining broom corn in a preformed plastic or like cap or shroud and that such plastic formulation due to the heat of reaction has all of the advantages of a hot-melt and none of the disadvantages. Also, I have found that with my plastic formulation I obtain a stratification whereby at the upper end of the broom adjacent the handle a substantially rigid section is formed whereas at the lower end of the cap or shroud a resilient section is formed. I have found that such stratification occurs with the plastic formulation which I use without special steps being required to assure that such stratification takes place.

More particularly I have found the preferred plastic formulation to be:

50 to 100 parts of a casting type of polyester resin; 1020 parts of styrene monomer;

615 parts of a lightweight aggregate and fillers; and /2 to 1 /2 of a curing agent.

A preformed hollow styrene or other type broom cap or shroud is inverted and used in such inverted position as a mold. The inverted cap is partially filled (to about onehalf its depth) with such plastic formulation, which is in a liquid state, and a quantity of broom corn is inserted in the cap and plastic formulation. The assembly is then permitted to set in air.

The corn broom thus produced has two distinct strata, the one near the handle being rigid and the one nearer the skirt portion of the cap or shroud being flexible.

Referring to the various elements which go into the plastic formulation, and having in mind also the economics of broom manufacture:

I have found that flexible polyester casting resins such as the types which are now used for simulating wood in furniture and allied trades, work very well in my typical formulation.

The styrene monomer is primarily used for the purpose of increasing the fluidity of the resin so that the plastic compound will readily flow around each individual broom or other fiber element. It also permits a separation of the lightweight aggregate and the filler during the curing process so as to create a variation in density or the stratification earlier mentioned. The styrene monomer also reduces the cost of the over-all plastic compound. As the styrene monomer is however, a degrading additive, I have found that I can reduce the amount of styrene monomer if the resin, aggregate and filler mixture, including the monomer, is warmed to about F. to F. before adding a curing agent. Such warming can be done by utilizing a barrel heater for the dispensing container. Such preheating or warming reduces the amount of curing agent required (which is a saving in cost) and the amount of monomer required (which reduces degradation).

The lightweight aggregate and the filler reduce the thermal conductivity of the plastic compound so that the heat generated will not distort the plastic cap or shroud. They also reduce the heat of reaction so that broom corn or other broom and brush fibers are not degraded at the interface with such plastic from which they protrude. I have found that the temperature of reaction must be carefully controlled so as to be as low as 13 F. at the interface provided by the setting resin and the protruding fibers; whereas I have found that an inside temperature within the setting resin may be as much as 300 F.

The lightweight aggregate and filler are used to adjust the thermal conductivity of the plastic compound. This adjustment is very important as it avoids the necessity for long curing.

The lightweight aggregate preferably is finely ground perlite, micro-balloons, vermiculite, or other lightweight aggregate which readily floats.

The heavier filler such as pecan sheel flour, corn meal, and other non-oil-absorbent fillers, settles to the bottom prior to gelation of the plastic to form a heavier layer or stratum. Pecan shell flour may be used in quantities of to 30%. It is essential when the thermoplastic shroud can be adversely affected by the heat of reaction. It is a heat absorbing material which also prevents degradation of the broom corn or other fibers. Some of the fillers also improve the physical qualities of the plastic, such for instance as where it is desired to provide a molded plastic with molded screwthreads.

The fourth preferred element in the plastic formulation is a small amount of a curing agent selected in accordance with the recommendations of the manufacturer of the polyester casting resin.

In addition to the foregoing, the present invention contemplates that the degree of separation of the aggregate filler can be controlled by the addition of a thixotropic agent. One such agent is fused silica.

Inhibitors and promoters may also be added to the resin to control the speed of reaction so that the styrene shroud or cap which also serves as a mold will not fail by dissolving or melting because of heat. The promoters I prefer are:

Percent (a) Cobalt napthanate, 6% to 12% solution 0.7-.25 (b) Di-methyl aniline .1.25

The cobalt napthanate serves to promote the speed of gelation after the curing agent or hardener is added. The di-methyl aniline serves to speed up the final curing process after gelation, which also is a factor which determines how much heat of reaction is generated in a period of time. The time of hardening is an important factor in an in-line process.

Referring to the drawings wherein the preferred form of the invention is illustrated:

FIG. 1 is a front elevational view of a corn broom made in accordance with and embodying the present invention.

FIG. 2 is a side elevational view of the corn broom of FIG. 1.

FIG. 3 is a sectional view taken along the line 33 of FIG. 1 and looking in the direction of the arrows.

FIG. 4 is a fragmentary sectional view taken along the line 44 of FIG. 2 looking in the direction of the arrows.

FIG. 5 is an inverted sectional view of the shroud or cap for the corn broom with the handle in place showing the liquid plastic formulation provided by the present invention prior to insertion of the broom corn; and

:FIG. 6 is a view similar to FIG. 5 showing the broom corn in course of insertion into the shroud or cap and liquid plastic formulation.

For a better understanding of the invention reference will first be made to FIGS. 5 and 6 wherein a corn broom shroud or cap 10, preferably of impact styrene, or a slowly reactive plastic or resin absorbent material, has a. handle 4 receiving flanged aperture 11 for receiving a broom handle 12 which is inserted therein. The cap 10 is shown in its inverted position which is the position it assumes during the preparation of the broom according to the present invention. The handle 12 serves as a plug for the aperture 11.

The cap 10 is shown as being partially filled with a plastic formulation 13 which occupies approximately onehalf of the cap before insertion of the broom corn. Such plastic formulation is in the liquid stage.

Referring now to FIG. 6, broom corn 16 of a suitable quantity and length is inserted into the inverted cap 10 and is forced downwardly into the liquid plastic 13 until the inner ends 17 of the broom corn fully engage the inner face 18 of the cap 10 and surround the portion of handle 12 disposed within the cap 10. In such position the plastic 13 is permitted to set.

The finished corn broom after setting in the plastic formulation is illustrated in FIGS. 1 to 4 inclusive, FIG. 1 showing it in front elevation and FIG. 2 showing it in side elevation. The interior structure of the corn broom after setting of the plastic is illustrated in FIGS. 3 and 4, FIG. 3 being a sectional view taken along the line 3-3 of FIG. 1 and FIG. 4 being a fragmentary sectional view taken along the line 4-4 of FIG. 2.

As before mentioned the cap 10 is preferably of impact styrene and has a broom handle 12 inserted through an aperture 11 at the top portion of cap 10. As shown in the drawing the broom handle 12 preferably has a reduced cylindrical portion 19 which thereby provides a shoulder 20 for engagement with the outer surface of the flanged aperture 11. The broom handle has an inwardly tapered or conical portion 21 having a through-hole 22.

During the setting stage it is preferred that gelation be held off for about five minutes so that the liquid plastic may run through the broom corn and completely encompass the individual fibers. A gelation time of more than five minutes would be uneconomical on a production basis.

After gelation sulficient curing in the next five minutes is assured so that the broom in its set condition can be handled with conveyors and other manufacturing equipment without disturbing the plastic and fibers.

With these time limitations it has been found that with a high concentration of fillers such as pecan shell flour of 50% to 25%, such fillers will have settled prior to gelation.

As best seen in FIG. 4, the set plastic formulation 13 is composed of two strata, an upper stratum 23 and a lower stratum 24. These strata are formed as heretofore outlined. The upper stratum 23 has been found to contain a high percentage of about 50% to 75% of the polyester casting resin, which imparts to such upper surface considerable strength for withstanding abuse. The lower stratum 24 has been found to contain a relatively small amount of the polyester casting resin (approximately 10%) and a high percentage of the lightweight aggregate. Such lower stratum is much softer and more elastic than the upper stratum and provides flexibility for the sweeping segments of the broom corn. The lower percentage of casting polyester resin has also served to lower the reactive temperature at the interface of the resin and protruding broom corn or other fibers.

It has also been found that the density of the upper stratum 23 is approximately 78 pounds per cubic foot, while the density of the lower stratum where the broom corn elements 16 protrude from such stratum is only about 38 pounds per cubic foot.

It will also be noted that the through-hole 22 in the handle 12 during the plastic and broom corn setting operation is filled with set plastic 25 which serves to maintain the handle and set plastic in assembled relation.

Also, the preferred plastic formulation which utilizes a styrene monomer will slowly dissolve or absorb a portion of the inner surface of the shroud or cap and will serve as an adhesive to bond the shroud to the plastic.

A staple also may be inserted through the cap and engaged in the reduced portion 19 of the handle 12.

As earlier mentioned, pecan shell flour can be used in the formulation, preferably in quantities of between 5% to 40%. Such pecan shell flour not only reduces the cost of the plastic formulation, but it has been found to produce a plastic material which will withstand stapling and nailing. Thus, the staple 26 can penetrate the styrene cap, the resin formulation and the wooden handle without giving rise to any cracks or breaks in the same.

As a general rule it has been found that approximately 10 grams of plastic formulation or compound will set approximately 1 ounce of broom corn. For whisk brooms, between 10 to 30 grams of plastic formulation or compound is used. In upright brooms, between 60 to 100 grams is required, depending upon the size of the brooms being made.

A broom constructed according to the present invention having a properly designed plastic cap can be made with as much as 50% less broom corn than with the conventional methods used for manufacturing brooms. Moreover, it does not require the expensive sewing operation which is conventional with most brooms.

In the practice of the process of the present invention it has been found that the aggregate and filler are essential for controlling the heat of reaction or polymerization. The outside surface temperature is controlled to stay within 130 F. to 200 F. The join (or interface) of the fibers with the lower stratum is controlled to 120 F to 150 F. The internal heat within the upper stratum may build up to as much as 300 F.

While the present invention has been illustrated and described in its preferred forms, it will be understood that variations may be made therein without departing from the scope of the appended claims.

What I claim is:

1. An article of manufacture comprising a bundle of brush fibers set in a molded plastic retaining member with said brush fibers projecting therefrom, said plastic retaining member having an upper stratum and a lower stratum, the upper stratum being substantially rigid and the lower stratum being substantially flexible, said brush fibers rigidly retained in said upper stratum and flexibly retained in and projecting from the face of said lower stratum.

2. An article of manufacture according to claim 1, wherein the set plastic comprises a mixture of a flexible polyester casting resin, a styrene monomer, a lightweight aggregate and a filler.

3. An article of manufacture according to claim 1, wherein the set plastic comprises a mixture of a flexible polyester casting resin, a styrene monomer, a lightweight aggregate and a filler, said lightweight aggregate selected from the group consisting of perlite, micro-ballons and vermiculite.

4. An article of manufacture according to claim 1, wherein the set plastic comprises a mixture of a flexible polyester casting resin, a styrene monomer, a lightweight aggregate, and a filler, said filler selected from the group consisting of pecan shell flour, corn meal, and other nonoil-absorbent fillers.

5. An article of manufacture according to claim 1, wherein said molded plastic member comprises approximately:

50-100 parts of a flexible polyester casting resin,

10-20 parts of a styrene monomer, and

6-15 parts of a lightweight aggregate and filler.

6. A brush comprising a cap enclosing and retaining a bundle of brush fibers therein, said cap being closed at its upper end and being open at its lower end with the brush fibers projecting therefrom, and a set plastic within said cap retaining said fibers within said cap, said set plastic comprising an upper portion and a lower portion, the upper portion being substantially rigid and the lower portion being substantially flexible, whereby the brush fibers are rigidly retained within the upper end of the cap and the brush fibers are flexibly retained within the lower end of the cap.

7. A brush according to claim 6 wherein the set plastic comprises a mixture of a flexible polyester casting resin, a styrene monomer, a lightweight aggregate and a filler, wherein the density of the set resin at the upper end of the cap is approximately 78 pounds per cubic foot and the density of the set resin at the lower end of the cap is approximately 38 pounds per cubic foot.

8. A brush according to claim 6 wherein the set plastic comprises a mixture of a flexible polyester casting resin, a styrene monomer, a lightweight aggregate, a filler, and fused silica.

9. A brush according to claim 6 wherein the set plastic comprises a mixture of a flexible polyester casting resin, a styrene monomer, a lightweight aggregate, and a filler, and wherein said set plastic is stratified into upper and lower strata, the upper stratum comprising approximately polyester casting resin and the lower stratum comprising approximately 10% polyester casting resin.

10. A brush according to claim 6 wherein said cap at its upper closed end has a handle receiving portion, the handle projecting through such handle receiving portion into said cap, the portion of said handle within said cap having a through-hole therein and said set plastic disposed within said through-hole in the handle to retain said handle and cap in assembled relation.

11. A brush according to claim 6 wherein said cap is formed of impact styrene and the set plastic comprises a mixture of a flexible polyester casting resin, a styrene monomer, a lightweight aggregate, and a filler, said impact styrene cap and said set plastic being adhesively connected.

References Cited UNITED STATES PATENTS 1,202,244 10/1916 Timmis 300-21 2,258,361 10/1941 Hewes 300-21X 2,840,841 7/1958 Maxwell 15193 2,934,777 5/1960 Hanset 15-193X 3,130,434 4/1964 Daw 15192 3,231,920 2/1966 Malpas 15193 PETER FELDMAN, Primary Examiner US. Cl. X.R. 30021

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