Patent Application
20080050519
The term latex is known by those skilled in the art to mean an aqueous emulsion of natural or synthetic rubber or plastic (synthetic polymer) globules. That is, water forms the continuous phase of the emulsion and natural or synthetic rubber or film-forming polymers form the discontinuous phase.
The term decomposition as applied to hydrogen peroxide and as used herein means that the hydrogen peroxide undergoes the chemical reaction shown below:
2H2O2 (aq)→2H2O (l)+O2 (g)
The term “activating agent” as used herein means any substance that causes hydrogen peroxide to undergo the chemical reaction shown above and described as decomposition.
The present invention provides improved bundle encapsulation/penetration, stitch/fiber lock, wet tuft bind, lamination strength, and/or dimensional stability when applied to textiles, such as tufted carpet, including scatter rugs as well as broadloom carpet.
The formulation of the present invention that can be used to make the foam of the present invention comprises a mixture of an aqueous emulsion of a natural or synthetic film-forming polymer, hydrogen peroxide and an activating agent for the decomposition of the hydrogen peroxide. The formulation includes a sufficient amount of hydrogen peroxide such that when the hydrogen peroxide decomposes it releases enough oxygen gas to convert the formulation to a foam. The formulation includes a sufficient amount of activating agent such that it causes the hydrogen peroxide to decompose at a desired rate and produces a desired amount of oxygen gas to convert the formulation to a foam.
A typical formulation in accordance with the present invention is shown in Table 1 below.
Aqueous emulsions or solutions of film-forming natural or synthetic polymers (both homopolymers and copolymers) useful in the present invention include, but are not limited to, styrene-butadiene latex, carboxylated styrene-butadiene latex, ethylene vinyl acetate latex, polyvinyl acetate latex, polyvinyl chloride latex, chloroprene latex, neoprene latex, silicone rubber dispersion, natural rubber latex, polyvinyl alcohol solution, polyvinyl alcohol solution stabilized with bromine, acrylic latex, styrene acrylic latex, vinyl acrylic latex, and compatible mixtures thereof. The amount of the aqueous emulsion of film-forming natural or synthetic polymers used in the formulation of the present invention depends on the type of application for which the foam will be used. Preferably, the amount of an aqueous emulsion of film-forming natural or synthetic polymers useful in the present invention is about 60% to about 99% by weight of the formulation; especially, about 15% to about 50% by weight of the formulation.
Prior art latex formulations typically have been a blend of natural and synthetic rubber latex, such as 60% to 90% by weight natural rubber latex and 10% to 40% by weight synthetic rubber latex. It is specifically contemplated as a feature of the present invention that the formulation of the present invention can be made from 100% synthetic rubber latex, such as 100% styrene-butadiene latex.
The amount of hydrogen peroxide used in the formulation of the present invention depends on the type of application for which the foam will be used. Preferably, the amount of hydrogen peroxide useful in the present invention is about 0.5% to about 40% by weight of the formulation; especially about 1% to about 10% by weight of the formulation.
Activating agents useful in the present invention are any material that catalyzes the decomposition of hydrogen peroxide. Activating agents useful in the present invention include, but are not limited to, enzymes and oxidizing/reducing agents. The amount of activating agent used in the formulation of the present invention depends on the type of application for which the foam will be used. Preferably, the amount of activating agent useful in the present invention is about 0.05% to about 5% by weight of the formulation; especially, about 0.1% to about 1% by weight of the formulation.
Any enzyme that catalyzes the decomposition of hydrogen peroxide can be used. Enzymes useful in the present invention include, but are not limited to, catalase, chymotrypsin, lipase, rennet, trypsin, actinidin, α-amylase, β-amylase, bromelain, β-glucanase, ficin, lipoxygenase, papain, asparaginase, glucose isomerase, penicillin amidase, protease, pullulanase, aminoacylase, glucoamylase, cellulase, dextranase, glucose oxidase, lactase, pectinase, pectin lyase, protease, raffinase, invertase, and mixtures thereof.
Any oxidizing/reducing agent that catalyzes the decomposition of hydrogen peroxide can be used. Oxidizing/reducing agents useful in the present invention include, but are not limited to, CuCl2, CuO, ZnO, MnO2, KI, and Fe(II) and Fe(III) oxides. Iron oxide-bearing clays, such as montmorillonite K10, can also be used as a source of an activating agent.
The formulation of the present invention can also include various additives to improve or adjust the properties of the foam as desired. Such additives can include, but are not limited to, fillers, thickening agents, gelling agents, vulcanizing agents, accelerators, antimicrobial agents, and other additives typically included in prior art latex foam formulations.
Typical gelling agents used for latex formulations can be used in the formulation of the present invention. Such gelling agents include, but are not limited to, sulfur-containing compounds, chlorides, acetates; fluorides; and zinc salts know as gelling agents. The amount of gelling agent used in the formulation of the present invention is an amount sufficient to cause the formulation to gel within a desired time. Such amounts include, but are not limited to, about 0.2% by weight to about 6% by weight of the formulation. A time-based gelling agent, such as sodium silica fluoride, is preferred. A particularly preferred formulation includes about 10 weight parts of an aqueous emulsion of a film forming polymer, about 4 weight parts hydrogen peroxide, about 1 weight part gelling agent and about 0.1 weight parts activating agent.
Typical ingredients used as fillers in the composition of the present invention include, but are not limited to, aluminum trioxide, such as P-130A available from Custom Grinders Sales, Inc., Chatsworth, Ga.; aluminum silicate, such as LU-400 available from Lawson-United Feldspar & Mineral Co./K-T Feldspar, Spruce Pine, N.C.; calcium carbonate, such as 200-W available from Georgia Marble Company, Dalton, Ga.; magnesium hydroxide, such as MagneClear 58 available from Martin Marietta Magnesia Specialties, Inc., Baltimore, Md.; fiberglass available from JPS, S.C.; Portland cement; barites; fly ash; ground glass (i.e., glass cullet), rubber crumb, and other inorganic materials. Filler amounts used in the formulation of the present invention are preferably about 0% to about 70% by weight of the formulation; especially, about 45% to about 55% by weight of the formulation. Flame retardant fillers or flame retardant additives, such as magnesium hydroxide or aluminum trihydrate, can also be added to the formulation. Such flame retardant fillers or flame retardant additives can be added in amounts of approximately 0% to 70% by weight of the formulation.
Antimicrobial additives can be added to help control mold and mildew growth in wet environments. Such antimicrobial additives can be added in amounts of approximately 0% to 10% by weight of the formulation. Also, scents or odor eliminators can be added to the formulation. Such scents or odor eliminators can be added in amounts of approximately 0% to 15% by weight of the formulation.
Depending on the desired physical properties of the finished foam or foam-coated textile, other materials can be incorporated into the formulation to achieve the desired effect, while maintaining the performance of the foam.
It is specifically contemplated as a feature of the present invention that the formulation of the present invention can have a solids content of greater than 75% by weight. It is specifically contemplated that the formulation of the present invention can have a solids content of up to about 87% by weight. The higher solids content of the formulation of the present invention permits the use of less water in the formulation which, in turn, permits more rapid drying of the formulation and/or the use of less heat energy to dry the formulation.
Another feature of the formulation of the present invention is that it requires less surfactant than prior art latex formulations. Since surfactants are relatively expensive ingredient, this feature provides a significant cost savings.
Table 2 below shows preferred ranges of the ingredients of a disclosed embodiment of the formulation of the present invention.
It has been further discovered that the inclusion of starch, stearic acid or combinations thereof, improves the retention of gas bubbles within the formulation of the present invention, thereby making the foam more stable. Starches useful in the present invention include, but are not limited to, starch from fruits, seeds, rhizomes or tubers of plants. Preferred starches are corn starch, potato starch, rice starch and wheat starch. Salts of stearic acid include, but are not limited to, salts of alkali metals and salts of alkaline earth metals, such as potassium stearate, sodium stearate, zinc stearate and magnesium stearate. The amount of starch, stearic acid or salts of stearic acid included in the formulation is an amount sufficient to improve the gas bubble retention within the foam; preferably about 0.20% to about 3% by weight of the formulation; especially, about 0.22% to about 1% by weight of the formulation.
Another feature of the present invention is the ability to very precisely control the amount of blowing of the foam. By controlling the amounts of the hydrogen peroxide and the activating agent in the formulation and the ratio of the activating agent to the hydrogen peroxide, the amount of blowing, and, therefore, the amount of foam generation, can be precisely determined, controlled and reproduced.
With reference to the drawing in which like numbers indicate like elements throughout the several views, it will be seen that there is disclosed a floor covering product, such as a carpet 10 (
Collectively, the face pile 14, the primary carpet backing 12 and the loop backs 16 form a facing layer 18. While the facing layer 18 of the carpet 10 has been illustrated in
With further reference to
With reference to
Contained in the storage tank 108 is the latex rubber formulation. Separately contained in the tank 109 is the hydrogen peroxide. Separately contained in the storage tank 110 is the activating agent formulation.
The storage tanks 108, 109, 110 are connected via hoses 112, 113, 114 respectively, to a monitored static mixer 116. Precise ratios of the latex rubber formulation, hydrogen peroxide and activating agent formulation can be delivered to the mixer 116 by metering pumps (not shown). The mixer 116 combines and mixes the latex rubber formulation, the hydrogen peroxide and the activating agent formulation. when the latex formulation, the hydrogen peroxide and the activating agent formulation are combined in the mixer 116, the activating agent immediately causes the hydrogen peroxide to begin to decompose.
The mixer 116 is connected to a flexible hose 118 for depositing the formulation of the present invention onto the primary backing 12 of the facing layer 18. The hose 120 is attached to a traversing trolley (not shown) which moves the end of the hose across the width of the facing layer 18 so that a puddle (not shown) of the latex formulation is deposited on the primary backing 12. As the facing layer 18 advances toward the take-up roll 106, the puddle of latex formulation on the surface of the primary backing 12 passes under a doctor bar 122, which shapes the latex formulation on the primary backing into a layer of a desired thickness. Thus, after the primary backing 12 passes under the doctor bar 122, the primary backing has a coating of the latex formulation of a desired thickness. Since the distance between the point where the latex formulation is deposited on the primary backing 12 and the doctor bar 122 is relatively short and since the activating agent and the hydrogen peroxide were not combined until they reached the mixer 116, only a relatively small amount of blowing occurs in the latex formulation until after it is shaped into the coating layer on the primary backing.
After the formulation is shaped into the coating layer on the primary backing 12, the hydrogen peroxide which continues to decompose, produces a sufficient amount of oxygen gas so as to convert the coating layer on the primary backing into a layer of foam 20.
Optionally, the apparatus 100 can include a bank of infrared heaters 124 disposed above the primary backing 12. The infrared heaters 124 heat the layer of latex formulation on the primary backing 12 to a temperature of approximately 150° to 600° F. By adding heat to the layer of latex formulation on the primary backing 12, blowing and curing of the latex formulation is accelerated. The use of the infrared heaters 124 permits the production speed of the carpet 10 to be increased.
Optionally, the apparatus 100 also includes heating coils 126 disposed below the conveyor 104. The heating coils 126 are connected to a source (not shown) of either heated water or steam, which is circulated through the heating coils. The heating coils 126 provide heat to the facing layer 18 disposed on the conveyor 104 and to the latex formulation coating thereon. By adding heat to the layer of latex formulation on the primary backing 12 blowing and curing of the latex formulation is accelerated. The use of the heating coils 126 also permits the production speed of the floor covering product to be increased.
Optionally, the apparatus 100 further includes a pair of nip rollers 128, 130. The nip rollers 128, 130 apply pressure to the latex foam formulation coated-primary backing 12, thereby forcing a portion of the latex formulation coating into the primary backing and into the loop backs 16 of the tufts 14, thereby improving bundle encapsulation/penetration, stitch/fiber lock, wet tuft bind, lamination strength, and dimensional stability. Optionally, the roller 130 can be an embossed roller, which can thereby imprint a desired pattern, such as a waffle pattern, in the latex foam formulation coating on the primary backing 12.
The foam-coated carpet facing layer 18 then advances through a hot air oven 132. The hot air oven 132 dries and cures the foam coating on the facing layer 18. The temperature of the hot air oven depends on the formulation used, the thickness of the foam and the speed of the production line. However, the temperature of the hot air oven 132 is about 200° F. to about 400° F.; preferably, about 240° F. to about 350° F. Residence time of the floor covering product 10 in the hot air over 132 is about 1 minute to about 10 minutes or more; preferably, about 2 minutes to about 8 minutes.
After the foam coating on the floor covering product is cured and dried in the hot air oven 132, the floor covering product advances to the take-up roll 106. The carpet 10 is then rolled into a roll and cut to length for packaging.
The following examples are intended to illustrate the present invention, but are not intended to limit the scope of the present invention as set forth in the claims.
A formulation suitable for use in the present invention is prepared as described below. Table 3 shows the latex portion of the formulation.
In Table 3 above, Synthetic Rubber latex, e.g., Butanol NS-104 cold latex, is a cold polymerized styrene-butadiene latex polymer, commercially available from BASF Corporation, Florham Park, N.J.; K-Stearate is potassium stearate; Tall Oil Soap is rosin oil, commercially available from Westvaco Corporation, New York, N.Y.; HA, High Ammonia, or LA, Low Ammonia Natural Rubber is natural rubber latex, commercially available from Firestone Natural Rubber Company, Indianapolis, Ind. Wingstay L is polymer stabilizer, commercially available from Eliochem, Akron, Ohio; Paraffin Wax emulsion is commercially available from Tiarco Chemical, Dalton, Ga.; TiO2 is commercially available from Rychem, Atlanta, Ga.; Violet blue 369/ultramarine blue is a pigment, commercially available from Organic Pigments, Spartanburg, S.C.; Whiting CC103BLK is a filler commercially available from Imerys, Roswell, Ga.; T-gum AHG Tiarco is a polyacrylate commercially available from Textile Rubber & Chemical Company, Inc., Dalton, Ga.; 30% S.S.F. is sodium silica flouride, commercially available from Lynx Chemical, Dalton, Ga.
The ingredients in Table 3 are blended together in a propeller-type mixer. The latex formulation (Table 3) is stored in tank 108 (
Table 4 shows the activating agent/accelerator portion of the formulation.
In Table 4 above, Tamol 731A is a sodium salt polyelectrolyte, commercially available from Rohm & Haas Corporation, Philadelphia, Pa.; Zinc Oxide is French process zinc oxide, commercially available from Horsehead Corporation, Monaca, Pa.; Sulfur is rubber maker sulfur, commercially available from Georgia Gulf Sulfur, Houston, Tex.; ZBDC (zinc dibutyl dithiocarbamate), ZEDC (zinc ethyl dithiocarbamate), ZBZ (zinc dibenzyldithiocarbamate) are carbamate accelerators, commercially available from R. T. Vanderbilt, Norwalk, Conn.; ZMBT is zinc mercaptobenzothiazole, commercially available from Chemtura, Waterbury, Conn.; Tall oil Soap is oleate rosin oil, commercially available from Westvaco Corporation, New York, N.Y. Octosol A-18 is a succinamate surfactant, commercially available from Tiarco Chemical, Dalton, Ga.; Octosol 571 is quaternary chloride, commercially available from Tiarco Chemical, Dalton, Ga.; Catalase enzyme is a liver-based (animal) enzyme, commercially available from Genencor International, Mocksville, N.C.; and Karaya-Gum is a thickener.
The ingredients in Table 4 are blended together in a propeller-type mixer. The activating agent/accelerator formulation (Table 4) is stored in tank 110 (
The latex formulation in tank 108, the hydrogen peroxide stored in tank 109 and the activating agent/accelerator formulation in tank 110 are fed to the monitored static mixer 116 (
The formulation makes a latex foam on the carpet primary backing 12, as described above with respect to
A formulation suitable for use in the present invention is prepared as described below. Table 5 shows the latex portion of the formulation.
The ingredients in Table 5 are blended together in a propeller-type mixer. The latex formulation (Table 5) is stored in tank 108 (
Table 4 above shows the activating agent/accelerator portion of the formulation. The ingredients in Table 4 are blended together in a propeller-type mixer. The activating agent/accelerator formulation is stored in tank 110 (
The latex formulation in tank 108, the hydrogen peroxide stored in tank 109 and the activating agent/accelerator formulation in tank 110 are fed to the monitored static mixer 116 (
The formulation makes a latex foam on the carpet primary backing 12, as described above with respect to
A formulation suitable for use in the present invention is prepared as described below. Table 6 shows the latex portion of the formulation.
The ingredients in Table 6 are blended together in a propeller-type mixer. The latex formulation is stored in tank 108 (
Table 4 above shows the activating agent/accelerator portion of the formulation. The ingredients in Table 4 are blended together in a propeller-type mixer. The activating agent/accelerator formulation is stored in tank 110 (
The latex formulation in tank 108, the hydrogen peroxide in tank 109 and the activating agent/accelerator formulation in tank 110 are fed to the mixer 116 (
The formulation makes a latex foam on the carpet primary backing 12, as described above with respect to
The same procedure is followed as in Example 1 above, except the activating agents shown in Table 7 below are used as the activating agent in the activating agent/accelerator formulation (Table 4) instead of the catalase enzyme.
The resulting tufted carpet has an integral foam backing and has excellent properties of bundle penetration and tuft lock.
The same procedure is followed as in Example 1 above, except the synthetic rubber latexes shown in Table 8 below are used as the film forming polymer in the latex formulation (Table 3) instead of the blend of styrene-butadiene and natural rubber.
The resulting tufted carpet has an integral foam backing and has excellent properties of bundle penetration and tuft lock.
A formulation suitable for use in the present invention is prepared as described below. Table 9 shows the latex portion of the formulation.
In Table 9 above, B20F Starch is unmodified corn starch from native yellow dent corn, commercially available from Grain Processing Corporation, Muscatine, Iowa.
The ingredients in Table 9 are blended together in a propeller-type mixer. The latex formulation (Table 9) is stored in tank 108 (
Table 4 above shows the activating agent/accelerator portion of the formulation. The ingredients in Table 4 are blended together in a propeller-type mixer. The activating agent/accelerator formulation is stored in tank 110 (
The latex formulation in tank 108, the hydrogen peroxide stored in tank 109 and the activating agent/accelerator formulation in tank 110 are fed to the monitored static mixer 116 (
The formulation makes a latex foam on the carpet primary backing 12, as described above with respect to
It should be understood, of course, that the foregoing relates only to certain disclosed embodiments of the present invention and that numerous modifications or alterations may be made therein without departing from the spirit and scope of the invention as set forth in the appended claims.
