Polyurethane carpet backing ingredients
A summary of ingredients and processes described in polyurethane carpet backing patents.
by Jim Vallette, Senior Researcher, Healthy Building Network, November 2010
Excerpted below –
Patent No. 7,794,814 (Sept. 24, 2010), “Polyurethane carpet backings made using hydroxymethylated polyester polyols,” filed May 4, 2006, Randall Jenkines, Dow Global Technologies (Midland, MI)
Patent No. 7,638,008 (Dec. 29, 2009), “Polyurethane roller coating process for carpet backing,” filed October 8, 2004, Hamrick et al., New Spirit Backing LLC (Dalton, GA):
Patent No. 7,241,818 (July 10, 2007), “Filler Comprising Fly Ash for Use in Composites,” filed Feb. 28, 2005, Raymond T. Hemmings, Russell L. Hill, Bruce Cornelius, Boral Material Technologies Inc. (San Antonio, TX)
Patent No. 6,916,863 (July 1 2, 2005), “Fly ash for use in polymer composites,” filed August 22, 2002, R. Hemmings, R. Hill, B. Cornelius, Boral Material Technologies (San Antonio, TX) -- essentially same as 7,241,818
Patent No. 6,743,844 (June 1, 2004), “Spill resistant carpet backing,” filed Feb. 24, 2000, Tabor et al., Dow Global Technologies Inc. (Midland, MI)
Patent No. 6,555,199 (April 29, 2003), “Carpet backing precoats, laminate coats and foam coats prepared from polyurethane formulations using fly ash,” J. Jenkines, Dow Chemical (Midland, MI). Largely identical to Pat No. 6,096,401, not repeated here.
Patent No. 6,096,401 (August 1, 2000), “Carpet backing precoats, laminate coats, and foam coats prepared from polyurethane formulations including fly ash,” filed Aug. 28, 1996, Randall Jenkines, Dow Global Technologies (Midland, MI)
Patent No. 5,908,701 (June 1, 1999), “Preparation of filled reactive polyurethane carpet backing formulations using an in-line continuous mixing process,” filed Aug. 4, 1997, J. Jennings, R. Jenkines, L. Mobley, Dow Chemical Company (Midland, MI)
[patents in italics are available in data sources section of the Pharos record, “Common polyurethane carpet backing components.”
First use of fly ash in carpet backing – Dow Patent No. 6096401: “The polyurethane-forming composition of the present invention comprises a polyol as described herein, a chain extender, a polyisocyanate, a catalyst as described herein, a surfactant, a filler wetting agent, and a filler that includes fly ash. The composition of the present invention contains reactive components such as active hydrogen containing compounds and compounds having isocyanate functionality. “
1. A+B:
“Conventional practice in the carpet manufacturing industry requires that the precoat be prepared from an isocyanate formulation (A-side formulation) and a polyol formulation (B-side formulation) at the carpet manufacturing site. This is sometimes referred to as "A+B chemistry". Preparing a polyurethane precoat by A+B chemistry can result in unpredictable loss of production and inefficiency due to problems that can occur in carrying out the reaction at the manufacturing site, such as premature gellation. “ . 6,743,844
Isocyanates and polyol blend mixed just prior to application, using catalyst.
Polyurethane is gelled and foamed with carbon dioxide gas. “The balancing of these two reactions is controlled by the natures of catalysts and auxiliary agents used in the process.” 7,638,008
“It is customary in the carpet and rug industry to use various forms of filled and unfilled latex or polyurethane to coat the back of carpet. The coating is used to bond the face fibers to the primary backing and thereby creating good tuft bind or fiber lock, and to bond secondary backing material to the greige (fibers/primary backing). … 7,638,008
“Despite the [physical property] advantages of polyurethane, cost and technical problems have kept it from widespread use in the industry as a coating, and even more rarely as a flexible foam…. 7,638,008
“When chemical agents are added to control premature polymerization and maintain viscosity to enable the polyurethane to penetrate the fibers and achieve good tuft bond and maintain adhesiveness to affix the secondary backing, the resulting mixture typically will not cure quickly without oven curing… 7,638,008
“To extend the coverage of a given quantity of pre-polymers, it is customary to add filler material to the mixture. However, filler materials are generally abrasive and complicate the application of the polyurethane mixture…. 7,638,008
“Contents of the polyol, iso and catalyst tanks are pumped to polyurethane coating head 21…. 7,638,008
2. Aqueous dispersion
“Alternatively, the polyurethane precoat may be applied as an aqueous polyurethane (PU) dispersion. Aqueous PU dispersions can be prepared by polymerizing the polyurethane reactants in an organic solvent followed by dispersion of the resulting solution in water, and optionally followed by removal of organic solvent. See U.S. Pat. Nos. 3,437,624; 4,092,286; 4,237,264; 4,742,095; 4,857,565; 4,879,322; 5,037,864; and 5,221,710, which are incorporated herein by reference. Also, an aqueous polyurethane dispersion may be prepared by first forming a prepolymer, next dispersing the prepolymer in water, and finally conducting a chain extension in the water as disclosed in WO 98/41552, published Sep. 24, 1998, which is incorporated herein by reference. Preparations of aqueous dispersions of polyurethane are also described in U.S. patent application Ser. Nos. 09/039,978 and 09/039,976. U.S. Pat. No. 4,296,159 to Jenkines, et al., discloses preparing a tufted or woven article having a unitary backing prepared by applying a polyurethane forming composition to the underside of the tufted or woven article. “ (6,743,844)
POLYOL MIXTURE
“Polyol tank contains polyol mixed with filler and surfactants, such as silicone….. “Typically, there will be between 250 and 500 parts filler per hundred parts of polyol …. “Thre may be other additives such as stabilizers, antioxidants, antimicrobials, anti-mildew agents, colorants, flame retardants, penetrants, and chain extenders, all depending upon the characteristics desired in the resulting foam…
7,638,008
“The present invention can include other components, such as surfactants, blowing agents, frothing agents, defoamers, fire retardants, pigments, antistatic agents, reinforcing fibers, antioxidants, preservatives, acid scavengers, and the like.” (6,743,844)
“Other additives may be used, including fire retardants, pigments, antistatic agents, reinforcing fibers, antioxidants, preservatives, acid scavengers, and the like. It is usually preferred not to include a blowing agent. Components are preferably dried to remove residual water. The polyurethane-forming composition preferably contains less than 0.1% by weight water, so as to avoid a gas-generating reaction with the polyisocyanate. In order to provide a non-cellular coating, it is preferred to eliminate or minimize the presence of surfactants and foam stabilizers. The elimination of these materials permits the formulation to be frothed in order to control coating weight, while then allowing the entrapped gases to escape before the formulation is cured. “ (7,794,814)
“The present invention can include other optional components. For example, a polyurethane-forming composition of the present invention can include a surfactant, a blowing agent, a flame retardant, pigments, antistatic agents, reinforcing fibers, antioxidants, preservatives, water scavengers, acid scavengers, and the like.” (6.096,401)
Polyols:
“The polyol component includes a mixture of isocyanate-reactive compounds. For, 25 to 90%, such as from 25 to 75%, from 30 to 60% or from 30 to 50%, of the total weight isocyanate-reactive compounds is one or more hydroxymethyl-containing polyester polyols. … The additional high equivalent weight polyol may be a polyether polyol, such as a polymer of ethylene oxide, propylene oxide, tetrahydrofuran or butylene oxide, or a mixture of two or more of these. Particularly suitable polyether polyols include polymers of propylene oxide, random copolymers of propylene oxide and ethylene oxide, especially those containing up to about 16% by weight randomly polymerized ethylene oxide, and oxyethylene-capped polymers of propylene oxide or propylene oxide-ethylene oxide random copolymers. These polyols are conveniently prepared by adding the corresponding alkylene oxide to an initiator material such as a low molecular weight compound containing two or more hydroxyl and/or primary or secondary amine groups. Polyester polyols such as polycaprolactone and butanediol/adipate polyesters can also be used as an additional high equivalent weight polyol. “ (7,794,814)
“Hydroxymethyl containing polyester polyol A (HMPP A) is prepared by reacting 2048.6 g (6.23 moles) of a hydroxymethylated soybean oil and 467.2 g (1.168 moles) of a difunctional, 400 molecular weight poly(ethylene oxide). HMPP A has an OH number of 71.28 and a functionality of about 2.4.
“Soy Oil Polyol A is a 130-OH-number functional blown soy oil polyol transesterified with a blend of sucrose and glycerin, sold as SoyOyl.TM. GC5N by Urethane Soy Systems Corporation.
“Polyether Polyol A is a 2000 molecular weight, nominally difunctional poly(propylene oxide). It is available commercially as Voranol.RTM. 9120A polyol from Dow Chemical.
“Polyether Polyol B is a 2000 molecular weight, nominally difunctional polypropylene oxide) end-capped with 12 percent ethylene oxide, available commercially as Voranol.RTM. 9287A polyol from Dow Chemical. “ (7,794,814)
“Polyols of the present invention are prepared by known methods by reacting an alkylene oxide with a suitable polyhydric initiator compound. The alkylene oxide preferably has 2-8 carbon atoms. For example suitable alkylene oxides can be ethylene oxide, propylene oxide, 1,2-butylene oxide, 2,3-butylene oxide, styrene oxide, epichlorohydrin, 3-methyl-1,2-butylene oxide, like compounds and mixtures thereof, with propylene oxide being the preferred oxide. The initiator compound can be a polyhydric compound such as water, ethylene glycol, propylene glycol, 1,2-butane diol, 1,3-butane diol, glycerine, trimethylol propane, p,p'-isopropylidine diphenol, aniline, ammonia, ethylene diamine, aminoethylethanolamine, like compounds and mixtures thereof. “ Dow’s example 5 includes Voranol 9741. (6,096,401)
“ Polymers of propylene oxide which are at least partially end-capped with ethylene oxide are particularly preferred. “ (5,908,701)
Filler:
The filler material can include conventional fillers such as milled glass, calcium carbonate, aluminum trihydrate, barium sulfate, fly ash, dyes and pigments or fire retardants (aluminum trihydrate and Tris polyolefin glyclol). Preferably the filler can be present in an amount ranging from 0 to 600 parts, and more preferably between 100 and 500 parts, per 100 parts of the polyol component. 7,638,008
“The present invention can include other filler materials. The filler material can include conventional fillers such as milled glass, calcium carbonate, aluminum trihydrate, talc, bentonite, antimony trioxide, kaolin, fly ash, or other known fillers. A suitable filler loading in a polyurethane dispersion can be from about 100 to about 1000 parts of filler per 100 parts of the polyurethane compound. Preferably, the filler material can be loaded in an amount of at least about 200 pph (phr), more preferably at least about 300 pph, most preferably at least about 400 pph… The inorganic fillers of the present invention include calcium carbonate, calcium sulfate, kaolin, lignite fly ash, silica, talc, feldspar, mica, glass spheres, wollastonite, aluminum trihydrate, aluminum oxide, fiber glass, similar compounds, and mixtures thereof. In the present invention, the preferred inorganic filler is calcium carbonate. .” (6,743,844)
“The polyurethane-forming composition preferably contains a filler, which reduces overall cost and may improve flame resistance and other physical properties. The filler advantageously constitutes from about 20 to about 80 percent, such from 30 to 70, 50 to 65 or 55 to 60 percent, of the total weight of the polyurethane-forming composition. Suitable fillers include talc, mica, montmorillonite, marble, milled glass granite, milled glass, calcium carbonate, aluminum trihydrate, carbon, aramid, silica, silica-alumina, zirconia, talc, bentonite, antimony trioxide, kaolin, coal based fly ash and boron nitride. “ (7,794,814)
“Calcium carbonate A is a quarried calcium carbonate ground such that 70 weight percent passes through a 325 mesh screen. It is available commercially as Georgia Marble D70 from Georgia Marble Company. “ (7,794,814)
Boral: “The filler can be a filler blend including fly ash and at least one additional mineral filler other than a fly ash. Suitable mineral fillers include calcium carbonate, aluminum trihydrate (ATH), milled glass, glass spheres, glass flakes, silica, silica fume, slate dust, amorphous carbon (e.g. carbon black), clays (e.g. kaolin), mica, talc, wollastonite, alumina, feldspar, bentonite, quartz, garnet, saponite, beidellite, calcium oxide, calcium hydroxide, antimony trioxide, barium sulfate, magnesium oxide, titanium dioxide, zinc carbonate, zinc oxide, nepheline syenite, perlite, diatomite, pyrophillite and the like, or blends thereof. In this embodiment, the additional mineral filler is preferably calcium carbonate and the calcium carbonate is preferably combined with a high fine particle content fly ash filler such as a lignite or subbituminous fly ash (e.g. having a median particle size of 10 microns or less).” (7,241,818)
“Increasing the amount of conventional fillers used in preparing carpet backing, such as calcium carbonate (CaCO.sub.3) and aluminum trihydrate (ATH), can result in an undesirable viscosity increase in a polyurethane formulation. While cost reduction can be an incentive for introducing as much filler as possible into a polyurethane formulation, it can be unacceptable to reduce the cost of production at the expense of the quality of the article produced. The amount of filler incorporated into a polyurethane formulation can be limited by the adverse effects that the filler can have on the properties of a polyurethane, such as flexibility, resiliency, and adhesion, for example. “ (6,096,401)
“The present invention includes a filler material. The filler material includes fly ash. The filler can be exclusively fly ash, or it can optionally include conventional fillers such as milled glass, calcium carbonate, ATH, talc, bentonite, antimony trioxide, kaolin, or other known fillers. Preferably, fly ash makes up at least 50 percent by total weight of the filler used in the present invention. More preferably, fly ash makes up at least 75 percent of the filler, and even more preferably at least 90 percent of the filler used in the present invention. Most preferably fly ash makes up substantially all of the filler material, i.e. at least 99 percent of the filler is fly ash. “ (6,096,401)
“The present invention includes a filler material added as a third stream (S3). In the practice of the present invention, S3 is typically added as a dry stream. The filler material can be a conventional filler, such as, for example: milled glass, calcium carbonate, aluminum trihydrate (ATH), talc, bentonite, antimony trioxide, kaolin. The filler material can also be recycled waste material from a carpet manufacturing process. For example, recycled waste material can include: fibrous materials such as lint from a fabric shearing process; and polymer waste that is ground to particle sizes less than 2 mm, including rubber from tires, and polyurethane from carpet underlays. The filler can be fly ash, or any filler or mixture of fillers known to be useful in the art of preparing filled polymers.” (5,908,701)
Fly Ash Types:
(Boral) “ a filler blend that comprises multiple types of fly ash” ; “a high fine particle content fly ash filler and a low fine particle content fly ash filler. “ ; “further comprising calcium carbonate” ; “ wherein the fly ash is selected from the group consisting of subbituminous coal fly ash, a lignite coal fly ash, a Class C fly ash, and a Class F fly ash” ; a filler blend comprising a component selected from the group consisting of subbituminous coal fly ash, a lignite coal fly ash, a Class C fly ash, a Class F fly ash, and combinations thereof. “ and/or “the filler is a filler blend comprising a first fly ash and at least one additional filler selected from the group consisting of a second fly ash and calcium carbonate, and wherein the polymer composite comprises at least one additional filler other than the fillers included in the filler blend. … The inherent properties of fly ash, or modified fly ash, allow a more economical polymer composite to be manufactured as well as one with comparable or even superior mechanical properties and performance. “ (7,241,818)