Patent Application
20070277697
Before describing the present invention in detail, it is to be understood that this invention is not limited to particularly exemplified systems or process parameters that may, of course, vary. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments of the invention only, and is not intended to limit the scope of the invention in any manner.
All publications, patents and patent applications cited herein, whether supra or infra, are hereby incorporated by reference in their entirety to the same extent as if each individual publication, patent or patent application was specifically and individually indicated to be incorporated by reference.
As used herein, “moisture curable” means the catalyzed system is capable of hardening to a rigid or semi-rigid structure on exposure to moisture. Atmospheric moisture means the amount of moisture in the air, or relative humidity.
It must be noted that, as used in this specification and the appended claims, the singular forms “a,” “an” and “the” include plural referents unless the content clearly dictates otherwise. Thus, for example, reference to a “silanol” or a “crosslinking agent” includes two or more such ingredients.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the invention pertains. Although a number of methods and materials similar or equivalent to those described herein can be used in the practice of the present invention, the preferred materials and methods are described herein.
In the application, effective amounts are generally those amounts listed as the ranges or levels of ingredients in the descriptions, which follow hereto. Unless otherwise stated, amounts listed in percentage (%) are in weight percent based on 100% of the total composition.
The compositions of the present invention contain silanol fluids such as silanol end-blocked polyorganosiloxane fluids, and have a viscosity of from about 1 to about 10,000,000 centipoise measured at 25.degree. The silanol end-blocked polyorganosiloxanes useful in the compositions of the present invention are represented by the following:
wherein R1 and R 2 are independently selected from hydrogen, alkyl, alkenyl, aryl, and alkylaryl groups having 1 to 22 carbon atoms and organo-modified alkyl and aryl groups such as amino, epoxy, carboxy, or mercapto groups; and n is an integer from about 5 to about 15,000.
The silanol end-blocked polyorganosiloxanes employed in the practice of the present invention may vary from low viscosity fluids to viscous gums. Examples of silanol end-blocked polyorganosiloxanes useful in compositions of this invention include, but are not limited to, the following:
HOMe2SiO(Me2SiO)5SiMe2OH
HOMe2SiO(Me2SiO)15SiMe2OH
HOMe2SiO(Me2SiO)35SiMe2OH
HOMe2SiO(Me2SiO)283SiMe2OH
HOMe2SiO(Me2SiO)539SiMe2OH
HOMe2SiO(Me2SiO)3400SiMe2OH.
Additionally, the composition of the present invention may be comprised of more than one silanol fluid to take advantage of the range of properties attributed to various chain length silanol fluids. Low molecular weight silanol fluids for instance flow and are more easily applied to surfaces and generally have a better aesthetic look with a shiny, glossy finish. High molecular weight silanols are less greasy to the touch, are more durable, and are less likely to be removed from the surface. High molecular weight silanols by themselves, however, may be difficult to apply and manipulate on a vehicle surface. Silanol fluids such as those mentioned above are generally utilized at a concentration of 1 to 99 weight percent. Additional embodiments of the invention utilize a concentration of silanol fluids from about 30 to 50 weight percent.
Examples of high molecular weight silanol fluids useful in the present invention include but are not limited to silanol fluids with a viscosity above 500 cSt but below 10000 cSt. Higher molecular weight silanol fluids can also be used if formulated to the proper flow requirements of the particular product. Low molecular weight silanol fluids useful in the present invention include but are not limited to silanol fluids with a viscosity above 10 cSt but below 500 cSt.
The composition of the present invention includes a catalyst. Catalysts useful in the present invention include condensation reaction catalysts. More specifically, those that can facilitate a reaction when exposed to atmospheric moisture. In other words, it is strongly desired to develop a moisture curable composition which is excellent in storage stability in the sealed containers, i.e., capable of being stored under constant viscosity for a long period, rapidly curable in the presence of atmospheric moisture, and outstanding in mechanical strength after curing. The quick curing when exposed to the moisture in the air is a particular product benefit because it prevents sling, or loss of product due gravity or the movement of a treated surface such as a tire. The time required for the present compositions to cure depends upon ambient temperature, humidity, the reactivity of the groups in the presence of atmospheric moisture and the type of curing catalyst selected. Preferably, the present invention will cure under a variety of environmental conditions including conditions with higher and lower humidity, such but not limited to as about 0.5% to about 100% RH.
Examples of catalysts useful in the present invention include, metal carboxylates, metal oxides, alkyl metal carboxylates, alkyl metal alkoxides and metal chelates. More specifically, tetraalkyl titanate, tetraalkyl zirconate, dibutyltindiacetate, dibutyltindilaurate, dibutyltin dioctoate, dibutyltin dimalate, stannous octoate, tin octylate, tetrabutyl titanate, dioctyltindilaurate and tetraisopropyltitanate are examples of catalysts that may be used. In one embodiment the catalyst tetrabutyl titanate is used, which is available from E.I. DuPont Nemours & Co., Inc., Wilmington, Del., under the trademark TYZOR® TnBT.
Optionally, the present invention may include a solvent to improve the coating properties of the composition. Such a solvent should have a boiling point in the range of from 100° C. to 200° C., be capable of dissolving silanol fluids, and be selected appropriately depending on the type and amount of solute used. Solvents useful in the present invention include liquid hydrocarbons and silicone solvents. Additionally, solvents useful in the present invention include toluene, xylene, naphthene, and other aromatic hydrocarbons; 2-pentanone, 4-methyl-2-pentanone, and other ketones; isoparaffin, paraffinic alkanes, normal paraffin and other aliphatic hydrocarbons; butyl acetate, isobutyl acetate, and other esters; hexamethyldisiloxane, octamethyltrisiloxane, and other volatile silicones which may be used singly or as mixed solvents of two or more solvents. Volatility of a substance is determined when it meets the definition according to ASTM D 2369. This testing protocol measures the percentage weight loss after heating in an oven at 100° C. The amount of solvent is from 0 wt % to 99 wt %, and preferably from 30 wt % to 70 wt % relative to the total amount of the finished composition to balance the desired coating qualities with the appropriate viscosity for ease of application.
Optionally, the present invention may include a wetting agent to enhance the ability of a composition to distribute or spread across a surface treated. Wetting agents useful in the present invention include silicone surfactants, organo-modified silicones, polydimethylsiloxane fluids, and silicone polyethers.
Examples of silicone surfactants useful in the present invention include, for example, nonionic silicone-glycol copolymers, such as those available from SILWET (Witco Specialties Group, One American Lane, Greenwich, Conn.), including SILWET L-77 (silicone polyalkylene oxide-modified dimethyl polysiloxane)(CAS: 27306-78-1), SILWET L-7210, L-7220, and L-7230 (CAS: 68937-55-3) and as described in Adjuvants for Agrichemicals Ed. Foy, CRC Press (1992), and nonionic silicone polyethers, such as are available from Dow Corning (Midland, Mich.), such as Sylgard 309 (2-(3-hydroxypropyl) heptamethyltrisiloxane, ethoxylated, acetate).
Optionally, the present invention may include a crosslinking agent. Representative organosilicon crosslinking agents which may be employed include vinylmethyldiacetoxysilane, ethyltriacetoxysilane, methyltriacetoxysilane, vinyltriacetoxysilane, silicon tetraacetate, methyltriethoxysilane, methyltrimethoxysilane, dimethyltetramethoxydisiloxane, tetraethoxysilane, tetramethoxysilane, tetrapropoxysilane, bis(n-methylbenzylamido)ethoxy-methylsilane, tris(cyclohexylamino)methylsilane, vinyl tris(isopropenoxy)silane, vinyltris(methylethylketoximine)silane, and methyltris(methylethylketoxime) silane. Additional crosslinking agents include phenyl functionalized silanes, methyl functionalized silanes, organic silicates such as tetraethyl orthosilicate, or combinations thereof. The crosslinking agent is present in an amount of from about 0.1% to about 20% based on the total weight of the composition.
The composition of the present invention optionally contains one or more of the following adjuncts: stain and soil repellants, lubricants, odor control agents, perfumes, fragrances and thickeners. Other adjuncts include, but are not limited to, dyes and/or colorants, solubilizing materials, stabilizers, defoamers, preservatives, and other polymers. Thickeners, when used, include, but are not limited to, polyacrylic acid, xanthan gum, calcium carbonate, aluminum oxide, alginates, guar gum, methyl, ethyl, clays, and/or propyl hydroxycelluloses. Defoamers, when used, include, but are not limited to, silicones, aminosilicones, silicone blends, and/or silicone/hydrocarbon blends.
Additionally, the composition may include ingredients or features that optimize the timing of the catalytic reaction. This is often necessary when conditions, such as humidity or temperature are variable, and speed up or slow the reaction making it more difficult to tailor to a specific use. Examples include but are not limited to coating or encapsulating the catalyst and cure accelerators. It may also be necessary to keep the catalyst and the curable composition from coming into contact with one another until cure is desired. One approach is to formulate a two-part system in which the catalyst is in one part and the curable composition is in another part. Two part systems may utilize divided packaging or other features that prevent the mixing of the catalyst with the curable compositions separate until the reaction is needed.
Furthermore, various additives and fillers normally added to vehicle treating materials can be appropriately added to the present composition. Specifically suggested are titanium oxide, ultramarine blue, Prussian blue, zinc white, rouge, chrome yellow, lead white, carbon black, transparent iron oxide, aluminum powder, and other inorganic pigments; azo pigments, triphenylmethane pigments, quinoline pigments, anthraquinone pigments, phthalocyanine pigments, and other organic pigments; rust preventives, UV absorbers, photostabilizers, anti-sagging agents, leveling agents, and other additives; quartz micropowder, calcium micropowder, fumed titanium dioxide, diatomaceous earth, aluminum hydroxide, microparticulate alumina, magnesia, zinc oxide, zinc carbonate and combinations of the above.
The measurement of drying, curing, or skin-over, is used to determine the amount of time it takes for a composition applied to a surface to reach a non-tacky state. Useful for determining dry, cure, or skin-over time are test protocols CTM 0095 from Dow Corning's corporate test method which uses polyethylene film contact to determine the non-tacky characteristic.
The compositions are spread ⅛+/− 1/32 in. (0.32+/−0.08 cm) thick on a clean, smooth, non-porous surface and exposed to 77+/−2 F (25+/−1 C) and 50+/−4% RH. At intervals of 5 min or less a clean polyethylene strip is set on a fresh surface with a 1 oz (28.3 g) weight and left for 4+/−2 s before removing. The strip is then pulled straight up, from one end, and the time recorded when the strip pulls away cleanly from the sample. Visual inspections of the polyethylene strip determine whether the tested compositions are dry and thus pull away cleanly from the treated surface, or whether the tested compositions stick to the polyethylene strip and thus need additional drying time.
The product can be used to treat vehicle surface such as inanimate, vehicle surfaces, including tires, dashboards, leather, windows, walls, and automobiles. Other surfaces include stainless steel, rubber, glass, vinyl, leather, plastic, cloth, metal, coated metal, and chrome. In particular, the present invention can be utilized to treat automotive tires that require quick drying to prevent sling and the desire for consumers to have a glossy finish. Additionally, the product can be applied to a vehicle surface by using a device such as a spray container, pourable container, aerosol container, squeeze container, pen, brush, sponge, roller, cloth, non-woven, moldable foam, syringe, power tool, power sprayer, and combinations thereof. The product can also be contained in a package that keeps the silanol fluid separate from the catalyst until use or immediately before use.
Several specific, non-limiting, examples of products for treating vehicle surfaces in weight percent are as follows. The example compositions, described below, are intended to illustrate the sample compositions that were used to acquire experimental data on the efficacy of the protectant compositions. The compositions of this invention can be prepared by mixing the ingredients employing any suitable mixing equipment. For example one part, moisture curable compositions may be made by mixing together the silanol fluids, solvents, cross-linkers, and wetting agents (when present) and catalyst. Additional adjuncts may be added to the mixture at any desired stage, and this is preferably done as near the end of the mixing procedure as possible. It is, of course, understood that the above procedures are to be carried out in the absence of moisture in order to prevent premature curing of the compositions. This also applies to subsequent storage of the compositions. After mixing, the compositions may be stored under substantially anhydrous conditions, for example in sealed containers, until required for use.
As detailed above, the example formulas below can contain other optional adjuncts, and the protectant compositions may be applied to a surface by other suitable means than spray or aerosol applications. Tables I and II indicate that the product for treating vehicles exhibits improved levels of dry time and cures at different rates depending on the formula and the ratio of high to low molecular weight silanols.
The invention will be further illustrated by a consideration of the following examples. All parts and percentages in the examples are on a weight basis unless otherwise stated.
Although the present invention has been described in considerable detail with reference to certain preferred versions thereof, other versions are possible. For example a solvent-less system, a single silanol system, a multiple silanol system, or an aqueous based emulsion. Therefore, the spirit and scope of the appended claims should not be limited to the description of the embodied versions herein.
