EP1765944A1

EP1765944A1 - Dry film lubricant

Info

Publication number: EP1765944A1
Application number: EP05767788A
Authority: EP
Inventors: Jasdeep Sohi
Original assignee: Henkel AG and Co KGaA
Current assignee: Henkel AG and Co KGaA
Priority date: 2004-07-02
Filing date: 2005-06-28
Publication date: 2007-03-28
Also published as: WO2006014266A1; CA2571721A1; US20060003901A1; CN1977011A

Abstract

The present invention relates to compositions and methods employing a first copolymer that is an acrylic copolymer or styrene/acrylic copolymer having a weight average molecular weight (Mw) of about 8,000 to about 14,000; a second copolymer that is an acrylic copolymer having a Mw of about 90,000 to about 130,000; a wax emulsion or dispersion, and a particulate additive. Optionally, the composition further comprises at least one of a rheological additive, ammonium hydroxide or a defoaming compound.

Description

DRY FILM LUBRICANT

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] The present application claims benefit to U.S. Provisional Application Serial Number 60/585,058, filed July 2, 2004, which is incorporated herein by reference in its entirety.

FIELD OF THE INVENTION

[0002] The invention relates generally to dry film lubricants, coatings, coated substrates, and methods related thereto.

BACKGROUND OF THE INVENTION

[0003] Metal plates or other like materials are often used to form parts, for various uses, including automotive, appliance, and general industrial uses, via stamping. Before stamping, the plates, or more broadly, substrates, are typically stored. During storage, the substrates may be exposed to conditions that can cause corrosion and/or blocking of the parts. Blocking is a surface phenomenon where two substrates adhere to each other, usually due to heat or pressure.

[0004] To prevent corrosion and blocking, it is known by those of skill in the art to apply a coating to the substrate prior to stamping. For example, mill oils, pre-lubes, drawing compounds, and dry film lubricants are valuable for preventing corrosion or reducing blocking between substrates, such as stainless steel, galvanized steel, including hot dipped galvanized steel and electro galvanized steel, galvanneal alloy, GALVALUME^® alloy (55% aluminum, 43.5% zinc, 1.5% silicon alloy steel), cold rolled steel, hot rolled steel, or aluminum.

[0005] However, while it is a goal to minimize corrosion and blocking between substrates while providing a uniform coating, the coatings must be readily removable before or during subsequent steps, such as stamping.

[0006] U.S. Patent No. 6,187,849 discloses a temporary lubricant coating which has a wax, an acid-neutralized polymer that is derived from polymerization of a ethylenically unsaturated monomer having an acid functionality and at least one different polymerizable, ethylenically unsaturated monomer, and certain amines.

[0007] Existing approaches to temporary lubricants have deficiencies. Some compositions provide adequate corrosion protection but can cause blocking. Other compositions provide a smooth coating and good scratch resistance but still allow corrosion. Thus, there is a need in the art for a dry film lubricant with improved anti-blocking and anti-corrosion properties, but which is still readily removable, such as by application of an alkaline cleaner.

SUMMARY OF THE INVENTION

[0008] The instant invention provides a product that provides good anti-blocking and good anti-corrosion properties while being able to be removed with an alkaline cleaner. In one embodiment, the present invention is directed to compositions and methods employing an acrylic copolymer or styrene/acrylic copolymer having a weight average molecular weight (Mw) of about 8,000 to about 14,000, a thermoplastic acrylic copolymer having a Mw of about 90,000 to about 130,000, water, a wax emulsion or wax dispersion, and a particulate additive. In some embodiments, a rheological additive can be used. Optionally, the composition further comprises at least one of ammonium hydroxide or a defoaming compound. DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

[0009] According to one embodiment, the present invention provides a composition, comprising a first copolymer that is an acrylic copolymer or styrene/acrylic copolymer having a weight average molecular weight (Mw) of about 8,000 to about 14,000 , a second copolymer that is an acrylic copolymer having a Mw of about 90,000 to about 130,000, water, a wax emulsion or dispersion, and a particulate additive.

[0010] In one embodiment, the first copolymer has an acid number (AN) of at least 110. In some embodiments, the acid number is between about 160 and about 220. In one embodiment, AN is about 200.

[0011] In certain embodiments, the second copolymer has an acid number of about 90 to about 130. In one preferred embodiment, the acid number is about 116.

[0012] It is understood that throughout this application, wherever a range is cited, it includes all combinations and subcombinations of ranges and specific values therein. The present invention also contemplates that acid numbers below or above the ranges cited for the first and second copolymers may be useful, provided that they produce a composition that remains relatively easy to remove with alkaline cleaner and has suitable anti-corrosion properties.

[0013] In some embodiments, the first copolymer has a glass transition temperature (Tg) of about 60 to about 80 ⁰C. In one embodiment, the Tg of the first copolymer is about 70

⁰C. In certain embodiments, the Tg of the second copolymer is about 35 to about 70 °C. In one preferred embodiment the Tg of the second copolymer is about 47 ⁰C.

[0014] In certain of these embodiments, the first copolymer is a styrene/acrylic copolymer. In some embodiments, the first copolymer has a low Volatile Organic Content (VOC). In one embodiment of the invention, the styrene/acrylic copolymer is a solid with a molecular weight of about 11,000 and an AN of about 200. [0015] Styrene/acrylic polymer compositions are commercially available. Certain of these are copolymers that are commercially available from Noveon, Inc., Cleveland, Ohio, USA, under the trade name "CARBOSET^® GA." One such product is CARBOSET^® GA-2299 copolymer which is a styrenic/acrylic copolymer having the following characteristics ascertained from publicly available sources: Total Solids: 99%; Tg: 7O⁰C; AN: 200; Molecular Weight (MW): 11000; and VOC: < 0.1%.

[0016] In some embodiments of the invention, the styrene/acrylic copolymer is a colloidal dispersion. In certain embodiments, the styrene/acrylic copolymer colloidal dispersion has total solids of about 22% to about 35%. Preferably, the total solids are about 27.5% to about 30%. Some styrene/acrylic copolymer colloidal dispersions have a Brookiϊeld viscosity of about 1000 cps to about 4000 cps. Certain styrene/acrylic copolymer colloidal dispersions are in ammonia water (ammonium hydroxide). In some embodiments, the styrene/acrylic copolymer colloidal dispersion has a pH of about 8.4 to about 9.2.

[0017] In one embodiment, the styrene/acrylic copolymer colloidal dispersion is present in a range from about 2 to about 30 percent by weight of the composition. In other embodiments, the styrene/acrylic copolymer colloidal dispersion is preferably present in an amount of about 10 to about 23 percent by weight of the composition. In one preferred embodiment, the styrene/acrylic copolymer colloidal dispersion is about 16.7 percent by weight of the composition.

[0018] In one embodiment, the styrene/acrylic copolymer colloidal dispersion is a product commercially available from Noveon, Inc., Cleveland, Ohio, USA, under the trade name "CARBOSET^® GA 2300." CARBOSET® GA-2300 is a high solids solution of a low molecular weight styrene/acrylic copolymer (CARBOSET® GA-2299) and ammonia water. CARBOSET® GA-2300 styrene/acrylic copolymer colloidal dispersion has the following characteristics ascertained from publicly available sources: Weight per Gallon: 8.9 lbs.; AN: about 190; VOC: <0.1%, along with excellent freeze/thaw stability, heat stability, and mechanical stability.

[0019] The second copolymer comprises an acrylic monomer and at least one additional monomer. Suitable acrylic monomers include methacrylic acid, acrylic acid, and their ester analogs. Suitable esters include CpC₁₂ alkyl esters. In some embodiments, the methyl, ethyl, butyl, or 2-ethylhexyl esters are preferred.

[0020] Suitable monomers for the "at least one additional monomer" useful in making acrylic compositions are well known to those skilled in the art. The additional monomer may be another of methacrylic acid, acrylic acid, or their ester analogs. Other suitable monomers include ethylenically unsaturated materials, such as styrene, vinyl toluene, and nitriles such as acrylonitrile and methyacrylonitrile, and vinyl halides. Yet other suitable monomers include crotonic acid, itaconic acid, and maleic acid.

[0021] In some embodiments, the second copolymer that is an acrylic copolymer has a low VOC. In certain embodiments, the acrylic copolymer has an AN greater than about 80. In some embodiments, the AN is about 110 to about 122. In one embodiment, the second copolymer has an AN of about 116. In some preferred embodiments, the acrylic copolymer has a Tg of about 47⁰C.

[0022] In one embodiment, the second copolymer is partially neutralized with a base. In certain embodiments, that base is preferably a volatile base such as ammonia, NH₄OH, or a primary or secondary amine.

[0023] In certain embodiments, the second copolymer is an emulsion in water. In one embodiment, the acrylic copolymer is a colloidal dispersion. Some copolymer colloidal dispersions have a molecular weight (Mw) of about 8,600 and an AN of about 116. In one embodiment, the acrylic copolymer colloidal dispersion has total solids of about 26% to about 28%. In some embodiments, the total solids is preferably about 27%. [0024] In one embodiment, the second copolymer is an acrylic copolymer colloidal dispersion that has a Brookfield viscosity of about 10 cps to about 200 cps. In some embodiments, the thermoplastic acrylic copolymer colloidal dispersion has a pH of about 7.0 to about 8.0. In some embodiments, the pH is about 7.6.

[0025] Some embodiments of the invention have the second copolymer as an acrylic copolymer colloidal dispersion present in a range from about 30 to about 70 percent by weight of the composition. In certain preferred embodiments, the acrylic copolymer colloidal dispersion is about 51.8 percent by weight of the composition.

[0026] In one embodiment, the second copolymer is an acrylic copolymer colloidal dispersion that is a product commercially available from Noveon, Inc., Cleveland, Ohio, USA, under the trade name "CARBOSET^®." In one embodiment, the product is preferably CARBOSET^® 560 acrylic colloidal dispersion. CARBOSET^® 560 acrylic colloidal dispersion is a thermoplastic acrylic copolymer having the following characteristics ascertained from publicly available sources: Total Solids (%): 26.0 to 28.0, Tg : 47° C, AN: 116, Total Solids by Volume: 24.5%, pH 7.0 to 8.0, Brookfield Viscosity, cps 10 to 200, Vapor Pressure (20 C): 2.34 kPa, % Volatile by weight: 73, VOC: Pounds per Gallon: 0.16/Grams per Liter: 20, Boiling Point (C): 100⁰C, Weight per Gallon: 8.6, Density: 1.0 to 1.2 kg/m³, MFFT: 17⁰C, and is miscible in water. While not wanting to be bound by theory, it is believed that the surface amines provide dispersion stability as water is added, and the polymer becomes more insoluble as the water content increases. The polymer contains carboxylic acid functional groups.

[0027] Water may be added even when the components are in aqueous solution. Such added water (exclusive of water in the other components), if added, may be present in an amount up to about 30 percent by weight of the composition. In some embodiments, the added water is present in a range from about 5 to about 30 percent by weight of the composition. In one preferred embodiment, the water is about 18.3 percent by weight of the composition. In contrast, the total water present, from all sources in the composition may range from about 50 to about 80 percent by weight of the composition, preferably from about 70 to about 75 percent by weight of the composition.

[0028] In one preferred embodiment, the water is deionized water.

[0029] The rheological additive can be selected from a number of conventional compositions well known to those skilled in the art. Such additives are also known in the trade as anti-settling agents. In one preferred embodiment, the rheological additive is a liquid rheological additive for aqueous coatings.

[0030] While not wanting to be bound by theory, it is believed that the rheological additive provides an anti-settling benefit. Any amount of this additive which prevents settling (i.e., maintains stability) but without rendering the composition too viscous to apply is acceptable.

[0031] In one embodiment, the rheological additive is present in a range from about 0.1 to about 1 percent by weight of the composition. In certain preferred embodiments, the rheological additive is about 0.5 percent by weight of the composition.

[0032] In certain preferred embodiments, the rheological additive is modified urea in N-methyl pyrrolidone, and is commercially available from BYK-Chemie USA Inc., Wallingford, Conn., USA, under the trade name "BYK^® 420." BYK®-420 is a liquid rheological additive, wherein after incorporation, a three-dimensional network is believed to develop. The resulting thixotropic flow behavior prevents settling and improves sag resistance. BYK®-420 rheological additive has the following characteristics ascertained from publicly available sources: Weight per Gallon: 9.33 lbs; Density at 2O⁰C: 1.12 g/mL.

[0033] Other rheological additives include Crayvallac LA- 100 available from Cray VaIIy and BYK-425 from BYK-Chemie.

[0034] In one preferred embodiment, the wax is in the form of a wax emulsion. The wax emulsion generally comprises a stable mixture of wax, emulsifier, and water. Wax comprises natural waxes, including animal waxes, for example, beeswax and lanolin, vegetable waxes, for example, carnauba and candellila, and mineral and petroleum waxes, for example, montan, paraffin, slack, scale, and microcrystalline, and synthetic wax-like substances, such as polyethylene, polypropylene, Fischer-Tropsch compounds, and resins such as ethylene-acrylic acid. In some embodiments, a wax emulsion comprises particles that are less than one micron (1 μ) in size.

[0035] In one embodiment, the wax emulsion is present in a range from about 3 to about 18 percent by weight of the composition. In one preferred embodiment, the wax emulsion is about 10.3 percent by weight of the composition. In some embodiments, the wax has a melting point in the range of 50 to 160 ⁰C. In certain embodiments, the melting point is from 55 to 110 ⁰C. In one embodiment, the wax emulsion has an melting point (Mp) of about 60 ⁰C.

[0036] In one preferred embodiment, the wax emulsion contains paraffin and polyethylene. One such a wax emulsion is commercially available from Michelman, Inc., Cincinnati, Ohio, USA, under the trade name "MICHEM^® EMULSION," and in one embodiment is preferably MICHEM^® EMULSION 62330. Other wax emulsions include those sold under the tradenames MICHEM® Lube and MICHEM^® Shield from Michelman, Inc. and Aquatec 4111 from Lawter International.

[0037] Alternatively, a wax dispersion may be used. A wax dispersion comprises micronized waxes dispersed in water. Any suitable wax emulsion or dispersion can be used, as long as it provides sufficient water repellency and formability to the composition. In some embodiments, the particles of the wax dispersion are greater than one micron in size.

[0038] In one embodiment, the particulate additive is present in a range from about 0.01 to about 4 percent by weight of the composition. In certain preferred embodiments, the particulate additive is preferably present in an amount of about 2.0 percent by weight of the composition. The particulate additive is believed to be desirable for block and corrosion resistance, and greater amounts can be used, provided there is no negative effect on stability of the composition. [0039] In one embodiment, the particulate additive is clay or silicate. In some compositions, the silicate includes at least one of Mg or Al. In one embodiment, the particulate additive is a magnesium silicate.

[0040] In another embodiment, the particulate additive is talc. The talc may be, for example, hydrous magnesium silicate, and is commercially available from Reade Advanced Materials, Providence, Rhode Island, USA. Talc is also known as talc powder, cosmetic talc, French talc, Montana talc, Texas talc, Vermont talc, industrial talc, tremolitic talc, steatite talc, fibrous non-tremolite talc, no asbestos talc, magnesium silicate talc, talcum, French chalk, talc (Mg₃H₂(SiOs)₄).

[0041] Commercial products include Nytal® 300, a talc marketed by Lansco Colors, and reported to have a median diameter of 6.9 microns. Other Nytal® talcs are reported to have mean diameters of 4.5, 7.0, 8.7, and 12.6 microns. The Nytal® talcs are believed to be a mixture of platy and needle shaped particles. Another commercial product is Artie Mist®, a platy talc available from Luzenac America that has a mean diameter of 2.2 microns. Nicron® 402, available from Luzenac America, is a platy talc having a mean diameter of 10 microns. Vertal® 92, available from Luzenac America, is a larger diameter talc with a platy structure. The mean diameter of these particles is 17.5 microns.

[0042] In some embodiments, the particulate is a plate shape. In other embodiments, the particulate is needle shaped. In certain preferred embodiments, the particulate is a mixture of the two shapes.

[0043] Some preferred particles have a mean particle size of about 0.5 to about 3 microns. Such preferred particles may have a mean particle size of about 2 microns. Other particles have a mean particle size of about 5 to about 25 microns. One example of such particles has a mean diameter of about 6.9 microns, another has a mean diameter of about 17 microns. In some preferred embodiments, it is desirable to have a mixture of the smaller and larger particles detailed above. Such a mixture has been observed to provide better resistance to the fingernail scratch test and anti-blocking characteristics than either type of particle does by itself.

[0044] According to another embodiment of the present invention, the composition further comprises a viscosity builder. In one embodiment, the viscosity builder is a base. The amount of the base required is that sufficient to neutralize the acid functional groups on the copolymers, which is readily calculable by one of skill in the art. One suitable viscosity builder is ammonium hydroxide. One commercial source of ammonium hydroxide is known by the product name "Ammonium hydroxide 26 Be" from Univar USA, Kirkland, WA, USA 98003. Ammonium hydroxide 26 Be is also known as "aqua ammonia water," and typically contains between 28% to 30% ammonia before dilution. Another source of ammonium hydroxide is Sigma-Aldrich.

[0045] In some embodiments, the ammonium hydroxide is present in a range from about 0.01 to about 0.8 percent by weight of the composition. In one preferred embodiment, the ammonium hydroxide is about 0.4 percent by weight of the composition.

[0046] In an alternative embodiment of the present invention, the ammonium hydroxide can be replaced with alkali bases or amines, for example 2-aminomethyl-propanol (AMP), morpholine, dimethyl ethanol amine (DMEA).

[0047] According to other embodiments of the present invention, the compositions further comprises a defoaming compound. Many defoamers are know to those skilled in the art and can be used so long as their use does not negatively impact other product properties. Suitable defoaming compounds include compositions that comprise straight chain petroleum distillates, silica, surfactants, and/or wax. In one embodiment, the defoaming compound comprises about 80% to about 90% straight chain petroleum distillates, about 1% to about 10% silica, about 1% to about 10% surfactants, and about 1% to about 10% wax.

[0048] One preferred defoaming compound is a product commercially available under the trade name "HYDRO SPEC DO-IOl" available from Henkel Surface Technologies, Madison Heights, MI, USA, having a pH 6.5 to 7.5 (of concentrate), viscosity at 25⁰C: 800 cps to 2000 cps, and specific gravity: 0.85 to 0.90. Other oil-based defoamers include those sold under the tradename Hi-Mar by the Thornley Company, and FOAMASTER SA-3 available from Fritz Chem Corporation.

[0049] One or more coalescing agents may be added to the instant composition. Suitable agents include low molecular weight ethoxylated alcohol and propylene glycol esters of fatty acids. One preferred agent is an aromatic alkoxylated ester such as, for example, an ethoxylated benzyl alcohol. Suitable commercial products include Archer RC®, CAS # 515152- 38-2, from ADM. This product is derived from sunflower or corn oil fatty acids with propylene glycol. Another agent is Genapol BA 040, a benzyl alcohol ethoxylate, CAS # 26403-74-7, available from Clariant. In one preferred embodiment, a mixture of ethoxylated alcohol and propylene glycol esters of fatty acids is used.

[0050] In yet another embodiment, the present invention provides a coating comprising any of the compositions described above where the compositions having been dried in place to remove water and any other volatiles present. Preferably the composition is applied by any conventional means known in the art and is then dried. In one embodiment, the coating does not react with the substrate, nor does it oxidize, but maintains its original applied characteristics.

[0051] In another embodiment, the composition of the present invention can be diluted with water to provide any desired coating weight required for protection under most storage conditions. The temporary protective coating of the invention may be applied to metallic substrates by any conventional application means known in the art such as spraying, brushing, dipping, roll coating, curtain coating or the like. The coating is typically applied at film weights of 100 to 600, preferably 150 to 500, and more preferably 200 to 350 milligrams per square foot. Coating weights are typically in the range from about 150 mg/ft² to 300 mg/ft².

[0052] Applied temporary protective coatings can be air dried or force dried. Typically, the applied coatings are forced dried at temperatures ranging from 5O⁰C to 25O⁰C, preferably from 7O⁰C to 200⁰C, and more preferably from 9O⁰C to 15O⁰C. In yet another embodiment, once applied the coating of the present invention can be dried by achieving surface temperatures less than 200° F, and in a presently preferred embodiment as low as 170° F.

[0053] In a preferred embodiment, this coating can be removed by alkaline cleaning, but is advantageously not water-soluble. Once removed, the surface is available for further processing. Removal of the applied coating is effected by contacting the coated substrate with an aqueous alkaline solution, such as by spraying, flooding, immersion or the like.

[0054] In still another embodiment, the present invention provides a substrate contacted by any of the compositions described above. In one embodiment, the substrate may be stainless steel, galvanized steel, hot dipped galvanized steel, electro galvanized steel, galvanneal alloy, GALVALUME^® alloy (55% aluminum, 43.5% zinc, 1.5% silicon alloy steel), cold rolled steel, hot rolled steel, or aluminum.

[0055] According to yet another embodiment, the present invention provides a method for preventing corrosion on a substrate, comprising contacting the substrate with any of the compositions described above. In another embodiment, the present invention provides a method for reducing blocking between substrates, comprising contacting the substrates with any of the compositions described above.

[0056] The present invention provides, in one embodiment, a composition, comprising a copolymer comprising at least one of styrene/acrylic or acrylic, a thermoplastic acrylic copolymer, water, a rheological additive, a wax emulsion, a particulate additive, and a viscosity builder.

[0057] In yet another embodiment, the present invention provides a composition, comprising a styrene/acrylic copolymer colloidal dispersion, a thermoplastic acrylic copolymer colloidal dispersion, water, a urea-containing rheological additive, a wax emulsion, a silicate including at least one of Mg or Al, and ammonium hydroxide. [0058] The present invention also provides a composition comprising CARBOSET

GA-2300 copolymer, water, a rheological additive, a particulate additive, a viscosity builder, a wax emulsion, and CARBOSET 560 copolymer.

EXAMPLES

Example 1

[0059] A dry film lubricant was prepared having the components listed in TABLE 1.

TABLE 1

[0060] While not wishing to be bound to any theory of operation, the composition functions without the talc and the ammonium hydroxide, and so these components are optional. The pH of the composition should be 7 or greater.

Example 2

[0061] The composition from TABLE 1 was characterized using conventional methods. Liquidform

[0062] The viscosity of the composition as measured in a #2 Zahn Cup was 32-34 seconds. A free flowing liquid was observed after placing the composition in a sealed container at 100⁰F for a predetermined time period, thus showing good storage stability. Coated Panels

[0063] Cold rolled steel substrate panels were coated with the composition from TABLE 1 by using a drawdown bar. The coating weights, determined via the Weigh Strip Weigh method using methylethyl ketone (MEK), were 220-260 mg/sqft.

[0064] Water spotting was tested by placing a drop of water on the coated panel and observing for staining. No staining on coated panels was observed during the thirty minute water drop test.

[0065] IT bend tests were performed using ASTM D4145. The test used a hand-operated die. The panels were then taped with Scotch tape at the location of the bend, the tape was removed and the bend radii were wiped with copper sulphate to see if the coating was removed by the tape. Very light copper sulfate stain was observed after removal of the tape.

[0066] Reverse Impact Tests were performed as in ASTM D2794. All the panels were subjected to impact of a ball at 80 inch/pounds. After impact, the panels were taped at the bend or dent, the tape was removed and bend radii were then wiped with copper sulfate to see if the coating was removed by the tape. Very light copper sulfate stain after taping was observed.

[0067] The composition was cleanable with PCL 75 LC as per TPB 232070 (2% solution of PCL 75 LC in water @ 110° F for 60 sec). To determine whether there was any residue of the dry lubricant on the panels, the substrate panels were cleaned, then rinsed with deionized water and dried. A drop of about 3 Wt % copper sulfate pentahydrate solution was dropped on the panels. A 100% reaction, evidenced by the area of the panel that contacted the drop turning black within a second of contact, was observed on all the panels, indicating the panels were fully cleaned and were water break free.

[0068] The composition performed satisfactorily when formed, as evidenced by formability testing, such as determining limiting dome height (LDH) using a MTS Metalform 866 LDH Machine. This test was performed by contacting the panel with a die to see how far the surface could deform without disrupting the coating. [0069] The testing showed that the composition had acceptable properties for a dry film lubricant, and performed at least as well in the above tests as a commercially available dry film lubricant sold under the trade name "CHEMFORM^®" available from PPG Industries, Inc. Pittsburg, PA, USA. In particular, the competitive product showed very light copper sulfate stain in the IT bend test and reverse impact test. The competitive product showed no staining in the water spotting test.

Example 3

[0070] The composition from TABLE 1 and the comparative dry film lubricant were each tested in a 24 hour stack test.

[0071] Cold rolled steel substrate panels were coated using either the composition from TABLE 1 or the comparative dry film lubricant. Like-coated panels were clipped face to face with paper clips and placed in a beaker over water, but not sitting in the water. The beaker was covered with plastic and taped shut, and then placed in an oven at 100⁰F for 24 hours.

[0072] Panels coated with the composition from TABLE 1 showed no haziness, corrosion, or stickiness.

[0073] Panels coated with the comparative dry film lubricant were very hard to take apart and showed 80-90% haziness. It is not desired for the panels to show any corrosion or blocking as it will be hard to uncoil the coils after sitting in the hot and humid atmosphere.

Example 4

[0074] The composition from TABLE 1 and the comparative dry film lubricant were each tested in a Blocking Test using Carver hydraulic equipment at 5000-6000 psi at 14O⁰F. The object of the test was to determine and compare blocking (panels sticking together to form a block as representing coiled) of panels coated with different coatings. [0075] For the blocking test, 2" X 4" strips are cut from the panels where both sides were coated with organic passivate. To test for blocking the Carver hydraulic press used for T- bends was equipped with constant temperature heating blocks attached to variants. The variants were adjusted as necessary to maintain a constant temperature as measured by a VWR dual input J-type thermocouple. Panels were tested face to face in pairs with three pairs on the press at any one time. The press was to set to approximately 5000 lbs for 30 minutes. Pressure was observed to stay between 5000-6000 lbs during the course of the blocking test. Panels were tested at different constant temperatures between 110-140⁰F. After 30 minutes the panels are removed from the press, allowed to cool and observed for blocking behavior. The panels passed the blocking test at that temperature if the panels fell apart easily and there is no sound when separating panels.

[0076] Cold rolled steel substrate panels were coated using either the composition from TABLE 1 or the comparative dry film lubricant. Panels coated with the composition from TABLE 1. showed no blocking at 14O⁰F. Panels coated with the comparative dry film lubricant showed some blocking at 13O⁰F,

Example 5

[0077] The composition of Example 1 was prepared where the talc (17.5 micron mean diameter) was replaced with 1% each of the Artie Mist® and Nytal 300. In addition, 1% each of the BA040 and Archer RC were added to the composition.

Example 6

[0078] The composition of Example 5 was tested for performance by a variety of tests described below. The coating was applied to the cold rolled steel panels using a drawbar. The results are presented in Table 2. The column labeled "Performance Criteria" represents properties desired for use of dry film lubricants in commercial applications, such as automotive, appliance, and general industrial uses .

Table 2

[0079] Thus, it is believed that compositions of the present invention are surprisingly better anti-corrosive and anti-blocking compositions than known compounds.

[0080] The disclosures of each patent, patent application, and publication cited or described in this document are hereby incorporated herein by reference, in their entireties.

[0081] Various modifications of the invention, in addition to those described herein, will be apparent to those skilled in the art from the foregoing description. Such modifications are also intended to fall within the scope of the appended claims.

Claims

What is Claimed:

1. A composition, comprising:

~ a first copolymer that is an acrylic copolymer or styrene/acrylic copolymer having a weight average molecular weight (Mw) of about 8,000 to about 14,000;

—a second copolymer that is an acrylic copolymer having a Mw of about 90,000 to about 130,000;

~ water;

— a wax emulsion and/or wax dispersion; and

— a particulate additive.

2. The composition of claim 1, wherein said first copolymer is present in a range from about 10 to about 23 percent by weight of the composition.

3. The composition of claim 1, wherein said second copolymer is present in a range from about 30 to about 70 percent by weight of the composition.

4. The composition of claim 1, wherein said water is present in a range from about 5 to about 30 percent by weight of the composition.

5. The composition of claim 1 additionally comprising a rheological additive.

6. The composition of claim 1, wherein said rheological additive is modified urea in N- methyl pyrrolidine and is present in a range from about 0.1 to about 1 percent by weight of the composition.

7. The composition of claim 1 comprising a wax emulsion that comprises paraffin and polyethylene.

8. The composition of claim 7, wherein said wax emulsion is present in a range from about 3 to about 18 percent by weight of the composition.

9. The composition of claim 1, wherein said particulate additive is a silicate.

10. The composition of claim 1, wherein said particulate additive is a silicate including at least one of Al or Mg.

11. The composition of claim 1, wherein said particulate additive is talc.

12. The composition of claim 11, wherein said talc is present in a range from about 0.01 to about 4 percent by weight of the composition.

13. A coating comprising the composition of claim 1.

14. A substrate contacted by the composition of claim 1, wherein the substrate is stainless steel, galvanized steel, hot dipped galvanized steel, electro galvanized steel, galvanneal alloy, alloy steel comprising 55% aluminum, 43.5% zinc, and 1.5% silicon, cold rolled steel, hot rolled steel, or aluminum.

15. A method for reducing blocking between substrates, comprising contacting said substrates with the composition of claim 1.

16. The method of claim 15 wherein the coating is dried using surface temperatures lower than about 200° F, and as low as about 170° F.

17. A composition, comprising:

~a second copolymer that is an acrylic copolymer having a Mw of about 90,000 to about 130,000;

~ water;

~ a wax emulsion;

— a particulate additive; and ~ a viscosity builder.

18. A composition, comprising:

— a styrene/acrylic copolymer colloidal dispersion;

~ a thermoplastic acrylic copolymer colloidal dispersion; — water;

~ a urea-containing rheological additive; ~ a wax emulsion;

— a silicate including at least one of Mg or Al; and ~ ammonium hydroxide.

19. The composition of claim 18, further comprising a defoaming compound.

20. The composition of claim 18, wherein said silicate is talc.