CA2128753A1 - Water-based coating composition - Google Patents
Water-based coating compositionInfo
- Publication number
- CA2128753A1 CA2128753A1 CA 2128753 CA2128753A CA2128753A1 CA 2128753 A1 CA2128753 A1 CA 2128753A1 CA 2128753 CA2128753 CA 2128753 CA 2128753 A CA2128753 A CA 2128753A CA 2128753 A1 CA2128753 A1 CA 2128753A1
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- CA
- Canada
- Prior art keywords
- water
- coating composition
- based coating
- composition
- thickener
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Classifications
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- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
- C09D125/00—Coating compositions based on homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an aromatic carbocyclic ring; Coating compositions based on derivatives of such polymers
- C09D125/02—Homopolymers or copolymers of hydrocarbons
- C09D125/04—Homopolymers or copolymers of styrene
- C09D125/08—Copolymers of styrene
- C09D125/10—Copolymers of styrene with conjugated dienes
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- Chemical & Material Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Wood Science & Technology (AREA)
- Organic Chemistry (AREA)
- Paints Or Removers (AREA)
Abstract
The present invention provides a water-based coating composition for metal substrates, such as steel surfaces. The water-based coating composition of the present invention includes a styrene-butadiene emulsion, a filler, and a thickener in amounts capable of producing a composition having a viscosity of at least about 3000 Centipoise.
Description
212~7~3 ~VAT~R-BASED COATING COMPOSITION
- Field of the Invention - The present invention provides a water-based coating composition for 5 metal substrates, such as steel surfaces. Specifically, the present invention provides a water-based coating composition that provides resistance to abrasion, e.g., chipping or cracking, and preferably resistance to environmental attack, e.g., corrosion.
Back~round of the Invention Various coating compositions for metal substrates, such as steel surfaces, are commercially available. These include, for example, oil-based red lead primers, zinc chromate-based alkyd primers, inorganic zinc-rich primers, organic zinc-rich primers, aluminized epoxy mastics, coal tar mastics, and asphalt- or petroleum-based resins. These coating compositions typically include organic solvents; however, it is generally desirable to use aqueous formulations in place of organic solvent formulations. Organic solvent formulations use expensive and toxic fl~mm~'~ le solvents, which must be captured upon drying the formulation to prevent air pollution.
The use of organic solvents usually generates higher costs and requires suitableexplosion-proof handling and exhaust systems. Furthermore, volatile organic solvents can pose health and safety problems.
Several aqueous-based, i.e., water-based, coating compositions for metal surfaces are known. For example, Trousil (U.S. Patent No. 4,282,131, issued August 4, 1981) discloses a water-based undercoating composition containing a butadiene-styrene latex emulsion. However, this coating composition will not adhere to painted substrates. Furthermore, it cannot be baked without previously air drying, which is often desirable in automobile applications. Generally, most water-based coatings that are baked, without being previously air dried, blister. This is particularly true if a thick coating is desired, i.e., greater than about 20 mils (0.5 mm) on a wet coating basis.
Most commercially available products, whether solvent-based or water-based, serve essentially as a primer or an undercoat for corrosion resistance to which a later paint layer is applied. They do not necessarily provide sound-proofing, nor are they typically resistant to abrasion, e.g., chipping or cracking. Once many of the 2I287~3 commercially available coatings are cut or chipped and the underlying steel surface is exposed, oxidation can occur, which can lead to further "undercutting" of thecoating. That is, the rusting process can begin at the exposed surface and spread such that the rusting process proceeds beneath the coating. Thus, many commercially S available coating compositions cannot be used in environments where the coating is subject to impact or abrasion, particularly if corrosion resistance is desired.
Summary of the Invention The present invention provides a water-based coating composition for metal substrates, such as steel surfaces, that provides resistance to abrasion. It can be used wherever a hard, durable, abrasion resistant coating is needed. It is particularly useful for coating vehicles or vehicle parts, such as the underbodies of cars. It can also be used in coating appliances or other pieces of metal furniture.
Advantageously, preferred embodiments of the water-based coating composition canprovide corrosion resistance and/or sound deadening characteristics. Particularly preferred embodiments of the water-based coating composition can be baked at a temperature of about 200-300F (93-149C) at high film thicknesses, i.e., at least about 20 mils (0.5 mm) on a wet coating basis, with little or no prelirninary air drying. Advantageously, such baked coatings exhibit little or no blistering.
In its broadest sense, the water-based coating composition of the present invention includes a styrene-butadiene emulsion, an effective amount of a filler, and an effective amount of a thickener. As used herein, "an effective amount" is an amount capable of producing a composition having a viscosity of at least about 3000 Centipoisem under ambient conditions. Preferably, the viscosity is at least about 15,000 Centipoise and no greater than about 50,000 Centipoise, under ambient conditions. Particularly preferred embodiments of the invention include a water-based coating composition, and a coating prepared therefrom, that include about 10-50 wt-% styrene-butadiene emulsion, about 30-70 wt-% filler, and about 0.1-3 wt-%
thickener, wherein the water-based coating composition has a viscosity of at least about 3000 Centipoise, under ambient conditions, and a solids content of about 60-80 wt-%.
2l28753 -Also included within the scope of the invention is a method of treating a vehicle for resistance to environmental attack. -This method includes coating the underbody of the vehicle with a water-based coating composition as described above and curing the coating. The composition preferably includes about 10-50 wt-%
styrene-butadiene emulsion, about 30-70 wt-% filler, about 0.1-3 wt-% thickener,about 0.05-1 wt-% defoaming agent, and about 0.1-2 wt-% dispersant. This preferred water-based coating composition has a viscosity of at least about 15,000 Centipoise and a solids content of about 60-80 wt-%. Although the coating composition can be cured upon air drying for 72 hours or more, preferably, and advantageously, it can be cured upon baking the composition at a temperature of about 200-300F (93-149C).
Detailed Description of the Invention The present invention provides a water-based coating composition that can be used wherever a hard, durable, abrasion-resistant, i.e., chip-resistant, coating is needed. For example, it can be used in coating automobile parts, particularly the underbodies of cars, trucks, etc. It can also be used in coating appliances or other pieces of metal furniture. Advantageously, preferred embodiments of the water-based coating composition can additionally provide corrosion resistance and/or sound deadening characteristics. Generally, a good chip-resistant and corrosion-resistant coating composition should be one that forms a coating that is resistant to chipping, cracking, or cutting, and is resistant to moisture. Advantageously and preferably the composition should also have a relatively high solids content, i.e., greater than about 70 wt-%, to provide additional insulation from noise.
The water-based coating composition of the present invention includes a unique combination of a styrene-butadiene (SBR) emulsion, a filler, and a thickener.
The ratio of SBR:filler:thickener can be adjusted to produce a composition having an appropriate viscosity such that a dry coating of at least about 15 mils (0.4 mm) or a wet coating of at least about 20 mils (0.5 mm) can be produced. Typically, these components are used in amounts effective to produce a composition having a viscosity of at least about 3000 Centipoise, under ambient conditions. Preferably, these components are used in amounts effective to produce a composition having a viscosity 2I ~875~
of at least about 15,000 Centipoise, and more preferably no greater than about 50,000 Centipoise~ under ambient conditions. As used in this context, ambient conditions refers to atmospheric pressure and a temperature of about 20-30C (i.e., room temperature).
5The solids content of the compositions of the present invention are typically and preferably about 60-80 wt-%. For formation of a coating with advantageous corrosion resistance and antichip characteristics, the solids content need only be about 60-70 wt-%; however, if a composition is also to impart sound deadenin~ characteristics to a coating as well, the composition preferably has a solids 10content of about 70-80 wt-%. The filler contributes significantly to the solids content of the compositions. Optional components, such as a pigment, can also contribute to the solids content of the composition.
As used herein, a corrosion-resistant coating is one that withstands a salt spray test as described by ASTM B117 (American Society of Testing and Materials,151985) for at least about 168 hours. By this it is meant that a steel workpiece with a coating of the present invention exhibits substantially no corrosion or undercutting within a 168-hour period on cold rolled steel or a 500-hour period on primed steel.
Preferably, the corrosion-resistant coating of the present invention withstands the ASTM B117 salt spray test for at least about 300 hours on cold rolled steel, and20more preferably for at least about 500 hours on cold rolled steel.
As used herein, a chip-resistant coating, i.e., an antichip coating, is one that withstands a chip test as described by SAE J400 (Society of Automotive Engineers, June, 1980) with a rating of no less than about 5 on a scale of 1-10. By this it is meant that a steel workpiece with a coating of the present invention does 25not substantially chip the coating and expose the bare metal. Preferably, the chip-resistant coating of the present invention has a rating of no less than about 7, and more preferably, no less than about 9, according to this test procedure.
As used herein, a sound-deadening coating is one that has a sound decay of at least about 11 db/sec according to a Geiger Plate test as described by the30Method of Geiger & Hamme of Ann Arbor, MI. Preferably, the sound-deadening coating of the present invention has a sound decay of at least about 20 db/sec, and 212~7~3 more preferably, a sound decay of at least about 30 db/sec, according to this test .procedure. - - -Generally, water-based coatings are air dried. However, in certain applications, such as in the automotive industry it is advantageous to be able to bake S the coating. Typically, water-based coatings having a thickness of about 20 mils (0.5 mm) wet, or more, cannot be baked without first being air dried or flashed. Thisis problematic at least because of the time involved in the air drying.
Advantageously, preferred compositions of the present invention can be baked at a temperature of about 200-300F (93-149C) substantially immediately, i.e., within 10 about 1 hour of applying the coating, without causing blisters. That is, with little or no air drying, preferred compositions of the present invention can be baked without detrimentally affecting the integrity of the coating.
Generally, water-based underbody coating compositions are applied after the workpiece, i.e., automobile, is primed and painted. Therefore, the compositions 15 must adhere to the paint. Generally, however, conventional water-based coating compositions do not adhere well to paint (base coat and/or clear coat) in cold conditions. Furthermore, typical conventional water-based coating compositions cannot be applied under the paint and withstand the baking step of the primer and painting operation. Advantageously, preferred water-based coating compositions of the present 20 invention can be applied under paint and withstand baking temperatures. Other water-based coating compositions of the present invention can be applied over paint with good adhesion. Typically, these compositions are air dried. Some compositions ofthe present invention can be applied either under or over paint.
25 Styrene-Butadiene Emulsion The major component of the composition of the present invention is a styrene-butadiene (SBR) emulsion, i.e., a copolymer of styrene and 1,3-butadiene.
The SBR emulsion is the major binder and film former of the composition. It is responsible for imparting flexibility to the coating composition as well as resistance 30 to abrasion, e.g., chipping. Suitable SBR emulsions are those that have a bound styrene content of about 60%. Such emulsions are comrnercially available.
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Examples of suitable SBR emulsions Include, but are not limited to:
ArolonTM 870 (EA-6556) styrene-butadiene emulsion available from Reichhold Chemicals, Inc. (Research Triangle Park, NC); Styrofan ND 593 carboxylated styrene-butadiene dispersion available from BASF Corporation (Chattanooga, TN); and Good-5 Rite Latex No. 1800-X-73 available from B.F. Goodrich Company (Akron, Ohio).
Preferably, the compositions of the present invention include ArolonTM 870 (EA-6556) styrene-butadiene emulsion.
Generally, the SBR emulsion is present in an amount effective to impart desirable properties to the composition. In preferred compositions, the styrene-10 butadiene emulsion is present in an amount of about 10-50 wt-%, and more preferably in an amount of about 15-45 wt%.
Fillers The solids content of the composition is primarily the result of a filler.
15 The filler also contributes to improved chipping resistance and sound barrierproperties. Preferred fillers also contribute to corrosion protection. Suitable fillers include, but are not limited to calcium/magnesium carbonates, calcium carbonates, aluminum silicates, talc (i.e., magnesium silicates), mica (i.e., a variety of silicates), barytes (barium sulfate), clay (i.e., aluminum silicates), sodium potassium alumina 20 silicate, and metal phosphates such as zinc phosphate.
A combination of various fillers can be used in the water-based coating compositions of the present invention to impart a variety of properties to the coatings.
For example, when a coating with a high level of chipping resistance is desired, the composition preferably includes a combination of calcium/magnesium carbonate and25 talc. When a coating with a high level of corrosion protection is desired, the composition preferably includes a combination of a metal phosphate, e.g., zinc phosphate, and mica or talc. When a coating with a high level of sound deadeningis desired, the composition preferably includes a combination of any of the following fillers: calcium/magnesium carbonates, calcium carbonate, talc, mica, or barytes.
30 In the most preferred compositions of the present invention, however, the filler is a non-mica containing filler.
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-In preferred compositions, the filler is present in an amount of at least about 25 wt-%. More preferably, the filler is present in an amount of about 25-70 wt-%. For applications in which the composition is baked to form a cured coating, the filler is preferably present in an amount of about 25-50 wt-%. Generally, the 5 lower the solids content the longer the baking time required for complete cure of the composition. For applications in which the composition is air dried to form a cured coating, the filler is preferably present in an amount of about 30-70 wt-%.
Thickeners The compositions of the present invention also include an effective amount of a thickener. The thickener is used to build flow resistance, viscosity, and gel characteristics. Generally, a composition with optimal gel characteristics produces a more consistent and uniform coating, i.e., one that does not easily run or sag.
Suitable thickeners include clay, magnesium/aluminum silicates, acrylates, xanthum 15 gum, and the like. Examples include, but are not limited to, Acrysol(~ TT-6 15 acrylic polymer emulsion available from Rohm and Haas Company (Philadelphia, PA), Attagel(~) mineral thickener (hydrated magnesium aluminum silicate) available from Engelhard Corporation (Edison, NJ), BentoneTM LT organoclay thickener available from NL Chemicals, Inc. (Hightstown, NJ). Preferably, the compositions of the 20 present invention include an acrylate thickener, a magnesiumlaluminum silicate thickener, or clay. More preferably, they include an acrylate thickener such as Acrysol~ TT-615 acrylic polymer emulsion at least because it provides excellent gel characteristics. Most preferably, certain compositions of the present invention include a combination of an acrylate thickener, such as Acrysol(~ TT-615 acrylic polymer25 emulsion, and a magnesium/aluminum silicate thickener, such as Attagel(~) mineral thickener.
In preferred water-based coating compositions of the present invention, the thickener is present in an amount of at least about 0.1 wt-%. More preferably, the thickener is present in an amount of no more than about 3 wt-%. For 30 applications in which the composition is baked to form a cured coating, the thickener is present in an amount sufficient to produce high gel characteristics such that a coating with a textured finish is formed when spray applied. A textured finish has ~2~753 -a higher surface area and releases water faster in a baking process. Generally, for baking applications, the thickener is preferably present in an amount-of about 2-3 wt-%. For applications in which the composition is air dried to form a cured coating, the thickener is preferably present in an amount of about 0.1-1 wt-%. Generally, the 5 thicker a coating thickness desired, the more thickener is included in the composition.
Miscellaneous Components Various other optional ingredients can be added to the composition without affecting or altering the desired characteristics of the composition. Certain 10 ingredients can be added to improve various characteristics of the composition and resultant coating, such as corrosion resistance, for example. Such ingredients include, for example, secondary film formers, defoaming agents, dispersants, surfactants,pigments, preservatives, and pH adjusters.
It is to be understood that any individual component used in the 15 compositions of the present invention can be used to perform various functions. For example, as seen above, clay can be used as both a thickener and a filler. Pigments can be used as fillers and to merely impart color.
The compositions of the present invention include a styrene-butadiene emulsion as the primary film former and binder. Additional, i.e., secondary, film 20 formers can also be included in the composition to enhance the formation of auniform coating. Furthermore, components can be added to the composition to enhance adhesion properties. Certain secondary film formers can be added that enhance both film formation and adhesion properties. For example, the composition can include a vinylidene chloride emulsion, such as a vinylidene chloride/vinyl 25 chloride/aclylic emulsion, that is designed for use in compositions that do not have good adhesive properties. The water-based coating compositions of the present invention preferably include an amount of a secondary film former effective to enhance adhesion and corrosion protection. More preferably, a secondary film former is used in an amount of no more than about 15 wt-%. Most preferably, it is present 30 in an amount of about 1-15 wt-%.
- Defoaming agents are preferably used in the water-based coating compositions of the present invention to prevent, or reduce the amount of, foaming ~12~753 -g during formulation and application. Typical defoarning agents are well known in the water-based paint industry. The water-based coating compositions of the present invention preferably include an amount of a defoaming agent effective to keep the amount of foam produced during formulation to a low level such that it does not 5 adversely affect the perforrnance properties of the coatings of the present invention.
Preferably, the water-based coating compositions of the present invention include about 0.05-1 wt-% of a defoaming agent.
Dispersants and surfactants can be used in the compositions of the present invention to assist in the dispersion of fillers, pigments, emulsions, etc.
10 Suitable dispersants and surfactants include inorganic polyphosphates such as potassium tripolyphosphate (K5P30,o), organic polyacids, and nonionic difunctional block copolymers. Preferably, a dispersant or surfactant is used in an amount effective to provide good wetting of the solids so that a homogeneously dispersed composition is formed that can be generally evenly applied to surfaces at a variety 15 of thicknesses. More preferably, a dispersant or surfactant is used in an amount of about 0.1-2 wt-%, and most preferably in an amount of about 1 wt-%.
A pigment can also be used in the compositions of the present invention to provide color. As discussed above, pigments can also be used to increase the solids content of the compositions and perform the function of a filler, for example.
20 Preferably, the pigment is black as the compositions are typically used for undercoating automobiles. Generally any inorganic or organic pigment can be used in the compositions of the present invention. The amount of pigment may vary over a wide range. Preferably, it is present in an amount of about 0.1-5 wt-%.
The compositions of the present invention can also include preservatives, 25 such as bacteriostatic agents, antimicrobial agents such as hexahydro- 1 ,3,5-tris(2-hydroxyethyl)-s-triazine, antifungal agents, and the like. Preferably, a preservative is used in an amount of about 0.01-0.2 wt-%.
Although the compositions of the present invention are water-based compositions, they can also include minor amounts of organic solvents. For example, 30 they can include solvents that act as film enhancers, i.e., that improve the flowability of polymer emulsion particles such that the emulsion more readily forms a film.
Suitable such film enhancers include ester alcohols and glycol ethers. Preferably, a 212~753 -film enhancer is present in an amount effective to impart advantageous film-forming characteristics to the compositions of the present invention. More preferably, a film enhancer is present in an amount of about 0.1-1.0 wt-%.
The compositions of the present invention can also include additional 5 corrosion inhibitors, such as phosphates, metaborates, sulfonates, silica, and the like.
A corrosion inhibitor may be present in the compositions of the present invention to perform other functions. For example, a corrosion inhibitor such as zinc phosphate can also be used as a filler. Typically, if used a corrosion inhibitor is present in an amount of about 5-20 wt-%.
The compositions of the present invention can also include additives for adjusting or stabilizing the pH. Suitable such compounds include any pH adjusting or stabilizing agent used in latex emulsion paints, such as 2-amino-2-methyl- 1-propanol or ammonia. Preferably, a pH adjusting additive is present in an amount effective to adjust the pH of the composition to about 8-10, and more preferably 15 about 9-9.5. Typically, for the compositions of the present invention, this required about 0.05-0.15 wt-%.
The compositions of the present invention can also include additives that reduce the freezing point of the composition, i.e., antifreeze. Suitable such compounds include any antifreeze used in latex emulsion paints. Examples of suitable 20 antifreezes include, but are not lirnited to, ethylene glycol and propylene glycol.
Preferably, an antifreeze is present in an amount effective to adjust the freezing point of the composition to a temperature below that which it would normally encounter in manufacture, transportation, or application. Typically, this is about 32F (0C).
Thus, for the compositions of the present invention, this requires up to about 2 wt-25 %, preferably about 0.05-1.5 wt-~o.
The compositions of the present invention are made by mixing the ingredients until a uniformly dispersed mixture is obtained. Any conventional mixing techniques can be used. The compositions are storage stable. That is, they can be stored for up to about 60-90 days at 60-80F ( I 5.6-26.7C) without significant 30 separation or agglomeration of the components. They can be applied to a surface using any conventional coating technique, such as spray coating or brushing, for example. The technique used is typically determined by the viscosity of the particular 212~75~ -composition. That is, the compositions having a lower viscosity, i.e., a viscosity of less than about 50,000 Centipoise, can generally be spray coated.
Experimental Examples The following examples are offered to further illustrate the various specific and preferred embodiments and techniques. It should be understood, however, that many variations and modifications may be made while remaining within the scope of the present invention.
Specific examples of formulations within the scope of the present invention are included within the following table. The preparation and properties of these formulations follow.
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- - 212~53 Example 1 Preparation and Properties of Formulation A
Preparation A water-based coating was prepared by placing water (51.0 gm, 10.1%), 5 into a plastic container. This was then placed under an air mixer (1/4 inch motor) and the following components were added with mixing using a 2 inch spindle at low speed: 50% solution of potassium tripolyphosphate in water (2.0 gm, 0.4%), whichis available from FMC Corporation, Industrial Chemical Group (Philadelphia, PA);ethylene glycol (5.5 gm, 1.1 %) which is available from Ashland Chemicals 10 (Columbus, Ohio); Colloid 646 emulsifiable liquid foam control agent (1.0 gm, 0.2%) which is available from Colloids, Inc. (Newark, NJ); Tamol~ 983 organic polyaciddispersant (5.5 gm, 1.1 %), which is available from Rohm and Haas Company (Philadelphia, PA); AMP-95TM (2-amino-2-methyl-1-propanol) with 5% water (0.5 gm, 0.1%), which is available from Angus Chernical Company; Tint-Ayd(~ WD 2345 15 pigment dispersion (4.5 gm, 0.9%), which is available from Daniel Products Company (Jersey City, NJ); 30% solution of Pluronic(~) F-87 block copolymer nonionic surfactant in water (5.0 gm, 1.0%), which is available from BASF Wyandotte Corporation, Performance Chemicals (Parsippany, NJ); Attagel(~) 40 mineral thickener (10.0 gm, 2.0%) (mixed in at high speed); Haloflex 202 vinylidene chloride/vinyl20 chloride/acrylic emulsion (69.0 gm, 13.8%), which is available from Zeneca Resins (Wilmington, MA); ArolonTM 870 (EA-6556) styrene-butadiene emulsion (137.5 gm, 27.5%); and TexanolTM ester-alcohol (2,2,4-trimethyl-1,3-pentanediol monoisobutyrate, 2.0 gm, 0.4%), which is available from Eastman Chemicals (Kingsport, TN).
Following this, Polymica 325 (103.0 gm, 20.6%), which is available from Mica Inc., 25 and ASP 400 aluminum silicate pigment filler (103.0 gm, 20.6%), which is avai lable from Engelhard (Edison, NJ), were then added in small increments and the resultant mixture was mixed until smooth. Acrysol(~) TT-615 acrylate thickener (0.5 gm, 0.1%) was premixed with water (0.5 gm, 0.1%) and then added to this mixture. This final composition was mixed until smooth (solids content = 67%). This composition is 30 particularly adapted for a chip-resistant, corrosion-resistant coating over a primed or topcoated surface that can be either baked or air-dried.
212~7~3 ls Viscosity The viscosity of this composition at 20C was determined to be 12,000-15,000 Centipoise on a Brookfield viscometer (BH-type, rotor No. 7 rotation frequency = 20 rpm). The viscosity of an aged sample of the composition at 20C
was determined to be 16,000-20,000 Centipoise. The composition was aged by placing a sealed container containing the sample in a thermostatic vessel adjusted to 40C for 10 days, and then at 20C for 20-24 hours.
Cold Bendin~ Resistance The composition was coated uniformly on an electrodeposited plate, i.e., a primed steel plate, obtained from Advanced Coating Technologies Inc. (ACT Inc.), Hillsdale, MI, to form a coating thickness of 50 mils (1.3 mm). The test plate was baked for 20 minutes in an dryer adjusted to 130C, held at room temperature for 2 hours, and then held at -30C for 3 hours. The test piece was then bent immediately at an angle of 180 uniformly along a mandrel of 25 mm diameter in a period of about 5 seconds, with the coated surface of the test piece facing outward. There was no cracking, chipping, or peeling observed.
Salt Spray Test A 100 mm long knife cut was placed in an electrodeposited plate down the steel plate base. The composition was coated uniformly on half of the plate such that half of the line was uncoated. The coating thickness was 50 mils (1.3 mm).
The test plate was baked for 20 minutes in an dryer adjusted to 130C, cooled toroom temperature, and then placed in a 35C salt spray tester at an angle of 70 from horizontal for 10 days. The coating was then removed from the test piece by scraping it away. There was no corrosion or undercut observed.
Chip Resistance The composition was coated uniformly on an electrodeposited plate to form a coating thickness of 40 mils (1.0 mm). The test plate was held at 20C and 65% relative humidity for 30-60 minutes, baked for 20 minutes in an air-stirringthermostatic vessel adjusted to 130C, then held at 20C and 65% relative humidity 21287~3 for 24 hours, and ~Inally held at room temperature for 24 hours. Two knife cuts were made in the coating in a cross-cut pattern such that the coating was cut through to the steel base plate. The coated test piece was placed in a testing apparatus at an angle of 60 from horizontal with a funnel (20 mm inside diameter, 2000 mm overall 5 length) placed 5-10 mm above the surface of the test piece. Nuts previously dropped on a sample paper board 700 times were dropped onto the center of cross-cut in coating through the funnel. The total mass of nuts (42 kg) did not abrade the coating.
A second test piece was prepared in a manner analogous to the first test 10 piece, but with the additional treatment steps of holding the test piece for 4 days in a thermostatic water bath at 40C and cooling to room temperature prior to making the cross cut in the coating. The test piece was subjected to the same procedure as described above within 2-5 hours of taking it out of the water bath. After 35 kg of nuts, the coating started showing failure.
A third test piece was prepared in a manner analogous to the second test piece, but with the test piece held for 10 days in a thermostatic water bath at 40C.
The test piece was subjected to the same procedure as described above within 2-5hours of taking it out of the water bath. After 28 kg of nuts, the coating started showing failure.
Water Spray Test (wash off resistance) A 40 mil ( 1.0 mm) coating of the composition was applied to the underside of an automobile and allowed to air dry for 3-3.5 hours. The automobile was then placed in a water chamber where water was sprayed from the top and 25 bottom to detect leaks. This coating passed this test.
Bakin~ Test A 30 mil (0.8 mm) coating of the composition was applied to the underside of an automobile and allowed to air dry for 70 minutes. The automobile30 was then baked at 265F (130C) for 20 minutes. No blistering was observed.
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Example 2 Preparation and Properties of Formulation B
Preparation A water-based coating was prepared by placing water (52.0 gm, 5.2%) into a plastic container. This was placed on an air mixer (1/4 inch motor) and the following components were added with mixing using a 2 inch spindle at low speed after each addition: 50% solution of potassium tripolyphosphate in water (4.2 gm, 0.4%); Tamol(~) 983 polyacid dispersant (9.2 gm, 0.9%); Tint-Ayd(~) WD 2345 pigment dispersion (9.2 gm~ 0.9%); and ColloidTM 646 emulsifiable liguid foam control agent (0.5 gm, 0.1%). The following components were added to this mixture with mixing at medium speed: Daratak(~) 3631 vinylidene chloride based adhesive emulsion (104.1 gm, 10.4%), which is available from W.R. Grace & Co. Orgarlic Chemicals Division (Lexington, MA); AMP-~STM (2-amino-2-methyl-1-propanol with 5% water, 1.0 gm, 0.1%); and ArolonTM 870 (EA-6556) styrene-butadiene emulsion (174.9 gm, 17.5%). To this mixture was added DualiteTM M6017AE-04 hollow composite microsphere filler (18.4 gm, 1.8%), which is available from Pierce &
Stevens Corp. (Buffalo, NY). Snowhite 20 calcium/magnesium carbonate (312.3 gm.
31.2%), which is available from Steep Rock Resources Inc. (Pickering, Ontario, Canada), was then added in small increments, followed by sodium potassium alumina silicate (312.3 gm, 31.2%) in small increments and the resultant mixture was mixed until smooth. Finally, the following components were added in order, with mixing:
OnyxideTM-200 preservative (hexahydro-],3,5-tris(2-hydroxyethyl)-s-triazine, 0.5 gm, 0.1%), which is available to Metal Working Chemicals & Equipment Co., Inc. (LakePlacid, NY); TexanolTM ester-alcohol (2,2,4-trimethyl-1,3-pentanediol monoisobutyrate, 1.3 gm, 0.1%); and Acrysol(~ TT-615 acrylate thickener (0.5 gm, 0.1%). This final composition was mixed until smooth (solids content = 80%). This composition is particularly adapted for a chip-resistant, sound-deadening, corrosion-resistant coating that can be air-dried.
2I287~
Viscosity The viscosity of this composition at 20C was determined to be 10-30 seconds (about 20,000-60,000 Centipoise) on a Sever viscometer using test method5 SAE J1524, 3.175 mm orifice, 69 kPa pressure, 50 gm sample weight).
Cold Impact Resistance The composition was coated uniformly on an electrocoated plate, i.e., a primed steel plate, obtained from ACT, Inc. to form a coating thickness of 20 mils 10 (0.5 mm). The test plate was air dried vertically for a period of 24 hours, held for 14 days at 70C, followed by at least 4 hours at -23C. The test piece was then subjected to two 1.7 J impacts. There was no cracking or peeling observed.
Salt Spray Test The composition was coated uniformly on an electrocoated plate to form a coating thickness of 20 mils (0.5 mm). The test plate was air dried vertically for a period of 72 hours, and then placed in a 38C salt spray tester for 14 days. The coating was then removed from the test piece by solvent cleaning. There was no corrosion or undercut observed.
Chip Resistance The composition was coated uniformly on an electrocoated plate to form a coating having a thickness of 20 mils (0.5 mm). The test plate was air dried for 72 hours. These panels were then left in a freeær at -10F (-23.3C) for 4 hours, 25 placed in a gravelometer, and shot with 5 pints of gravel immediately. There was no chipping or any other film failures.
Example 3 Preparation and Properties of Formulation C
Preparation A water-based coating was prepared by placing water (126.5 gm, 12.6%) into a plastic container. This was placed on an air mixer and BentoneTM LT
organoclay (0.5 gm, 0.1%) was added with mixing at a moderate speed until smoothor until particles were dispersed. The following components were then added withmixing: Foamaster(~) S defoamer (1.1 gm, 0.1%); 30% solution of Pluronic(~ F-87 block copolymer surfactant in water (11.0 gm solution, 1.1%); and Tint-Ayd(~) WD2345 pigment dispersion (8.9 gm, 0.9%). Zinc phosphate (111.0 gm, 11.1%) was then added and the composition was mixed until smooth. ArolonTM 870 (EA-6556) styrene-butadiene emulsion (407.8 gm, 40.8%) was then added with mixing. To thismixture was added TechFilTM C117 talc (333.0 gm, 33.3%), which is available fromLuzenac (Oakville, Ontario, Canada). This final composition was mixed until smooth (solids content = 65%). This composition is particularly adapted for a room-temperature sprayable corrosion-resistant coating that can be air-dried.
Viscosity The viscosity of this composition at 25C was determined to be 2500-5000 Centipoise on a Brookfield viscometer (spindle No. 5 rotation frequency = 20 rpm).
Salt Spray Test Clean cold rolled steel panels were coated with the composition at a thickness of 8-10 mils (0.2-0.25 mm) wet and air dried for 72 hours. The panels were then scribe marked and placed in a salt fog chamber (5% sodium chloride solution is sprayed) for 168 hours. No corrosion or undercutting was noted at the completion of the test.
2l~87s3 Chip Resistance The composition was coated uniformly on an electrocoated plate to form a coating having a thickness of 20 mils (0.5 mm). The test plate was air dried for 72 hours. These panels were then tested according to SAE J400 test method, left in 5 a freezer at -10F (-23.3C) for 4 hours, placed in a gravelometer, and shot with 5 pints of gravel immediately. There was no chipping or any other film failures.
Example 4 Prel)aration and Properties of Formulation D
10 Preparation A water-based coating was prepared by placing water (5.1 gm, 10.2%) into a plastic container and a 50% solution of potassium tripolyphosphate in water (2.6 gm, 0.5%) was added. This was placed on an air mixer (1/4 inch air motor) and mixing was started using a 2 inch spindle at low speed. Ethylene glycol was 15 then added (5.5 gm, 1.1%). Attagel~) 40 thickener (10.2 gm, 2.0%) was then added and the mixing speed was increased to medium. This composition was mixed for 10 minutes. The following components were added in order and the composition was then mixed at moderate speed: Tamol~) 983 polyacid dispersant (5.45 gm, 1.1%);
ColloidTM 646 emulsifiable liquid foam control agent (4.09 gm, 0.8%); and Tint-20 Ayd(~) WD 2345 pigment dispersion (5.45 gm, 1.1%). The following componentswere added in order and the composition was then mixed at moderate speed:
ArolonTM 870 (EA-6556) styrene-butadiene emulsion (136.4 gm, 27.3%); AMP-95TM
(2-amino-2-methyl-1-propanol with 5% water, 0.7 gm, 0.1%); and Haloflex 202 vinylidene chloride emulsion (68.2 gm, 13.6%). Aluminum silicate pigment ASPTM
25 400 filler (102.3 gm, 20.5%) was then added in small increments with mixing.
Polymica 325 filler (102.3 gm, 20.5%) was then added in small increments and thecomposition was mixed until smooth. The following components were then added in order with mixing: OnyxideTM-200 preservative (hexahydro-1,3,5-tris(2-hydroxyethyl)-s-triazine, 0.3 gm, 0.1%) and TexanolTM ester-alcohol (2,2,4-trimethyl-1,3-pentanediol 30 monoisobutyrate, 2.7 gm, 0.5%). Acrysol~ TT-615 acrylate thickener (1.4 gm, 0.3%) was premixed with water (1.4 gm, 0.3%) and then added to this mixture. This final composition was mixed until smooth (solids content = 66%). This composition is 21~7~3 particularly adapted for a chip-resistant, corrosion-resistant coating over a primed or topcoated surface that can be either baked or air-dried.
Viscosity The viscosity of this composition at 20C was determined to be 15,000 Centipoise on a Brookfield viscometer (BH-type, rotor No. 6 rotation frequency = 20 rpm). The viscosity of an aged sample of the composition at 20C was determined to be about 15,000-20,000 Centipoise. The composition was aged by placing a sealed container containin~ the sample in a thermostatic vessel adjusted to 50C for 10 days, and then at 20C for 20-24 hours. The viscosity of a sample subjected to freezing and thawing of the composition at 20C was determined to be 20,000 Centipoise.
The composition was subjected to a freezing-thawing cycle three times (-5C for 16 hours and 20C for 8 hours) by placing a sealed container containing the sample in a thermostatic vessel adjusted, and finally at 20C for 20-24 hours.
Cold Bendin~ Resistance The composition was coated uniformly on a terne steel sheet, i.e., a substrate used to make automobile gas tanks, to form a dry coating thickness of 12 mils (0.3 mm). The test plate was baked for 5 minutes at 80C and then for 15 minutes in an dryer adjusted to 120C. Finally the test sample was held at room temperature for 24 hours, and then held at -30C for 3 hours. The test piece wasthen bent immediately at an angle of 180 uniformly along a mandrel of 25 mm diameter in a period of about 5 seconds, with the coated surface of the test piece facing outward. There was no peeling observed.
Salt Spray Test Two terne sheets were welded together and coated uniformly such that the coating thickness was 12 mils (0.3 mm). The test plate was baked for 5 minutes at 80C and then for 15 rninutes in an dryer adjusted to 120C, then cooled to room temperature over a 24 hour period. The test piece was then placed in a 38C saltspray tester at an angle of 70 from horizontal for 42 days. The test procedure carried out was ASTM B117. After 42 days, the test piece was removed and the 212~753 -coating was cleaned off within I hour. There was little or no corrosion or undercut observed.
Bakin~ Test 5A 50 mil (1.3 mm) coating of the composition was applied to a terne sheet panel. The panel was then baked at 176F (80C) for 5 minutes, and then at248F (120C) for 15 minutes. No blistering was observed. Furthermore, the coating displayed excellent adhesion and chipping resistance.
10Chip Resistance The composition was coated uniformly on a terne sheet to form a coating thickness of 12 mils (0.3 mm). The test plate was baked for 5 minutes at 80C and then for 15 minutes at 120C, and finally held at room temperature for 24 hours.The coated test piece was placed in a testing apparatus at an angle of 60 from 15horizontal with a funnel (20 mm inside diameter, 2000 mm overall length) placed 5-10 mm above the surface of the test piece. Brass nuts previously dropped on a sample paper board 700 times were dropped onto the center of cross-cut in coating through the funnel. The total mass of nuts needed to abrade the coating was 27 kg.
A second test piece was prepared in a manner analogous to the first test 20piece, but with the additional treatment steps of holding the test piece for 10 days in a thermostatic water bath at 40C. The test piece was subjected to the same procedure as described above within 2-5 hours of taking it out of the water bath.
The total mass of nuts needed to abrade the coating was 21 kg.
Examples 5-7 Preparation and Properties of Formulations E, F, & G
Preparation Each water-based coating was prepared by placing water (75.0 gm, 3010.4%) into a plastic container and a 50% solution of potassium tripolyphosphate in water (3.8 gm, 0.5%) was added. This was placed on an air mixer (1/4 inch air motor) and mixing was started using a 2 inch spindle at low speed. Ethylene glycol was then added (8.0 gm, 1.1%). Attagel(~) 40 thickener (15.0 gm, 2.1%) was then added and the mixing speed was increased to medium. Each composition was mixed for 10 minutes. The following components were added in order to each compositionand then mixed at moderate speed: ColloidTM 646 emulsifiable liquid foam control5 agent (4.0 gm, 0.6%); and Tint-Ayd(~ WD 2345 pigment dispersion (8.0 gm, 1.1%).
The following components were added in order to each composition and then mixed at moderate speed: ArolonTM 870 (EA-6556) styrene-butadiene emulsion (300.0 gm, 41.5%); and AMP-95TM (2-arnino-2-methyl-1-propanol with 5% water, 1.0 gm, 0.1%).Either Kaopaque 10 del~min~t~d aluminum silicates (300.0 gm, 41.5%, Composition 10 E), which is available from Georgia Kaolin (Union, NJ), SER-X hydrous aluminasilica (300.0 gm, 41.5%, Composition F), or Polymica 325 mica (300.0 gm, 41.5%, Composition G) was then added in small increments to each composition and then mixed until smooth. The following components were then added to each compositionin order, with mixing: OnyxideTM-200 preservative (hexahydro- 1,3,5-tris(2-15 hydroxyethyl)-s-triazine, 0.5 gm, 0.1%) and TexanolTM ester-alcohol (2,2,4-trimethyl-1,3-pentanediol monoisobutyrate, 4.0 gm, 0.6%). Acrysol(~) TT-615 acrylate thickener (1.0 gm, 0.1%) was prernixed with water (2.0 gm, 0.3%) and then added to each mixture. This final compositions were mixed until smooth (solids content = 66%).These compositions are particularly adapted for a chip-resistant, 20 corrosion-resistant, sound-deadening coatings over a primed or topcoated surface.
Composition E containing Kaopaque 10 del~min~ted aluminum silicates is particularly well adapted for baking a wet coating, i.e., a coating that has not been previously air dried, at a high film thickness without blistering.
Viscosity Using a Severs viscometer (parameters: 0.125 inch orifice, 10 psi, 50 gm), the viscosities of these compositions at 20C were determined to be: 40 seconds (90,000 Centipoise) for Composition E; 32 seconds (50,000 Centipoise) for 30 Composition F; and 46 seconds (80,000 Centipoise) for Composition G.
212~7~3 _ Bakin~ Test A 50 mil (1.3 mm) coating of each composition was applied to a terne coat panel. The panel was then baked at 266F (130C) for 20 minutes. All coatings displayed excellent adhesion. The coating prepared from Composition E displayed 5 no blisters. The coating prepared from Composition F displayed a few very small blisters.
Chip Resistance The composition was coated uniformly on an electrocoated plate to form 10 a coating thickness of 20 mils (0.5 mm). The test plate was air dried for 30 minutes, then baked at 130C for 20 minutes. The coated test piece was placed in a testing apparatus at an angle of 60 from horizontal with a funnel (20 mm inside diameter, 2000 mm overall length) placed 5 mm above the surface of the test piece. Brass nuts were dropped through the funnel onto the center of a cross cut in the coating. The 15 total mass of nuts needed to abrade the coating was 56 kg. This test was repeated on another test plate after 11 days of soaking in water, with 42 kg of nuts needed to abrade the surface.
All percentages used herein are weight percents unless otherwise noted.
The complete disclosure of all patents, patent documents, and publications cited herein 20 are incorporated by reference. The foregoing detailed description and examples have been given for clarity of understanding only. No unnecessary limitations are to be understood therefrom. The invention is not limited to the exact details shown and described, for variations obvious to one skilled in the art will be included within the invention defined by the claims.
- Field of the Invention - The present invention provides a water-based coating composition for 5 metal substrates, such as steel surfaces. Specifically, the present invention provides a water-based coating composition that provides resistance to abrasion, e.g., chipping or cracking, and preferably resistance to environmental attack, e.g., corrosion.
Back~round of the Invention Various coating compositions for metal substrates, such as steel surfaces, are commercially available. These include, for example, oil-based red lead primers, zinc chromate-based alkyd primers, inorganic zinc-rich primers, organic zinc-rich primers, aluminized epoxy mastics, coal tar mastics, and asphalt- or petroleum-based resins. These coating compositions typically include organic solvents; however, it is generally desirable to use aqueous formulations in place of organic solvent formulations. Organic solvent formulations use expensive and toxic fl~mm~'~ le solvents, which must be captured upon drying the formulation to prevent air pollution.
The use of organic solvents usually generates higher costs and requires suitableexplosion-proof handling and exhaust systems. Furthermore, volatile organic solvents can pose health and safety problems.
Several aqueous-based, i.e., water-based, coating compositions for metal surfaces are known. For example, Trousil (U.S. Patent No. 4,282,131, issued August 4, 1981) discloses a water-based undercoating composition containing a butadiene-styrene latex emulsion. However, this coating composition will not adhere to painted substrates. Furthermore, it cannot be baked without previously air drying, which is often desirable in automobile applications. Generally, most water-based coatings that are baked, without being previously air dried, blister. This is particularly true if a thick coating is desired, i.e., greater than about 20 mils (0.5 mm) on a wet coating basis.
Most commercially available products, whether solvent-based or water-based, serve essentially as a primer or an undercoat for corrosion resistance to which a later paint layer is applied. They do not necessarily provide sound-proofing, nor are they typically resistant to abrasion, e.g., chipping or cracking. Once many of the 2I287~3 commercially available coatings are cut or chipped and the underlying steel surface is exposed, oxidation can occur, which can lead to further "undercutting" of thecoating. That is, the rusting process can begin at the exposed surface and spread such that the rusting process proceeds beneath the coating. Thus, many commercially S available coating compositions cannot be used in environments where the coating is subject to impact or abrasion, particularly if corrosion resistance is desired.
Summary of the Invention The present invention provides a water-based coating composition for metal substrates, such as steel surfaces, that provides resistance to abrasion. It can be used wherever a hard, durable, abrasion resistant coating is needed. It is particularly useful for coating vehicles or vehicle parts, such as the underbodies of cars. It can also be used in coating appliances or other pieces of metal furniture.
Advantageously, preferred embodiments of the water-based coating composition canprovide corrosion resistance and/or sound deadening characteristics. Particularly preferred embodiments of the water-based coating composition can be baked at a temperature of about 200-300F (93-149C) at high film thicknesses, i.e., at least about 20 mils (0.5 mm) on a wet coating basis, with little or no prelirninary air drying. Advantageously, such baked coatings exhibit little or no blistering.
In its broadest sense, the water-based coating composition of the present invention includes a styrene-butadiene emulsion, an effective amount of a filler, and an effective amount of a thickener. As used herein, "an effective amount" is an amount capable of producing a composition having a viscosity of at least about 3000 Centipoisem under ambient conditions. Preferably, the viscosity is at least about 15,000 Centipoise and no greater than about 50,000 Centipoise, under ambient conditions. Particularly preferred embodiments of the invention include a water-based coating composition, and a coating prepared therefrom, that include about 10-50 wt-% styrene-butadiene emulsion, about 30-70 wt-% filler, and about 0.1-3 wt-%
thickener, wherein the water-based coating composition has a viscosity of at least about 3000 Centipoise, under ambient conditions, and a solids content of about 60-80 wt-%.
2l28753 -Also included within the scope of the invention is a method of treating a vehicle for resistance to environmental attack. -This method includes coating the underbody of the vehicle with a water-based coating composition as described above and curing the coating. The composition preferably includes about 10-50 wt-%
styrene-butadiene emulsion, about 30-70 wt-% filler, about 0.1-3 wt-% thickener,about 0.05-1 wt-% defoaming agent, and about 0.1-2 wt-% dispersant. This preferred water-based coating composition has a viscosity of at least about 15,000 Centipoise and a solids content of about 60-80 wt-%. Although the coating composition can be cured upon air drying for 72 hours or more, preferably, and advantageously, it can be cured upon baking the composition at a temperature of about 200-300F (93-149C).
Detailed Description of the Invention The present invention provides a water-based coating composition that can be used wherever a hard, durable, abrasion-resistant, i.e., chip-resistant, coating is needed. For example, it can be used in coating automobile parts, particularly the underbodies of cars, trucks, etc. It can also be used in coating appliances or other pieces of metal furniture. Advantageously, preferred embodiments of the water-based coating composition can additionally provide corrosion resistance and/or sound deadening characteristics. Generally, a good chip-resistant and corrosion-resistant coating composition should be one that forms a coating that is resistant to chipping, cracking, or cutting, and is resistant to moisture. Advantageously and preferably the composition should also have a relatively high solids content, i.e., greater than about 70 wt-%, to provide additional insulation from noise.
The water-based coating composition of the present invention includes a unique combination of a styrene-butadiene (SBR) emulsion, a filler, and a thickener.
The ratio of SBR:filler:thickener can be adjusted to produce a composition having an appropriate viscosity such that a dry coating of at least about 15 mils (0.4 mm) or a wet coating of at least about 20 mils (0.5 mm) can be produced. Typically, these components are used in amounts effective to produce a composition having a viscosity of at least about 3000 Centipoise, under ambient conditions. Preferably, these components are used in amounts effective to produce a composition having a viscosity 2I ~875~
of at least about 15,000 Centipoise, and more preferably no greater than about 50,000 Centipoise~ under ambient conditions. As used in this context, ambient conditions refers to atmospheric pressure and a temperature of about 20-30C (i.e., room temperature).
5The solids content of the compositions of the present invention are typically and preferably about 60-80 wt-%. For formation of a coating with advantageous corrosion resistance and antichip characteristics, the solids content need only be about 60-70 wt-%; however, if a composition is also to impart sound deadenin~ characteristics to a coating as well, the composition preferably has a solids 10content of about 70-80 wt-%. The filler contributes significantly to the solids content of the compositions. Optional components, such as a pigment, can also contribute to the solids content of the composition.
As used herein, a corrosion-resistant coating is one that withstands a salt spray test as described by ASTM B117 (American Society of Testing and Materials,151985) for at least about 168 hours. By this it is meant that a steel workpiece with a coating of the present invention exhibits substantially no corrosion or undercutting within a 168-hour period on cold rolled steel or a 500-hour period on primed steel.
Preferably, the corrosion-resistant coating of the present invention withstands the ASTM B117 salt spray test for at least about 300 hours on cold rolled steel, and20more preferably for at least about 500 hours on cold rolled steel.
As used herein, a chip-resistant coating, i.e., an antichip coating, is one that withstands a chip test as described by SAE J400 (Society of Automotive Engineers, June, 1980) with a rating of no less than about 5 on a scale of 1-10. By this it is meant that a steel workpiece with a coating of the present invention does 25not substantially chip the coating and expose the bare metal. Preferably, the chip-resistant coating of the present invention has a rating of no less than about 7, and more preferably, no less than about 9, according to this test procedure.
As used herein, a sound-deadening coating is one that has a sound decay of at least about 11 db/sec according to a Geiger Plate test as described by the30Method of Geiger & Hamme of Ann Arbor, MI. Preferably, the sound-deadening coating of the present invention has a sound decay of at least about 20 db/sec, and 212~7~3 more preferably, a sound decay of at least about 30 db/sec, according to this test .procedure. - - -Generally, water-based coatings are air dried. However, in certain applications, such as in the automotive industry it is advantageous to be able to bake S the coating. Typically, water-based coatings having a thickness of about 20 mils (0.5 mm) wet, or more, cannot be baked without first being air dried or flashed. Thisis problematic at least because of the time involved in the air drying.
Advantageously, preferred compositions of the present invention can be baked at a temperature of about 200-300F (93-149C) substantially immediately, i.e., within 10 about 1 hour of applying the coating, without causing blisters. That is, with little or no air drying, preferred compositions of the present invention can be baked without detrimentally affecting the integrity of the coating.
Generally, water-based underbody coating compositions are applied after the workpiece, i.e., automobile, is primed and painted. Therefore, the compositions 15 must adhere to the paint. Generally, however, conventional water-based coating compositions do not adhere well to paint (base coat and/or clear coat) in cold conditions. Furthermore, typical conventional water-based coating compositions cannot be applied under the paint and withstand the baking step of the primer and painting operation. Advantageously, preferred water-based coating compositions of the present 20 invention can be applied under paint and withstand baking temperatures. Other water-based coating compositions of the present invention can be applied over paint with good adhesion. Typically, these compositions are air dried. Some compositions ofthe present invention can be applied either under or over paint.
25 Styrene-Butadiene Emulsion The major component of the composition of the present invention is a styrene-butadiene (SBR) emulsion, i.e., a copolymer of styrene and 1,3-butadiene.
The SBR emulsion is the major binder and film former of the composition. It is responsible for imparting flexibility to the coating composition as well as resistance 30 to abrasion, e.g., chipping. Suitable SBR emulsions are those that have a bound styrene content of about 60%. Such emulsions are comrnercially available.
21~75~
.
Examples of suitable SBR emulsions Include, but are not limited to:
ArolonTM 870 (EA-6556) styrene-butadiene emulsion available from Reichhold Chemicals, Inc. (Research Triangle Park, NC); Styrofan ND 593 carboxylated styrene-butadiene dispersion available from BASF Corporation (Chattanooga, TN); and Good-5 Rite Latex No. 1800-X-73 available from B.F. Goodrich Company (Akron, Ohio).
Preferably, the compositions of the present invention include ArolonTM 870 (EA-6556) styrene-butadiene emulsion.
Generally, the SBR emulsion is present in an amount effective to impart desirable properties to the composition. In preferred compositions, the styrene-10 butadiene emulsion is present in an amount of about 10-50 wt-%, and more preferably in an amount of about 15-45 wt%.
Fillers The solids content of the composition is primarily the result of a filler.
15 The filler also contributes to improved chipping resistance and sound barrierproperties. Preferred fillers also contribute to corrosion protection. Suitable fillers include, but are not limited to calcium/magnesium carbonates, calcium carbonates, aluminum silicates, talc (i.e., magnesium silicates), mica (i.e., a variety of silicates), barytes (barium sulfate), clay (i.e., aluminum silicates), sodium potassium alumina 20 silicate, and metal phosphates such as zinc phosphate.
A combination of various fillers can be used in the water-based coating compositions of the present invention to impart a variety of properties to the coatings.
For example, when a coating with a high level of chipping resistance is desired, the composition preferably includes a combination of calcium/magnesium carbonate and25 talc. When a coating with a high level of corrosion protection is desired, the composition preferably includes a combination of a metal phosphate, e.g., zinc phosphate, and mica or talc. When a coating with a high level of sound deadeningis desired, the composition preferably includes a combination of any of the following fillers: calcium/magnesium carbonates, calcium carbonate, talc, mica, or barytes.
30 In the most preferred compositions of the present invention, however, the filler is a non-mica containing filler.
212875~
-In preferred compositions, the filler is present in an amount of at least about 25 wt-%. More preferably, the filler is present in an amount of about 25-70 wt-%. For applications in which the composition is baked to form a cured coating, the filler is preferably present in an amount of about 25-50 wt-%. Generally, the 5 lower the solids content the longer the baking time required for complete cure of the composition. For applications in which the composition is air dried to form a cured coating, the filler is preferably present in an amount of about 30-70 wt-%.
Thickeners The compositions of the present invention also include an effective amount of a thickener. The thickener is used to build flow resistance, viscosity, and gel characteristics. Generally, a composition with optimal gel characteristics produces a more consistent and uniform coating, i.e., one that does not easily run or sag.
Suitable thickeners include clay, magnesium/aluminum silicates, acrylates, xanthum 15 gum, and the like. Examples include, but are not limited to, Acrysol(~ TT-6 15 acrylic polymer emulsion available from Rohm and Haas Company (Philadelphia, PA), Attagel(~) mineral thickener (hydrated magnesium aluminum silicate) available from Engelhard Corporation (Edison, NJ), BentoneTM LT organoclay thickener available from NL Chemicals, Inc. (Hightstown, NJ). Preferably, the compositions of the 20 present invention include an acrylate thickener, a magnesiumlaluminum silicate thickener, or clay. More preferably, they include an acrylate thickener such as Acrysol~ TT-615 acrylic polymer emulsion at least because it provides excellent gel characteristics. Most preferably, certain compositions of the present invention include a combination of an acrylate thickener, such as Acrysol(~ TT-615 acrylic polymer25 emulsion, and a magnesium/aluminum silicate thickener, such as Attagel(~) mineral thickener.
In preferred water-based coating compositions of the present invention, the thickener is present in an amount of at least about 0.1 wt-%. More preferably, the thickener is present in an amount of no more than about 3 wt-%. For 30 applications in which the composition is baked to form a cured coating, the thickener is present in an amount sufficient to produce high gel characteristics such that a coating with a textured finish is formed when spray applied. A textured finish has ~2~753 -a higher surface area and releases water faster in a baking process. Generally, for baking applications, the thickener is preferably present in an amount-of about 2-3 wt-%. For applications in which the composition is air dried to form a cured coating, the thickener is preferably present in an amount of about 0.1-1 wt-%. Generally, the 5 thicker a coating thickness desired, the more thickener is included in the composition.
Miscellaneous Components Various other optional ingredients can be added to the composition without affecting or altering the desired characteristics of the composition. Certain 10 ingredients can be added to improve various characteristics of the composition and resultant coating, such as corrosion resistance, for example. Such ingredients include, for example, secondary film formers, defoaming agents, dispersants, surfactants,pigments, preservatives, and pH adjusters.
It is to be understood that any individual component used in the 15 compositions of the present invention can be used to perform various functions. For example, as seen above, clay can be used as both a thickener and a filler. Pigments can be used as fillers and to merely impart color.
The compositions of the present invention include a styrene-butadiene emulsion as the primary film former and binder. Additional, i.e., secondary, film 20 formers can also be included in the composition to enhance the formation of auniform coating. Furthermore, components can be added to the composition to enhance adhesion properties. Certain secondary film formers can be added that enhance both film formation and adhesion properties. For example, the composition can include a vinylidene chloride emulsion, such as a vinylidene chloride/vinyl 25 chloride/aclylic emulsion, that is designed for use in compositions that do not have good adhesive properties. The water-based coating compositions of the present invention preferably include an amount of a secondary film former effective to enhance adhesion and corrosion protection. More preferably, a secondary film former is used in an amount of no more than about 15 wt-%. Most preferably, it is present 30 in an amount of about 1-15 wt-%.
- Defoaming agents are preferably used in the water-based coating compositions of the present invention to prevent, or reduce the amount of, foaming ~12~753 -g during formulation and application. Typical defoarning agents are well known in the water-based paint industry. The water-based coating compositions of the present invention preferably include an amount of a defoaming agent effective to keep the amount of foam produced during formulation to a low level such that it does not 5 adversely affect the perforrnance properties of the coatings of the present invention.
Preferably, the water-based coating compositions of the present invention include about 0.05-1 wt-% of a defoaming agent.
Dispersants and surfactants can be used in the compositions of the present invention to assist in the dispersion of fillers, pigments, emulsions, etc.
10 Suitable dispersants and surfactants include inorganic polyphosphates such as potassium tripolyphosphate (K5P30,o), organic polyacids, and nonionic difunctional block copolymers. Preferably, a dispersant or surfactant is used in an amount effective to provide good wetting of the solids so that a homogeneously dispersed composition is formed that can be generally evenly applied to surfaces at a variety 15 of thicknesses. More preferably, a dispersant or surfactant is used in an amount of about 0.1-2 wt-%, and most preferably in an amount of about 1 wt-%.
A pigment can also be used in the compositions of the present invention to provide color. As discussed above, pigments can also be used to increase the solids content of the compositions and perform the function of a filler, for example.
20 Preferably, the pigment is black as the compositions are typically used for undercoating automobiles. Generally any inorganic or organic pigment can be used in the compositions of the present invention. The amount of pigment may vary over a wide range. Preferably, it is present in an amount of about 0.1-5 wt-%.
The compositions of the present invention can also include preservatives, 25 such as bacteriostatic agents, antimicrobial agents such as hexahydro- 1 ,3,5-tris(2-hydroxyethyl)-s-triazine, antifungal agents, and the like. Preferably, a preservative is used in an amount of about 0.01-0.2 wt-%.
Although the compositions of the present invention are water-based compositions, they can also include minor amounts of organic solvents. For example, 30 they can include solvents that act as film enhancers, i.e., that improve the flowability of polymer emulsion particles such that the emulsion more readily forms a film.
Suitable such film enhancers include ester alcohols and glycol ethers. Preferably, a 212~753 -film enhancer is present in an amount effective to impart advantageous film-forming characteristics to the compositions of the present invention. More preferably, a film enhancer is present in an amount of about 0.1-1.0 wt-%.
The compositions of the present invention can also include additional 5 corrosion inhibitors, such as phosphates, metaborates, sulfonates, silica, and the like.
A corrosion inhibitor may be present in the compositions of the present invention to perform other functions. For example, a corrosion inhibitor such as zinc phosphate can also be used as a filler. Typically, if used a corrosion inhibitor is present in an amount of about 5-20 wt-%.
The compositions of the present invention can also include additives for adjusting or stabilizing the pH. Suitable such compounds include any pH adjusting or stabilizing agent used in latex emulsion paints, such as 2-amino-2-methyl- 1-propanol or ammonia. Preferably, a pH adjusting additive is present in an amount effective to adjust the pH of the composition to about 8-10, and more preferably 15 about 9-9.5. Typically, for the compositions of the present invention, this required about 0.05-0.15 wt-%.
The compositions of the present invention can also include additives that reduce the freezing point of the composition, i.e., antifreeze. Suitable such compounds include any antifreeze used in latex emulsion paints. Examples of suitable 20 antifreezes include, but are not lirnited to, ethylene glycol and propylene glycol.
Preferably, an antifreeze is present in an amount effective to adjust the freezing point of the composition to a temperature below that which it would normally encounter in manufacture, transportation, or application. Typically, this is about 32F (0C).
Thus, for the compositions of the present invention, this requires up to about 2 wt-25 %, preferably about 0.05-1.5 wt-~o.
The compositions of the present invention are made by mixing the ingredients until a uniformly dispersed mixture is obtained. Any conventional mixing techniques can be used. The compositions are storage stable. That is, they can be stored for up to about 60-90 days at 60-80F ( I 5.6-26.7C) without significant 30 separation or agglomeration of the components. They can be applied to a surface using any conventional coating technique, such as spray coating or brushing, for example. The technique used is typically determined by the viscosity of the particular 212~75~ -composition. That is, the compositions having a lower viscosity, i.e., a viscosity of less than about 50,000 Centipoise, can generally be spray coated.
Experimental Examples The following examples are offered to further illustrate the various specific and preferred embodiments and techniques. It should be understood, however, that many variations and modifications may be made while remaining within the scope of the present invention.
Specific examples of formulations within the scope of the present invention are included within the following table. The preparation and properties of these formulations follow.
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- - 212~53 Example 1 Preparation and Properties of Formulation A
Preparation A water-based coating was prepared by placing water (51.0 gm, 10.1%), 5 into a plastic container. This was then placed under an air mixer (1/4 inch motor) and the following components were added with mixing using a 2 inch spindle at low speed: 50% solution of potassium tripolyphosphate in water (2.0 gm, 0.4%), whichis available from FMC Corporation, Industrial Chemical Group (Philadelphia, PA);ethylene glycol (5.5 gm, 1.1 %) which is available from Ashland Chemicals 10 (Columbus, Ohio); Colloid 646 emulsifiable liquid foam control agent (1.0 gm, 0.2%) which is available from Colloids, Inc. (Newark, NJ); Tamol~ 983 organic polyaciddispersant (5.5 gm, 1.1 %), which is available from Rohm and Haas Company (Philadelphia, PA); AMP-95TM (2-amino-2-methyl-1-propanol) with 5% water (0.5 gm, 0.1%), which is available from Angus Chernical Company; Tint-Ayd(~ WD 2345 15 pigment dispersion (4.5 gm, 0.9%), which is available from Daniel Products Company (Jersey City, NJ); 30% solution of Pluronic(~) F-87 block copolymer nonionic surfactant in water (5.0 gm, 1.0%), which is available from BASF Wyandotte Corporation, Performance Chemicals (Parsippany, NJ); Attagel(~) 40 mineral thickener (10.0 gm, 2.0%) (mixed in at high speed); Haloflex 202 vinylidene chloride/vinyl20 chloride/acrylic emulsion (69.0 gm, 13.8%), which is available from Zeneca Resins (Wilmington, MA); ArolonTM 870 (EA-6556) styrene-butadiene emulsion (137.5 gm, 27.5%); and TexanolTM ester-alcohol (2,2,4-trimethyl-1,3-pentanediol monoisobutyrate, 2.0 gm, 0.4%), which is available from Eastman Chemicals (Kingsport, TN).
Following this, Polymica 325 (103.0 gm, 20.6%), which is available from Mica Inc., 25 and ASP 400 aluminum silicate pigment filler (103.0 gm, 20.6%), which is avai lable from Engelhard (Edison, NJ), were then added in small increments and the resultant mixture was mixed until smooth. Acrysol(~) TT-615 acrylate thickener (0.5 gm, 0.1%) was premixed with water (0.5 gm, 0.1%) and then added to this mixture. This final composition was mixed until smooth (solids content = 67%). This composition is 30 particularly adapted for a chip-resistant, corrosion-resistant coating over a primed or topcoated surface that can be either baked or air-dried.
212~7~3 ls Viscosity The viscosity of this composition at 20C was determined to be 12,000-15,000 Centipoise on a Brookfield viscometer (BH-type, rotor No. 7 rotation frequency = 20 rpm). The viscosity of an aged sample of the composition at 20C
was determined to be 16,000-20,000 Centipoise. The composition was aged by placing a sealed container containing the sample in a thermostatic vessel adjusted to 40C for 10 days, and then at 20C for 20-24 hours.
Cold Bendin~ Resistance The composition was coated uniformly on an electrodeposited plate, i.e., a primed steel plate, obtained from Advanced Coating Technologies Inc. (ACT Inc.), Hillsdale, MI, to form a coating thickness of 50 mils (1.3 mm). The test plate was baked for 20 minutes in an dryer adjusted to 130C, held at room temperature for 2 hours, and then held at -30C for 3 hours. The test piece was then bent immediately at an angle of 180 uniformly along a mandrel of 25 mm diameter in a period of about 5 seconds, with the coated surface of the test piece facing outward. There was no cracking, chipping, or peeling observed.
Salt Spray Test A 100 mm long knife cut was placed in an electrodeposited plate down the steel plate base. The composition was coated uniformly on half of the plate such that half of the line was uncoated. The coating thickness was 50 mils (1.3 mm).
The test plate was baked for 20 minutes in an dryer adjusted to 130C, cooled toroom temperature, and then placed in a 35C salt spray tester at an angle of 70 from horizontal for 10 days. The coating was then removed from the test piece by scraping it away. There was no corrosion or undercut observed.
Chip Resistance The composition was coated uniformly on an electrodeposited plate to form a coating thickness of 40 mils (1.0 mm). The test plate was held at 20C and 65% relative humidity for 30-60 minutes, baked for 20 minutes in an air-stirringthermostatic vessel adjusted to 130C, then held at 20C and 65% relative humidity 21287~3 for 24 hours, and ~Inally held at room temperature for 24 hours. Two knife cuts were made in the coating in a cross-cut pattern such that the coating was cut through to the steel base plate. The coated test piece was placed in a testing apparatus at an angle of 60 from horizontal with a funnel (20 mm inside diameter, 2000 mm overall 5 length) placed 5-10 mm above the surface of the test piece. Nuts previously dropped on a sample paper board 700 times were dropped onto the center of cross-cut in coating through the funnel. The total mass of nuts (42 kg) did not abrade the coating.
A second test piece was prepared in a manner analogous to the first test 10 piece, but with the additional treatment steps of holding the test piece for 4 days in a thermostatic water bath at 40C and cooling to room temperature prior to making the cross cut in the coating. The test piece was subjected to the same procedure as described above within 2-5 hours of taking it out of the water bath. After 35 kg of nuts, the coating started showing failure.
A third test piece was prepared in a manner analogous to the second test piece, but with the test piece held for 10 days in a thermostatic water bath at 40C.
The test piece was subjected to the same procedure as described above within 2-5hours of taking it out of the water bath. After 28 kg of nuts, the coating started showing failure.
Water Spray Test (wash off resistance) A 40 mil ( 1.0 mm) coating of the composition was applied to the underside of an automobile and allowed to air dry for 3-3.5 hours. The automobile was then placed in a water chamber where water was sprayed from the top and 25 bottom to detect leaks. This coating passed this test.
Bakin~ Test A 30 mil (0.8 mm) coating of the composition was applied to the underside of an automobile and allowed to air dry for 70 minutes. The automobile30 was then baked at 265F (130C) for 20 minutes. No blistering was observed.
21~875~
Example 2 Preparation and Properties of Formulation B
Preparation A water-based coating was prepared by placing water (52.0 gm, 5.2%) into a plastic container. This was placed on an air mixer (1/4 inch motor) and the following components were added with mixing using a 2 inch spindle at low speed after each addition: 50% solution of potassium tripolyphosphate in water (4.2 gm, 0.4%); Tamol(~) 983 polyacid dispersant (9.2 gm, 0.9%); Tint-Ayd(~) WD 2345 pigment dispersion (9.2 gm~ 0.9%); and ColloidTM 646 emulsifiable liguid foam control agent (0.5 gm, 0.1%). The following components were added to this mixture with mixing at medium speed: Daratak(~) 3631 vinylidene chloride based adhesive emulsion (104.1 gm, 10.4%), which is available from W.R. Grace & Co. Orgarlic Chemicals Division (Lexington, MA); AMP-~STM (2-amino-2-methyl-1-propanol with 5% water, 1.0 gm, 0.1%); and ArolonTM 870 (EA-6556) styrene-butadiene emulsion (174.9 gm, 17.5%). To this mixture was added DualiteTM M6017AE-04 hollow composite microsphere filler (18.4 gm, 1.8%), which is available from Pierce &
Stevens Corp. (Buffalo, NY). Snowhite 20 calcium/magnesium carbonate (312.3 gm.
31.2%), which is available from Steep Rock Resources Inc. (Pickering, Ontario, Canada), was then added in small increments, followed by sodium potassium alumina silicate (312.3 gm, 31.2%) in small increments and the resultant mixture was mixed until smooth. Finally, the following components were added in order, with mixing:
OnyxideTM-200 preservative (hexahydro-],3,5-tris(2-hydroxyethyl)-s-triazine, 0.5 gm, 0.1%), which is available to Metal Working Chemicals & Equipment Co., Inc. (LakePlacid, NY); TexanolTM ester-alcohol (2,2,4-trimethyl-1,3-pentanediol monoisobutyrate, 1.3 gm, 0.1%); and Acrysol(~ TT-615 acrylate thickener (0.5 gm, 0.1%). This final composition was mixed until smooth (solids content = 80%). This composition is particularly adapted for a chip-resistant, sound-deadening, corrosion-resistant coating that can be air-dried.
2I287~
Viscosity The viscosity of this composition at 20C was determined to be 10-30 seconds (about 20,000-60,000 Centipoise) on a Sever viscometer using test method5 SAE J1524, 3.175 mm orifice, 69 kPa pressure, 50 gm sample weight).
Cold Impact Resistance The composition was coated uniformly on an electrocoated plate, i.e., a primed steel plate, obtained from ACT, Inc. to form a coating thickness of 20 mils 10 (0.5 mm). The test plate was air dried vertically for a period of 24 hours, held for 14 days at 70C, followed by at least 4 hours at -23C. The test piece was then subjected to two 1.7 J impacts. There was no cracking or peeling observed.
Salt Spray Test The composition was coated uniformly on an electrocoated plate to form a coating thickness of 20 mils (0.5 mm). The test plate was air dried vertically for a period of 72 hours, and then placed in a 38C salt spray tester for 14 days. The coating was then removed from the test piece by solvent cleaning. There was no corrosion or undercut observed.
Chip Resistance The composition was coated uniformly on an electrocoated plate to form a coating having a thickness of 20 mils (0.5 mm). The test plate was air dried for 72 hours. These panels were then left in a freeær at -10F (-23.3C) for 4 hours, 25 placed in a gravelometer, and shot with 5 pints of gravel immediately. There was no chipping or any other film failures.
Example 3 Preparation and Properties of Formulation C
Preparation A water-based coating was prepared by placing water (126.5 gm, 12.6%) into a plastic container. This was placed on an air mixer and BentoneTM LT
organoclay (0.5 gm, 0.1%) was added with mixing at a moderate speed until smoothor until particles were dispersed. The following components were then added withmixing: Foamaster(~) S defoamer (1.1 gm, 0.1%); 30% solution of Pluronic(~ F-87 block copolymer surfactant in water (11.0 gm solution, 1.1%); and Tint-Ayd(~) WD2345 pigment dispersion (8.9 gm, 0.9%). Zinc phosphate (111.0 gm, 11.1%) was then added and the composition was mixed until smooth. ArolonTM 870 (EA-6556) styrene-butadiene emulsion (407.8 gm, 40.8%) was then added with mixing. To thismixture was added TechFilTM C117 talc (333.0 gm, 33.3%), which is available fromLuzenac (Oakville, Ontario, Canada). This final composition was mixed until smooth (solids content = 65%). This composition is particularly adapted for a room-temperature sprayable corrosion-resistant coating that can be air-dried.
Viscosity The viscosity of this composition at 25C was determined to be 2500-5000 Centipoise on a Brookfield viscometer (spindle No. 5 rotation frequency = 20 rpm).
Salt Spray Test Clean cold rolled steel panels were coated with the composition at a thickness of 8-10 mils (0.2-0.25 mm) wet and air dried for 72 hours. The panels were then scribe marked and placed in a salt fog chamber (5% sodium chloride solution is sprayed) for 168 hours. No corrosion or undercutting was noted at the completion of the test.
2l~87s3 Chip Resistance The composition was coated uniformly on an electrocoated plate to form a coating having a thickness of 20 mils (0.5 mm). The test plate was air dried for 72 hours. These panels were then tested according to SAE J400 test method, left in 5 a freezer at -10F (-23.3C) for 4 hours, placed in a gravelometer, and shot with 5 pints of gravel immediately. There was no chipping or any other film failures.
Example 4 Prel)aration and Properties of Formulation D
10 Preparation A water-based coating was prepared by placing water (5.1 gm, 10.2%) into a plastic container and a 50% solution of potassium tripolyphosphate in water (2.6 gm, 0.5%) was added. This was placed on an air mixer (1/4 inch air motor) and mixing was started using a 2 inch spindle at low speed. Ethylene glycol was 15 then added (5.5 gm, 1.1%). Attagel~) 40 thickener (10.2 gm, 2.0%) was then added and the mixing speed was increased to medium. This composition was mixed for 10 minutes. The following components were added in order and the composition was then mixed at moderate speed: Tamol~) 983 polyacid dispersant (5.45 gm, 1.1%);
ColloidTM 646 emulsifiable liquid foam control agent (4.09 gm, 0.8%); and Tint-20 Ayd(~) WD 2345 pigment dispersion (5.45 gm, 1.1%). The following componentswere added in order and the composition was then mixed at moderate speed:
ArolonTM 870 (EA-6556) styrene-butadiene emulsion (136.4 gm, 27.3%); AMP-95TM
(2-amino-2-methyl-1-propanol with 5% water, 0.7 gm, 0.1%); and Haloflex 202 vinylidene chloride emulsion (68.2 gm, 13.6%). Aluminum silicate pigment ASPTM
25 400 filler (102.3 gm, 20.5%) was then added in small increments with mixing.
Polymica 325 filler (102.3 gm, 20.5%) was then added in small increments and thecomposition was mixed until smooth. The following components were then added in order with mixing: OnyxideTM-200 preservative (hexahydro-1,3,5-tris(2-hydroxyethyl)-s-triazine, 0.3 gm, 0.1%) and TexanolTM ester-alcohol (2,2,4-trimethyl-1,3-pentanediol 30 monoisobutyrate, 2.7 gm, 0.5%). Acrysol~ TT-615 acrylate thickener (1.4 gm, 0.3%) was premixed with water (1.4 gm, 0.3%) and then added to this mixture. This final composition was mixed until smooth (solids content = 66%). This composition is 21~7~3 particularly adapted for a chip-resistant, corrosion-resistant coating over a primed or topcoated surface that can be either baked or air-dried.
Viscosity The viscosity of this composition at 20C was determined to be 15,000 Centipoise on a Brookfield viscometer (BH-type, rotor No. 6 rotation frequency = 20 rpm). The viscosity of an aged sample of the composition at 20C was determined to be about 15,000-20,000 Centipoise. The composition was aged by placing a sealed container containin~ the sample in a thermostatic vessel adjusted to 50C for 10 days, and then at 20C for 20-24 hours. The viscosity of a sample subjected to freezing and thawing of the composition at 20C was determined to be 20,000 Centipoise.
The composition was subjected to a freezing-thawing cycle three times (-5C for 16 hours and 20C for 8 hours) by placing a sealed container containing the sample in a thermostatic vessel adjusted, and finally at 20C for 20-24 hours.
Cold Bendin~ Resistance The composition was coated uniformly on a terne steel sheet, i.e., a substrate used to make automobile gas tanks, to form a dry coating thickness of 12 mils (0.3 mm). The test plate was baked for 5 minutes at 80C and then for 15 minutes in an dryer adjusted to 120C. Finally the test sample was held at room temperature for 24 hours, and then held at -30C for 3 hours. The test piece wasthen bent immediately at an angle of 180 uniformly along a mandrel of 25 mm diameter in a period of about 5 seconds, with the coated surface of the test piece facing outward. There was no peeling observed.
Salt Spray Test Two terne sheets were welded together and coated uniformly such that the coating thickness was 12 mils (0.3 mm). The test plate was baked for 5 minutes at 80C and then for 15 rninutes in an dryer adjusted to 120C, then cooled to room temperature over a 24 hour period. The test piece was then placed in a 38C saltspray tester at an angle of 70 from horizontal for 42 days. The test procedure carried out was ASTM B117. After 42 days, the test piece was removed and the 212~753 -coating was cleaned off within I hour. There was little or no corrosion or undercut observed.
Bakin~ Test 5A 50 mil (1.3 mm) coating of the composition was applied to a terne sheet panel. The panel was then baked at 176F (80C) for 5 minutes, and then at248F (120C) for 15 minutes. No blistering was observed. Furthermore, the coating displayed excellent adhesion and chipping resistance.
10Chip Resistance The composition was coated uniformly on a terne sheet to form a coating thickness of 12 mils (0.3 mm). The test plate was baked for 5 minutes at 80C and then for 15 minutes at 120C, and finally held at room temperature for 24 hours.The coated test piece was placed in a testing apparatus at an angle of 60 from 15horizontal with a funnel (20 mm inside diameter, 2000 mm overall length) placed 5-10 mm above the surface of the test piece. Brass nuts previously dropped on a sample paper board 700 times were dropped onto the center of cross-cut in coating through the funnel. The total mass of nuts needed to abrade the coating was 27 kg.
A second test piece was prepared in a manner analogous to the first test 20piece, but with the additional treatment steps of holding the test piece for 10 days in a thermostatic water bath at 40C. The test piece was subjected to the same procedure as described above within 2-5 hours of taking it out of the water bath.
The total mass of nuts needed to abrade the coating was 21 kg.
Examples 5-7 Preparation and Properties of Formulations E, F, & G
Preparation Each water-based coating was prepared by placing water (75.0 gm, 3010.4%) into a plastic container and a 50% solution of potassium tripolyphosphate in water (3.8 gm, 0.5%) was added. This was placed on an air mixer (1/4 inch air motor) and mixing was started using a 2 inch spindle at low speed. Ethylene glycol was then added (8.0 gm, 1.1%). Attagel(~) 40 thickener (15.0 gm, 2.1%) was then added and the mixing speed was increased to medium. Each composition was mixed for 10 minutes. The following components were added in order to each compositionand then mixed at moderate speed: ColloidTM 646 emulsifiable liquid foam control5 agent (4.0 gm, 0.6%); and Tint-Ayd(~ WD 2345 pigment dispersion (8.0 gm, 1.1%).
The following components were added in order to each composition and then mixed at moderate speed: ArolonTM 870 (EA-6556) styrene-butadiene emulsion (300.0 gm, 41.5%); and AMP-95TM (2-arnino-2-methyl-1-propanol with 5% water, 1.0 gm, 0.1%).Either Kaopaque 10 del~min~t~d aluminum silicates (300.0 gm, 41.5%, Composition 10 E), which is available from Georgia Kaolin (Union, NJ), SER-X hydrous aluminasilica (300.0 gm, 41.5%, Composition F), or Polymica 325 mica (300.0 gm, 41.5%, Composition G) was then added in small increments to each composition and then mixed until smooth. The following components were then added to each compositionin order, with mixing: OnyxideTM-200 preservative (hexahydro- 1,3,5-tris(2-15 hydroxyethyl)-s-triazine, 0.5 gm, 0.1%) and TexanolTM ester-alcohol (2,2,4-trimethyl-1,3-pentanediol monoisobutyrate, 4.0 gm, 0.6%). Acrysol(~) TT-615 acrylate thickener (1.0 gm, 0.1%) was prernixed with water (2.0 gm, 0.3%) and then added to each mixture. This final compositions were mixed until smooth (solids content = 66%).These compositions are particularly adapted for a chip-resistant, 20 corrosion-resistant, sound-deadening coatings over a primed or topcoated surface.
Composition E containing Kaopaque 10 del~min~ted aluminum silicates is particularly well adapted for baking a wet coating, i.e., a coating that has not been previously air dried, at a high film thickness without blistering.
Viscosity Using a Severs viscometer (parameters: 0.125 inch orifice, 10 psi, 50 gm), the viscosities of these compositions at 20C were determined to be: 40 seconds (90,000 Centipoise) for Composition E; 32 seconds (50,000 Centipoise) for 30 Composition F; and 46 seconds (80,000 Centipoise) for Composition G.
212~7~3 _ Bakin~ Test A 50 mil (1.3 mm) coating of each composition was applied to a terne coat panel. The panel was then baked at 266F (130C) for 20 minutes. All coatings displayed excellent adhesion. The coating prepared from Composition E displayed 5 no blisters. The coating prepared from Composition F displayed a few very small blisters.
Chip Resistance The composition was coated uniformly on an electrocoated plate to form 10 a coating thickness of 20 mils (0.5 mm). The test plate was air dried for 30 minutes, then baked at 130C for 20 minutes. The coated test piece was placed in a testing apparatus at an angle of 60 from horizontal with a funnel (20 mm inside diameter, 2000 mm overall length) placed 5 mm above the surface of the test piece. Brass nuts were dropped through the funnel onto the center of a cross cut in the coating. The 15 total mass of nuts needed to abrade the coating was 56 kg. This test was repeated on another test plate after 11 days of soaking in water, with 42 kg of nuts needed to abrade the surface.
All percentages used herein are weight percents unless otherwise noted.
The complete disclosure of all patents, patent documents, and publications cited herein 20 are incorporated by reference. The foregoing detailed description and examples have been given for clarity of understanding only. No unnecessary limitations are to be understood therefrom. The invention is not limited to the exact details shown and described, for variations obvious to one skilled in the art will be included within the invention defined by the claims.
Claims (20)
1. A water-based coating composition comprising:
(a) a styrene-butadiene emulsion;
(b) an effective amount of a filler; and (c) an effective amount of a thickener;
wherein said water-based coating composition has a viscosity of at least about 3000 Centipoise under ambient conditions.
(a) a styrene-butadiene emulsion;
(b) an effective amount of a filler; and (c) an effective amount of a thickener;
wherein said water-based coating composition has a viscosity of at least about 3000 Centipoise under ambient conditions.
2. The water-based coating composition of claim 1 wherein the viscosity is at least about 3000 Centipoise and no greater than about 20,000 Centipoise.
3. The water-based coating composition of claim 1 wherein the styrene-butadiene emulsion is present in an amount of about 10-50 wt-%.
4. The water-based coating composition of claim 1 wherein the filler is present in an amount of about 30-70 wt-%.
5. The water-based coating composition of claim 4 wherein the thickener is present in an amount of at least about 0.1 wt-% and no more than about 3 wt-%.
6. The water-based coating composition of claim 1 wherein a coating prepared from the composition and having a thickness of at least about 20 mils can be cured at a temperature of about 200-300°F without blistering.
7. The water-based coating composition of claim 1 wherein the filler is a non-mica based filler.
8. The water-based coating composition of claim 7 wherein the thickener is an acrylate thickener.
9. The water-based coating composition of claim 1 wherein the composition has a solids content of about 60-80 wt-%.
10. A water-based coating composition comprising:
(a) about 10-50 wt-% styrene-butadiene emulsion;
(b) about 30-70 wt-% filler; and (c) about 0.1-3 wt-% thickener;
wherein said water-based coating composition has a viscosity of at least about 3000 Centipoise under ambient conditions and a solids content of about 60-80 wt-%.
(a) about 10-50 wt-% styrene-butadiene emulsion;
(b) about 30-70 wt-% filler; and (c) about 0.1-3 wt-% thickener;
wherein said water-based coating composition has a viscosity of at least about 3000 Centipoise under ambient conditions and a solids content of about 60-80 wt-%.
11. The water-based coating composition of claim 10 wherein the filler is an aluminum silicate and the thickener is an acrylate thickener.
12. The water-based coating composition of claim 11 wherein the thickener is a mixture of an acrylate thickener and a magnesium aluminum silicate thickener.
13. The water-based coating composition of claim 12 wherein a coating prepared from the composition and having a thickness of at least about 20 mils can be cured at a temperature of about 200-300°F without blistering.
14. The water-based coating composition of claim 10 further including no more than about 15 wt-% of a secondary film-former.
15. The water-based coating composition of claim 14 wherein the secondary film-former is a vinylidene chloride emulsion.
16. The water-based coating composition of claim 10 further including an organic solvent in an amount less than about 5 wt-%.
17. A coating prepared from a water-based composition comprising:
(a) about 10-50 wt-% styrene-butadiene emulsion;
(b) about 30-70 wt-% filler; and (c) about 0.1-3 wt-% thickener;
wherein said water-based coating composition has a viscosity of at least about 3000 Centipoise under ambient conditions and a solids content of about 60-80 wt-%.
(a) about 10-50 wt-% styrene-butadiene emulsion;
(b) about 30-70 wt-% filler; and (c) about 0.1-3 wt-% thickener;
wherein said water-based coating composition has a viscosity of at least about 3000 Centipoise under ambient conditions and a solids content of about 60-80 wt-%.
18. A method of treating a vehicle for resistance to environmental attack comprising:
(a) coating the underbody of the vehicle with a water-based coating composition comprising:
(i) a styrene-butadiene emulsion;
(ii) an effective amount of a filler; and (iii) an effective amount of a thickener;
wherein said water-based coating composition has a viscosity of at least about 3000 Centipoise under ambient conditions; and (b) curing the coating.
(a) coating the underbody of the vehicle with a water-based coating composition comprising:
(i) a styrene-butadiene emulsion;
(ii) an effective amount of a filler; and (iii) an effective amount of a thickener;
wherein said water-based coating composition has a viscosity of at least about 3000 Centipoise under ambient conditions; and (b) curing the coating.
19. The method of claim 18 wherein the curing step comprises baking the coating at a temperature of about 200-300°F.
20. The method of claim 18 wherein the water-based coating composition comprises:
(a) about 10-50 wt-% styrene-butadiene emulsion;
(b) about 30-70 wt-% filler;
(c) about 0.1-3 wt-% thickener;
(d) about 0.05-1 wt-% defoaming agent; and (e) about 0.1-2 wt-% dispersant;
wherein said water-based coating composition has a viscosity of at least about 15,000 Centipoise and a solids content of about 60-80 wt-%.
(a) about 10-50 wt-% styrene-butadiene emulsion;
(b) about 30-70 wt-% filler;
(c) about 0.1-3 wt-% thickener;
(d) about 0.05-1 wt-% defoaming agent; and (e) about 0.1-2 wt-% dispersant;
wherein said water-based coating composition has a viscosity of at least about 15,000 Centipoise and a solids content of about 60-80 wt-%.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US18600594A | 1994-01-24 | 1994-01-24 | |
| US08/186,005 | 1994-01-24 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2128753A1 true CA2128753A1 (en) | 1995-07-25 |
Family
ID=22683275
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2128753 Abandoned CA2128753A1 (en) | 1994-01-24 | 1994-07-25 | Water-based coating composition |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2128753A1 (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6531541B1 (en) | 2000-05-19 | 2003-03-11 | Ppg Industries Ohio, Inc. | Coating compositions, coated substrates and methods for inhibiting sound transmission through a substrate |
| WO2012095520A2 (en) | 2011-01-14 | 2012-07-19 | Newlife Paints Limited | Method for manufacturing emulsion paint |
| CN103382323A (en) * | 2013-07-08 | 2013-11-06 | 吴江市物华五金制品有限公司 | Cold-resistant coating for outdoor facilities and preparation method thereof |
-
1994
- 1994-07-25 CA CA 2128753 patent/CA2128753A1/en not_active Abandoned
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6531541B1 (en) | 2000-05-19 | 2003-03-11 | Ppg Industries Ohio, Inc. | Coating compositions, coated substrates and methods for inhibiting sound transmission through a substrate |
| WO2012095520A2 (en) | 2011-01-14 | 2012-07-19 | Newlife Paints Limited | Method for manufacturing emulsion paint |
| CN103382323A (en) * | 2013-07-08 | 2013-11-06 | 吴江市物华五金制品有限公司 | Cold-resistant coating for outdoor facilities and preparation method thereof |
| CN103382323B (en) * | 2013-07-08 | 2016-02-24 | 苏州新奇迅网络有限公司 | Outdoor facilities Cold resistant paint and preparation method thereof |
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| Date | Code | Title | Description |
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