Undercoating and Articles of Manufacture Coated Therewith

Abstract

The present invention is directed to an undercoating composition comprising: a) a vinyl chloride-vinyl acetate copolymer obtained by polymerization of a co-monomer mixture comprising, based on the total weight of the co-monomers, from 85 to 98 wt. % of vinyl chloride, from 2 to 10 wt. % of vinyl acetate and from 0 to 5% by weight of a co-monomer selected from C.sub.2 to C.sub.8 olefins, vinylidene chloride and styrene; b) plasticizer comprising or consisting of at least one epoxidized natural oil; and, c) at least one aliphatic, cycloaliphatic or aromatic compound having a blocked isocyanate group, wherein said isocyanate group is blocked with a blocking agent capable of de-blocking at a temperature in the range of +/20 C. compared to the de-blocking temperature of the corresponding isocyanate being blocked with nonylphenol.

Claims

1. An undercoating composition comprising: a) a vinyl chloride-vinyl acetate copolymer obtained by polymerization of a co-monomer mixture comprising, based on the total weight of the co-monomers, from 85 to 98 wt. % of vinyl chloride, from 2 to 10 wt. % of vinyl acetate and from 0 to 5% by weight of a co-monomer selected from C.sub.2 to C.sub.8 olefins, vinylidene chloride and styrene; b) a plasticizer comprising at least one epoxidized natural oil; and, c) at least one aliphatic, cycloaliphatic or aromatic compound having a blocked isocyanate group, wherein said isocyanate group is blocked with a blocking agent capable of de-blocking at a temperature in the range of +/20 C. compared to the de-blocking temperature of the corresponding isocyanate being blocked with nonylphenol.

2. The undercoating composition according to claim 1, wherein said vinyl chloride-vinyl acetate copolymer a) is obtained by polymerization of a co-monomer mixture consisting of, based on the total weight of the co-monomers: from 90 to 98 wt. % of vinyl chloride; and from 2 to 10 wt. % of vinyl acetate.

3. The undercoating composition according to claim 1, wherein said vinyl chloride-vinyl acetate copolymer a) has a number average molecular weight (Mn) of from 30000 to 50000 g/mol.

4. The undercoating composition according to claim 1, wherein said vinyl chloride-vinyl acetate copolymer a) comprises from 20 to 40 wt. % of the undercoating composition.

5. The undercoating composition according to claim 1, wherein at least one of the epoxidized natural oils of said plasticizer b) has an acid value of less than 1 mg KOH/g.

6. The undercoating composition according to claim 1, wherein said plasticizer b) comprises epoxidized soybean oil.

7. The undercoating composition according to claim 1, wherein said epoxidized natural oil(s) constitutes from 2 to 10 wt. % of the undercoating composition.

8. The undercoating composition according to claim 1, wherein the at least one aliphatic, cycloaliphatic or aromatic compound having a blocked isocyanate group c) constitutes from 2 to 10 wt. % of the undercoating composition.

9. The undercoating composition according to claim 1 comprising, based on the weight the composition: from 20 to 40 wt. % of the vinyl chloride-vinyl acetate copolymer; from 5 to 7 wt. % of epoxidized soybean oil in the plasticizer; and from 5 to 7 wt. % of said at least one aliphatic, cycloaliphatic or aromatic compound having a blocked isocyanate group.

10. The undercoating composition according to claim 1 wherein the blocking agent is selected from a phenol; an oxime; a lactam; a secondary amine; a pyrazole; an imidazole; a triazole; and combinations thereof.

11. The undercoating composition according to claim 1 wherein the blocking agent is selected from phenol, nonylphenol, cresol, butanone oxime, cyclohexanone oxime, s-caprolactam, diisopropyl-amine, dimethylpyrazole, imidazole, triazole and combinations thereof.

12. The undercoating composition according to claim 1 wherein the blocking agent is selected from nonylphenol, 3,5 dimethylpyrazole and N-t-butylbenzyl amine.

13. A protective coating for a ferrous substrate comprising the undercoating composition of claim 1.

14. A vehicle underbody having a coating thereon comprising the undercoating composition of claim 1.

15. A method of forming a coated article, comprising: providing the undercoating composition of claim 1; providing an article having a surface; applying the undercoating composition to the surface of said article to form an undercoated substrate; applying a first coating composition onto said applied undercoating composition, wherein the undercoating composition is in an uncured state upon application of the first coating composition; and curing said undercoating and said first coating composition.

16. The method according to claim 15, wherein said undercoated substrate is stored for at least 1 hour before applying the first coating composition thereon.

17. The method according to claim 15, further comprising applying a second coating composition onto said first coating composition, wherein no curing of the applied undercoating, first coating or second coating compositions is effected until all of the undercoating, first coating and second coating compositions have been applied.

18. An article of manufacture obtained by the method of claim 15.

Description

DETAILED DESCRIPTION

Copolymer a)

[0040] The undercoating composition of the present invention includes a vinyl chloride-vinyl acetate copolymer obtained by polymerization of a co-monomer mixture comprising, based on the total weight of the co-monomers: from 85 to 98 wt. % of vinyl chloride; from 2 to 10 wt. % of vinyl acetate; and, 0 to 5% by weight of a co-monomer selected from C.sub.2 to C.sub.8 olefins, vinylidene chloride and styrene. This copolymerwhich may be referred to herein as the plastisol copolymershould constitute from 20 to 40 wt. % and desirably from 20 to 35 wt. % of the undercoating composition.

[0041] In a preferred embodiment the plastisol copolymer is characterized by being obtained by polymerization of a co-monomer mixture consisting of, based on the total weight of the co-monomers: from 90 to 98 wt. %, in particular from 95 to 98 wt. % of vinyl chloride; and from 2 to 10 wt. %, in particular from 2 to 5 wt. % of vinyl acetate. In a further embodiment, which is not intended to be mutually exclusive, the plastisol copolymer may be characterized by a number average molecular weight (Mn) of from 30000 to 50000 g/mol.

[0042] Polymerization methods for the synthesis of such copolymers are known in the art, for instance in U.S. Pat. No. 3,172,877 (Fishbein) and U.S. Pat. No. 7,915,364 (Assignee: Wacker Chemie AG). Moreover, suitable plastisol copolymers include known commercial products: in this regard KCH-12 (available from Hanwha) and Lacovyl PA 1384 (available from Arkema) may be mentioned.

Plasticizer b)

[0043] The plasticizer b) of the coating composition is characterized in that it comprises or consists of at least one epoxidized natural oil. This epoxidized natural oil should constitute at least 2 wt. %, preferably from 2 to 10 wt. % and more preferably from 4 to 8 wt. % of the coating composition.

[0044] In an embodiment, plasticizer b) comprises or consists of at least one epoxidized natural oil selected from the group consisting of: epoxidized algae oil; epoxidized beef tallow oil; epoxidized canola oil; epoxidized avocado oil; epoxidized castor oil; epoxidized corn oil; epoxidized peanut oil; epoxidized fish oil; epoxidized linseed oil; epoxidized palm oil; epoxidized rapeseed oil; epoxidized hempseed oil; epoxidized safflower oil; epoxidized soybean oil; epoxidized sunflower oil; epoxidized tall oil; epoxidized tung oil; and, any combination thereof. More particularly, it is preferred that the plasticizer b) comprises or consists of epoxidized soybean oil.

[0045] In a further embodiment, which is not intended to be mutually exclusive, the plasticizer b) comprises or consists of at least one epoxidized natural oil, wherein the or each epoxidized natural oil is characterized by an acid value of less than 1 mg KOH/g, preferably less than 0.95 mg KOH/g and more preferably less than 0.9 mg KOH/g.

[0046] The modification of natural oils, such as soybean oil, by epoxidation is established in the art. The attention of the skilled reader may, for example, be directed to: US 2016096916 (Webster et al.); Carlson, K. D., et al., J. Am. Oil Chem. Soc., 62: 934-939 (1985); and, Piazza, G. J., Some Recent Advances in Epoxide Synthesis in Recent Developments in the Synthesis of Fatty Acid Derivatives, AOCS Press, Champaign, 1999, pp. 182-195. Epoxidized oils may, in particular, be generated on an industrial scale using peracids, which are themselves generated by reacting formic or acetic acid with hydrogen peroxide in the presence of a strong acid catalyst (Gan, L. H., et al., J. Am. Oil Chem. Soc., 69: 347-351 (1992)). The enzymatic synthesis of inter alia epoxidized soybean oil is also known in the art, in which regard the attention of the skilled reader may be directed to U.S. Pat. No. 6,485,949 B1 (Piazza et al.). And still further epoxidation mechanisms are disclosed in: U.S. Pat. No. 5,318,808 (Crivello et al.); CN106947603 A (Foshan City Gaoming Shengjun Chemical Co. Ltd); CN106831654 A (Univ. Shaoyang); CN 106831655 A (Univ. Shaoyang). For completeness, it is not intended to limit the present application to any particular method of epoxidation of the natural oils or, in particular, of soybean oil, nor is it intended to limit the present application to any particular method of isolation, separation and/or purification of epoxidized natural oils from the product mixture obtained in their synthesis.

[0047] Commercial sources of epoxidized soybean oil include but are not limited to: ESBO (CAS 8013-07-8) available from Lanxess; Vikoflex 7170, available from Arkema; and, Jenkinol 680 available from Acme-Hardesty (Pennsylvania, US).

[0048] In addition to the aforementioned epoxidized esters, the plasticizer component b) of the present composition may comprise additional plasticizing compounds in an amount such that the overall plasticizer component b) constitutes up to 40 wt. % or up to 20 wt. %, based on the total weight of the composition. Any such additional plasticizing compounds are preferably selected from the group consisting of: polydimethylsiloxanes (PDMS); diurethanes; ethers of monofunctional, linear or branched C.sub.4-C.sub.16 alcohols, such as Cetiol OE (obtainable from Cognis Deutschland GmbH, Dsseldorf); esters of abietic acid, butyric acid, thiobutyric acid, acetic acid, propionic acid esters and citric acid; esters based on nitrocellulose and polyvinyl acetate; fatty acid esters; dicarboxylic acid esters; C.sub.1-C.sub.8 alkyl esters of OH-group-carrying or epoxidized fatty acids; glycolic acid esters; benzoic acid esters; phthalic acid esters; phosphoric acid esters; sulfonic acid esters; trimellitic acid esters; epoxidized plasticizers; polyether plasticizers, such as end-capped polyethylene or polypropylene glycols; polystyrene; hydrocarbon plasticizers; chlorinated paraffin; and, mixtures thereof.

Adhesion Promoter c)

[0049] The undercoating composition comprises c) at least one aliphatic, cycloaliphatic or aromatic compound having a blocked isocyanate group, wherein said isocyanate group is blocked with a blocking agent capable of de-blocking at a temperature in the range of +/20 C. compared to the de-blocking temperature of the corresponding isocyanate being blocked with nonylphenol. Blocking agents meeting this criterion but also having de-blocking temperatures of less than 145 C., less than 140 C. or less than 135 C. are important.

[0050] Said at least one aliphatic, cycloaliphatic or aromatic compound having a blocked isocyanate group (component c)) should constitute at least 2 wt. %, preferably from 2 to 10 wt. % and more preferably from 4 to 8 wt. % of the coating composition.

[0051] The blocked isocyanate compound may be prepared by standard procedures well known to a person skilled in the art: a polyisocyanate and a blocking agent are typically mixed together and heated to promote the reaction thereof. Commonly, the reaction temperature will be within the range from 10 C. to 100 C., for example from 30 C. to 60 C. A catalyst to promote blocking may also be used.

[0052] Suitable reactant polyisocyanates should possess at least two isocyanate groups. As exemplary reactant polyisocyanates might therefore be mentioned: toluene 2,4-diisocyanate; toluene 2,6-diisocyanate; diphenylmethane 2,4- and/or 4,4-diisocyanate; hexamethylene 1,6-diisocyanate; m-xylylene diisocyanate; p-xylylene diisocyanate; tetramethylene diisocyanate; 1-isocyanato-3,3,5-trimethyl-5-isocyanato-methylcyclohexane (or isophorone diisocyanate, IPDI); tetramethylxylylene diisocyanate; propylene 1,2-diisocyanate; 2,2,4-trimethylene diisocyanate; tetramethylene diisocyanate; butylene 2,3-diisocyanate; dodecane 1,12-diisocyanate; cyclohexane 1,3- and 1,3-diisocyanate; perhydro-2,4 and/or 4,4-diphenylmethane diisocyanate; phenylene 1,3- and 1,4-diisocyanate; 3,2- and/or 3,4-diisocyanato-4-methyldiphenylmethane; naphthalene 1,5-diisocyanate; triphenylmethane 4,4-triisocyanate; and, mixtures of said compounds while toluene-diisocyanates are specially preferred reactant polyisocyanates.

[0053] In addition to said simple isocyanates, those compounds that contain heteroatoms in the group linking the isocyanate groups are also suitable for preparing the blocked isocyanate compounds c). Examples thereof are polyisocyanates having carbodiimide groups, allophanate groups, isocyanurate groups, urethane groups, acylated urea groups and biuret groups.

[0054] Suitable polyisocyanates are, moreover, the known pre-polymers having terminal isocyanate groups of the genus that are accessible by the reaction of the above-mentioned simple polyisocyanatesand in particular diisocyanateswith sub-stoichiometric quantities of organic compounds with at least two groups that are reactive towards isocyanate groups. As said organic compounds, particular mention may be made of oligomeric or polymeric polyhydric alcohols having a number average molecular weight (Mn) of from 300 to 10000 g/mol or from 400 to 6000 g/mol and which are selected from the group consisting of: polyether polyols; polyester polyols; polyesteramide polyols; polycarbonate polyols; polybutadiene polyols; polyurethane polyols; polyacrylate polyols; and, combinations thereof.

[0055] For completeness, procedures for forming isocyanate-terminated pre-polymers are established in the art: the skilled reader may, for reference, be directed to: U.S. Pat. Nos. 4,294,951; 4,555,562; 4,182,825; and, WO2004/074343.

[0056] Examples of blocking agents that may be used, either individually or in combination, include but are not limited to: phenols, such as phenol, nonylphenol or cresol; oximes, such as butanone oxime and cyclohexanone oxime; lactams, such as s-caprolactam; secondary amines, such as diisopropyl-amine; pyrazoles, such as dimethylpyrazole; imidazoles; and, triazoles. A preference for nonylphenol, 3,5 dimethylpyrazole and N-t-butylbenzyl amine might be mentioned in this regard, while nonylphenol is especially preferred.

[0057] The blocking agent is reacted with the polyisocyanate in an amount such that the equivalents of the blocking groups of the blocking agent correspond to at least 60 mol. %, preferably 75 mol. %, more preferably 85 mol. % and most preferably more than 95 mol. % of the amount of isocyanate groups to be blocked. Often a small excess of blocking agent can be advantageous in order to ensure complete reaction of all isocyanate groups but said excess should not be more than 20 mol. %. In any event, the blocked isocyanate chemical structure may be confirmed by Proton Nuclear Magnetic Resonance (.sup.1H-NMR) and/or Fourier Transform Infrared spectroscopy (FTIR).

[0058] It is noted that component c) of the undercoating composition may comprise or consist of an aliphatic, cycloaliphatic or aromatic compound having a blocked isocyanate group and at least one other different functional group selected from: (meth)acryloyl; vinyl; allyl; maleinimido; trialkoxysilyl; and haloalkyl. As examples thereof may be mentioned: blocked trialkoxysilylpropyl isocyanates, such as triethoxysilylpropyl isocyanate or trimethoxysilylpropyl isocyanate blocked with 3,5-dimethylpyrazole; blocked isocyanatoalkyl(meth)acrylates, such as isocyanatoethyl(meth)acrylate en blocked with 3,5-dimethylpyrazole; and, Isocyanatoethyl(meth)acrylate blocked with butanone oxime, available from Showa Denko K. K. as KarenzMOI-BM.

[0059] Further exemplary commercial products, for use in or as component c) of the coating composition, include Nourybond 289 and Nourybond 290 available from Air Products and Chemicals.

Additives and Adjuvants

[0060] The undercoating composition of the present invention will typically further comprise adjuvants and additives that can impart improved properties to these compositions. Included among such adjuvants and additives are: catalysts; hardeners; solvents; stabilizers; anti-blistering agents; fillers; wetting agents; drying agents or moisture scavengers; flame retardants; rheological adjuvants; corrosion inhibitors; color pigments; and, pigment dispersants. The undercoating composition may comprise up to 70 wt. %, based on the weight of the composition, of said additives and adjuvants in toto.

[0061] The undercoating compositions of the present invention do not require catalysts. In certain embodiments, however, it may be advantageous to enable to enhance the deblocking of component c) through the use of known catalysts. Such catalysts may comprise Lewis bases, Lewis acids and/or insertion catalysts, as described in Ullmann's Encyclopedia of Industrial Chemistry, 5th Edition, 1992, Volume A21, pp. 673 to 674. For example, suitable catalysts include tin octylate, dibutyltin diacetate, dibutyltin dilaurate, dibutyltin mercaptide, dibutyltin dimaleate, dimethyltin diacetate, dimethyltin dilaurate, dimethyltin mercaptide, dimethyltin dimaleate, triphenyltin acetate, triphenyltin hydroxide, 1,4 diazabicyclo[2.2.2]octane, and/or triethylamine. Triorganotin materials, such as those disclosed in U.S. Pat. Nos. 5,902,871 and 5,880,178 might also find utility here.

[0062] Without intention to limit the catalytic amount of any given catalyst, the undercoating composition should conventionally comprise, by weight, up to 5000 ppm, for example from 50 to 500 ppm, of catalyst, based on the weight of the composition. The undercoating composition of the present invention may optionally comprise a compound having an active hydrogen atom which may function as a curing agent or hardener for the unblocked polyisocyanate. Upon heating to the de-blocking temperature, the reaction of the unblocked NCO groups with the reactive functional groups of hardener promotes polyurethane formation andwithout being bound by theoryan interpenetrating polymer network with the plastisol co-polymer a). For illustrative purposes, the use of amine derivatives and polyaminoamide derivatives as hardening agents is disclosed in inter alia: EP-A-214495; and, U.S. Pat. No. 5,130,402.

[0063] Solvents are an optional component of the undercoating composition which may be included to moderate the viscosity of the composition and thereby its mode of application. Suitable solvents will typically be paraffinic, naphthenic and aromatic hydrocarbons having a boiling point of from 150 to 250 C. And the amount of the solvent should be from 0 to 50 wt. %, preferably from 5-40 wt. %, based on the weight of the plastisol copolymer a).

[0064] Stabilizers for purposes of this invention are to be understood as including antioxidants, UV stabilizers and hydrolysis stabilizers. Typically herein stabilizers may constitute in toto up to 10 wt. % or up to 5 wt. %, based on the total weight of the composition. Standard commercial examples of stabilizers suitable for use herein include sterically hindered phenols and/or thioethers and/or substituted benzotriazoles and/or amines of the hindered amine light stabilizer (HALS) type. It is preferred in the context of the present invention that a UV stabilizer that carries a silyl groupand becomes incorporated into the end product upon dryingbe used: the products Lowilite 75, Lowilite 77 (Great Lakes, USA) are particularly suitable for this purpose. Benzotriazoles, benzophenones, benzoates, cyanoacrylates, acrylates, sterically hindered phenols, phosphorus and/or sulfur can also be added.

[0065] As noted, the curable undercoating compositions according to the present invention can additionally contain fillers. Suitable here are, for example, chalk, lime powder, precipitated and/or pyrogenic silicic acid, zeolites, bentonites, magnesium carbonate, diatomite, alumina, clay, talc, titanium oxide, iron oxide, zinc oxide, sand, quartz, flint, mica, glass powder, and other ground mineral substances. Organic fillers can also be used, in particular carbon black, graphite, wood fibers, wood flour, sawdust, cellulose, cotton, pulp, cotton, wood chips, chopped straw, chaff, ground walnut shells, and other chopped fibers. Short fibers such as glass fibers, glass filament, polyacrylonitrile, carbon fibers, Kevlar fibers, or polyethylene fibers can also be added. Aluminum powder is likewise suitable as a filler.

[0066] The pyrogenic and/or precipitated silicic acids advantageously have a Brunauer-Emmett-Teller (BET) surface area from 10 to 90 m.sup.2/g. When they are used, they do not cause any additional increase in the viscosity of the composition according to the present invention, but do contribute to strengthening the cured composition.

[0067] It is likewise conceivable to use pyrogenic and/or precipitated silicic acids having a higher BET surface area, advantageously from 100 to 250 m.sup.2/g, in particular from 110 to 170 m.sup.2/g, as a filler: because of the greater BET surface area, the effect of strengthening the cured composition is achieved with a smaller proportion by weight of silicic acid.

[0068] Also suitable as fillers are hollow spheres having a mineral shell or a plastic shell. These can be, for example, hollow glass spheres that are obtainable commercially under the trade names Glass Bubbles. Plastic-based hollow spheres, such as Expancel or Dualite, may be used and are described in EP 0 520 426 B1: they are made up of inorganic or organic substances and each have a diameter of 1 mm or less, preferably 500 m or less.

[0069] Fillers which impart thixotropy to the composition may be preferred for many applications: such fillers are also described as rheological adjuvants, e.g. hydrogenated castor oil, fatty acid amides, or swellable plastics such as PVC.

[0070] The total amount of fillers present in the undercoating compositions of the present invention will preferably be from 1 to 50 wt. %, and more preferably from 5 to 40 wt. %, based on the total weight of the composition. The total amount of filler will typically be determinative of the desired viscosity of the composition upon application.

[0071] Examples of suitable pigments are titanium dioxide, iron oxides, or carbon black.

Illustrative Embodiments of the Present Invention

[0072] Without intention to limit the present invention, an undercoating composition according to the present invention which has yielded good results is characterized by comprising, based on the weight the composition:

[0073] a) from 20 to 40 wt. %, preferably from 20 to 35 wt. % and more preferably from 25 to 35 wt. % of a vinyl chloride-vinyl acetate copolymer obtained by polymerization of a co-monomer mixture consisting of, based on the total weight of the co-monomers, from 95 to 98 wt. % of vinyl chloride and from 2 to 5 wt. % of vinyl acetate;

[0074] b) from 5 to 7 wt. % of epoxidized soybean oil; and,

[0075] c) from 5 to 7 wt. % of said at least one aliphatic, cycloaliphatic or aromatic compound having a blocked isocyanate group, wherein said isocyanate group is blocked with a blocking agent capable of de-blocking at a temperature in the range of +/20 C. compared to the de-blocking temperature of the corresponding isocyanate being blocked with nonylphenol.

Methods and Applications

[0076] The compositions of the present invention may be produced using mixing equipmentsuch as planetary mixers, planetary dissolvers, kneaders and internal mixersor extrusion equipment, such as twin-screw extruders, which will be familiar to those of ordinary skill in the art. The shear forces and/or duration of the mixing must be sufficient to ensure a homogenous mixture in which the copolymer a) is suspended in the plasticizer component b).

[0077] The so-mixed coating composition may then be applied to a substrate surface by conventional application methods such as flooding, dipping, brushing, roll coating, doctor-blade application, printing methods, air-atomized spray, electrostatic rotary atomizers, air-assisted spray, airless spray, high-volume low-pressure spray, air-assisted airless spray and high-speed rotation bell. The substrate surface may have been pre-treated prior to the application of the undercoating composition to remove extractives or, more particularly, to improve the wettability of the surface.

[0078] The viscosity of the undercoating composition may be from 1 to 150 Pa.Math.s, preferably 10 to 50 Pa.Math.s, as measured using a Brookfield viscometer at 20 C. As would be recognized by a skilled practitioner, the viscosities which are appropriate for different application methods vary considerably. In any event, the composition should generally be applied to the substrate surface(s) in an amount of from 1 to 50 g/m.sup.2, preferably from 5 to 30 g/m.sup.2, more preferably from 10 to 25 g/m.sup.2.

[0079] The undercoating composition as disposed upon the substrate surface may be applied as a homogeneous layer. In an alternative embodiment, the applied layer may exhibit a graded progression by which is meant that the percentage by volume of a constituent of the composition changes through the thickness of the applied layer.

[0080] As mentioned above, the use of the coating composition according to the present invention obviates the need to pass the coated substrate through an oven or heating press before further coating layer(s) are disposed thereon. This does not preclude the coated substrate from being subjected to irradiation or to streams of hot air or other gases to elevate the temperature of the undercoating and moderate its rate of drying but without elevating the temperature of the undercoating to the de-blocking temperature of the blocked polyisocyanate compound(s). It is, however, preferred that no heating means of any kind is applied to the coating. Under such circumstances, the wetted substrate can retain its compatibility with topcoats disposed thereon conditions for at least 60 minutes, for example at least 120 minutes, even for 72 hours or 96 hours under ambient conditions.

[0081] The coating layer, for instance the primer layer, which may be disposed directly over the uncured or wet undercoating composition according to the present invention can similarly be applied by any conventional methods known in the art, including by electrodeposition techniques, such as cataphoresis or galvanization. These methods, and equally the conventional methods for applying the subsequent topcoat or topcoat setsto form the finalized article of manufactureneed not be elucidated further. However, during the application of the overall paint or coating system, the temperature of the undercoating is required to be raised above the de-blocking temperature in order to cure that coating composition.

[0082] As noted above, the novel compositions of the present invention are designed primarily for the automotive industry as an undercoating for steel frames, rocker panels, wheel wells and the like. However, it is considered that the compositions may also provide a useful undercoating for other ferrous substrates which are exposed to salt and marine environments: such substrates may include steel structures for highways and bridges that are exposed to road salt, as well as the interior and exterior steel surfaces on ships and other structures on or near oceans or inland salt lakes. And the composition may find further utility as an undercoating for further ferrous substrates that require corrosion resistance and resistance to the impact of debris, including but limited to component structures of buses, ships and farm equipment and also rail equipment, such as locomotives, coaches, freight cars, street cars and subway cars.

[0083] Moreover, there is no intention to limit the composition to ferrous substrates: nonferrous articlesconstructed of Al, Cu or Mg for instanceand wood, fabrics, concrete, plastics, rubber, glass, ceramics, woven and non-woven fibers and paper may also be coated with the composition.

Various features and embodiments of the disclosure are described in the following examples, which are intended to be representative and not limiting.

Examples

[0084] The following commercial products are used in the Examples:

Exxsol D80: De-aromatized solvent available from Exxon Mobil.
Ibero Tec 3017: Adhesion Promoter, available from Ibero Chemie.
Ibero Tec 3157: Adhesion Promoter, available from Ibero Chemie.
Desmodur BL 3175: Blocked, aliphatic polyisocyanate based on HDI, available from Covestro.
Vestolit P 1353 K: PVC Resin available from VESTOLIT GmbH.
PCH-72: PVC Copolymer Resin available from Kaneka
PBM-6: PVC Copolymer Resin available from Kaneka.
ESO: Epoxidized Soybean Oil (CAS 8013-07-8) available from Lanxess.
EH 4358S: Hardener available from Adeka Ltd.
Nourybond 379: Blocked, aliphatic polyisocyanate available from Air Products and Chemicals.
Lacovyl PA 1384: Vinyl chloride, vinyl acetate (4%) copolymer available from Arkema.

[0085] The compositions defined in Table 1 below were formulated in accordance with the following protocol. 10 wt. % of the phthalate ester plasticizer was charged into a mixing vessel together with all further components of the compositions, save for the solvent, epoxidized soybean oil (where applicable) and the polyvinyl chloride resins. The mixture was subjected to a preliminary mixing step comprising 5 minutes at low speed and 20 minutes at high speed under vacuum. The solvent and 50 wt. % of the polyvinyl chloride resin(s) were then charged into the mixing vessel and the mixing step repeated. A further 10 wt. % of the phthalate ester plasticizer and the remaining 50 wt. % of the polyvinyl chloride resin(s) were then charged into the mixing vessel and the mixing step again repeated. Finally, the remainder of the plasticizer, including the epoxidized soybean oil where applicable, was charged into the mixing vessel under stirring.

TABLE-US-00001 TABLE 1 Com- Com- parative parative Example Raw Material Function Example 1 Example 2 1 Vestolit P 1353 K PVC Resin 13 4.32 PCH-72 Copolymer 8 34.52 5 Resin PBM-6 Copolymer 6 Resin Lacovyl PA 1384 Plastisol 24.4 Copolymer Diisononyl Plasticizer 31.8 30.87 19.27 phthalate ESO Plasticizer 5.5 Exxsol D80 Solvent 6 6 5 Ibero-Tec 3017 Adhesion 0.89 Promoter Ibero-Tec 3157 Adhesion 0.8 0.51 Promoter Desmodur BL Adhesion 0.6 0.93 3175 Promoter Nourybond 289 Adhesion 6.8 Promoter EH 4358S Hardener 0.7 Titanium dioxide Pigment 2 2 Carbon black Pigment 0.02 0.02 0.02 paste Calcium Filler 30.4 18.51 30.66 Carbonate & Silica Zinc & Calcium Adjuvants 1.3 1.43 2.49 Oxide

Testing Methods

[0086] The compositions as defined in Table 1 were subjected to the following tests, the results of which are provided in Table 2 herein below:

[0087] The Standard Gravity of the compositions was measured in accordance with ASTM D891-09.

[0088] Sag Resistance was measured using a multinotch applicator in accordance with ASTM D4400-99(2012)e1.

[0089] Adhesion may be measured in accordance with ASTM D 3359-93 (Standard Test Method for Measuring Adhesion by Tape Test Method B).

[0090] Chipping-resistance was evaluated using a Nut Drop Test according to the following protocol. A coating layer having a dry thickness of 100 m was applied to a planar ferrous test panel having the dimensions board size 701500.8 mm. The test panel was mounted horizontally in a frame and steel nuts (of approximately 2 cm in length) were dropped in 3 Kg units from a fixed locus into the centre of the panel. The total fall weight of nuts was recorded at the point when abnormalities such as cracks and fractures occurred in the substrate.

Wet-On-Wet Paintability Test Protocols:

[0091] i) The undercoating composition is applied to a planar ferrous test panel at a thickness of 100 microns and the coated panel allowed to stand for 10 minutes at room temperature and ambient humidity. A primer (OP-880 ZOC (L-70) from Berger Nippon) is then applied at a coating thickness of 20 microns, followed after a 5 minutes flash-off time by a base coat (SP M-700 SM ZHJ C/B from Berger Nippon) at a coating thickness of 12 microns. A further base coat (SP M-700 SM ZHJ P/B from Berger Nippon) was then applied at a coating thickness of 8 microns. After a flash-off time of 8 minutes a clear coat (SPO-100 clear SG (KAI 3) from Berger Nippon) was applied at a coating thickness of 20 microns. After a flash-off time of 10 minutes, the panel was transferred to an oven set at 140 C. for 30 minutes. The panel was removed and observed for dewetting/sagging of the paint. [0092] ii) The undercoating composition is applied to a planar ferrous test panel at a thickness of 100 microns and the coated panel allowed to stand for 72 hours at 30 C. and 80% relative humidity. A primer (OP-880 ZOC (L-70) from Berger Nippon) is then applied at a coating thickness of 20 microns, followed after a 5 minutes flash-off time by a base coat (SP M-700 SM ZHJ C/B from Berger Nippon) at a coating thickness of 12 microns. A further base coat (SP M-700 SM ZHJ P/B from Berger Nippon) was then applied at a coating thickness of 8 microns. After a flash-off time of 8 minutes a clear coat (SPO-100 clear SG (KAI 3) from Berger Nippon) was applied at a coating thickness of 20 microns. After a flash-off time of 10 minutes, the panel was transferred to an oven set at 140 C. for 30 minutes. The panel was removed and observed for dewetting/sagging of the paint. [0093] iii) The undercoating composition is applied to a planar ferrous test panel at a thickness of 100 microns and the coated panel allowed to stand for 96 hours at 30 C. and 80% relative humidity. A primer (OP-880 ZOC (L-70) from Berger Nippon) is then applied at a coating thickness of 20 microns, followed after a 5 minutes flash-off time by a base coat (SP M-700 SM ZHJ C/B from Berger Nippon) at a coating thickness of 12 microns. A further base coat (SP M-700 SM ZHJ P/B from Berger Nippon) was then applied at a coating thickness of 8 microns. After a flash-off time of 8 minutes a clear coat (SPO-100 clear SG (KAI 3) from Berger Nippon) was applied at a coating thickness of 20 microns. After a flash-off time of 10 minutes, the panel was transferred to an oven set at 140 C. for 30 minutes. The panel was removed and observed for dewetting/sagging of the paint. [0094] iv) The undercoating composition is applied to a planar ferrous test panel at a thickness of 100 microns and the coated panel allowed to stand for 192 hours at 30 C. and 80% relative humidity. A primer (OP-880 ZOC (L-70) from Berger Nippon) is then applied at a coating thickness of 20 microns, followed after a 5 minutes flash-off time by a base coat (SP M-700 SM ZHJ C/B from Berger Nippon) at a coating thickness of 12 microns. A further base coat (SP M-700 SM ZHJ P/B from Berger Nippon) was then applied at a coating thickness of 8 microns. After a flash-off time of 8 minutes a clear coat (SPO-100 clear SG (KAI 3) from Berger Nippon) was applied at a coating thickness of 20 microns. After a flash-off time of 10 minutes, the panel was transferred to an oven set at 140 C. for 30 minutes. The panel was removed and observed for dewetting/sagging of the paint.

TABLE-US-00002 TABLE 2 Comparative Comparative Example Properties Example 1 Example 2 1 Appearance Passes Passes Passes Solids Content (%) 95.2 95.3 96.2 Specific Gravity 1.36 1.25 1.34 Viscosity at 20 C. 28 17 19 (Pa .Math. s) Sagging 3 3 3 Resistance (mm) Adhesion (Room No peel off, No peel off, No peel off, Temperature) 100/100 100/100 100/100 Adhesion (After No peel off, No peel off, No peel off, Storage for 72 100/100 100/100 100/100 hours at 30 C., 50% Relative Humidity) Nut Drop Test 21 36 45 (Immediate) Nut Drop Test 18 33 42 (After Storage for 72 hours at 30 C., 50% Relative Humidity) Wet-on-Wet Paintability Tests Immediate (i) Not OK: Paint Not OK: Paint Appearance OK: Dripping Dripping no dripping After 72 hours at Not OK: Paint Not OK: Paint Appearance OK: 30 C. and 80% Dripping Dripping no dripping relative humidity (ii) After 96 hours at Not OK: Paint Not OK: Paint Appearance OK: 30 C. and 80% Dripping Dripping no dripping relative humidity (iii)

[0095] In view of the foregoing description and examples, it will be apparent to those skilled in the art that equivalent modifications thereof can be made without departing from the scope of the claims.