CA1090028A - Fluoropolymer primer compositions - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
This invention relates to a composition comprising a copolymer of ethylene and a halogenated comonomer selected from the group consisting of tetrafluoroethylene, chlorotrifluoroethy-lene and mixtures thereof and 0 to 10 mol percent of an additional monomer selected from the group consisting of 3,3,3-trifluoro-2-trifluoromethyl propene, a vinyl monomer which is free of telo-genic activity and which provides a side chain having at least two carbon atoms, said side chain being aromatic or having its ele-ments bonded together by a single bond only, or mixtures thereof, and containing from about 5 to 60 percent by weight of the total composition of an epoxy resin and from about 1 to 25 percent by weight of the total composition of an oxide of cobalt, nickel, manganese, tungsten or mixtures thereof. Such compositions are particularly useful as a primer coating for substrates such as metals in conjunction with an overlying layer of such copolymers.
Coated articles are provided which comprise a substrate, a primer coating fused thereon and comprising such composition and an outer coating of similar copolymers fused to the primer coating.

Description

iO!.~OOZ8 FLUOROPOLYMER PRIMER COMPOSITIONS
BACKGROUND OF THE_INVENTION
Fie~d of the Invention This invention relates to fluoropolymer primer compositions useful for coating substrates, particularly copolyme~
based on ethylene and a comonomer selected from the group consisting of chlorotrifluoroethylene, tetrafluoroethylene and mixtures thereof.
DESCRIPTION OF THE PR_OR ART
Copolymers of about 40 to about 60 mol percent ethylene and correspondingly from about 60 to about 4Q mol percent of chlorotrifluoroethylene, tetrafluoroethylene and mixtures thereof, are known in the art as disclosed, for example, in Mueller et al.
U.S. Patent 3,847,881, issued November 12, 1974. As described therein, such copolymers may contain 3,3,3-trifluoro-2-trifluoro-methyl propene to improve their stress-crack resistance. Also, as described in Car]son U.S.P. 3,624,250,issued November 30, 1971, such copolymers may contain certain vinyl monomers in order to improve their stress-crack resistance. Such copolyrners have been suggested as being useful for coating articles by powder coating techniques. However, it has been found that the adhesion between such copolymer coatings and the underlying 9ubs-trate, particularly in the case of metal substrates, is too weak for certain applica-tions, especially those wherein a severe environment is encoun-tered. Robertson et al. U.S.P. 3,989,873, issued November 2, 1976, describes primer coatings for such copolymers which include about 1 to 40 percent by weight of an oxide of cobalt, nickel, manganese, chromium, tin, molybdenum, tungsten or mixtures thereof. Although such primer coatings are effective for bonding such copolymers to metal and other ; 30 ,., 1 ,~

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substrates, it has been found that upon long term exposure to high temperature wet environments, the bond strength of coated articles substantially decreases. It would be desirable to pro-vide a primer coating composition and coated articles based on - such copolymers which have improved high temperature wet environment bond strengths.
è SUMMARY OF THE INVENT ON
In accordance with one embodiment of the present invention, there are provided copolymers of ethylene, a halo-genated comonomer selected from the group consisting of tetra-, fluoroethylene, chlorotrifluoroethylene and mixtures thereof -~ and 0 to 10 mol percent o~ an additional monomer selected from the group consisting of 3,3,3-trifluoro-2-trifluoromethyl propene, a vinyl monomer which is free of telogenic activity and which provides a side chain having at least two carbon atoms, said side chain being aromatic or having its elements bonded together by a single bond only, or mixtures thereof, ` and containing from about 5 to 60 percent by weight of the -~
total composition of an epoxy resin and about 1 to 25 percent by weight of the total composition of an oxide of cobalt, nickel, `~~ manganese, tungsten or mixtures thereof. Such compositions . .
are particularly useful as a primer coating for substrates such as metals, preferably in conjunction with an overlying layer of such copolymers. In accordance with another embodiment of the present invention, coated articles are provided which . ., ~ comprise a substrate, a primer coating fused thereon and com-, prising a copolymer of ethylene, a halogenated comonomer selected from the group consisting of tetrafluoroethylene, ; chlorotrifl~oroethylene and mixtures thereof and 0 to 10 mol percent of an additional monomer selected from the group consisting of 3,3,3-triflyoro-2-trifluoromethyl propene, a vinyl monomer which is free of telogenic activity and which pro-.
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: vides a side chain having at least two carbon atoms, said side - chain being aromatic or having its elements bonded together by a single bond only, or mixtures thereof, and from about 5 to 60 , percent by weight of the total composition of an epoxy resin and about 1 to 25 percent by weight of the total composition of an oxide of cobalt, nickel, manganese, tungsten or mixtures thereof, and an outer coating fused to the primer coating and comprising a copolymer of ethylene, a halogenated comonomer selected from . the group consisting of tetrafluoroethylene, chlorotrifluoroethy-- 10 lene and mixtures thereof and 0 to 10 mol percent of an additional monomer selected from the group consisting of 3,3,3-trifluoro-2-trifluoromethyl propene, a vinyl monomer which is free of telo-genic activity and which provides a side chain having at least :i two carbon atoms, said side chain being aromatic or having its elements bonded together by a single ~ond only, or mixtures thereof. Preferably, the substrate is a metal substrate and the copolymers of the primer and overlying layers are the same. It has been found that the use of such primer layers, especially those containing an oxide of cobalt, provides articles which have excellent bond strength even when exposed to prolonged high i temperature wet environments.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
As stated above, the copolymers of the present invention are known and may be prepared by known polymerization methods, such as are described in the aforesaid Mueller et al. and Carlson , patents. Preferably, the copolymers contain from about 40 . to about 60 mol percent of ethylene, from about 60 to about 40 mol percent of chlorotrifluoroethy].ene, tetrafluoroethylene or mix-, tures thereof and 0 to 10 mol percent of an additional monomer selected from the group consisting of 3,3,3-trifluoro-2-trifluoro-~B -3 1~9~ Z8 methyl propene, a vinyl monomer which is free o~ telogenic acti-vity and which provides a side chain having at least two carbon atoms, said side chain being aromatic or having its elements bonded together by a single bond only, or mixtures thereof.
bout equimolar copolymers of ethylene and chlorotrifluoro-ethylene or tetrafluoroethylene axe particularly preferred.
The termonomers disclosed in Mueller et al. (i.e., 3,3,3-trifluoro-2-trifluoromethyl propene) and in Carlson (i.e., vinyl monomers) may optionally be present in the copolymer.
Amounts of about 0.1 to about 10 mol percent, based on the total mols of the other monomers, may be employed. Preferably, about 0.5 to about 5 mol percent of such additional monomers are employed.
The monomers disclosed in Carlson are copolymerizable vinyl monomers that are free of telogenic activity and which pro-vide a side chain having at least two carbon atoms and being either aromatic or having its elements bonded together only by single bonds. By "free of telogenic activity" is meant that the vinyl monomer does not act as a chain transfer agent to an .,, extent which undesirably limits the molecular weight of the copolymer. Examples of such vinyl monomers include fluorinated alpha-mono-olefins and those of the following formulae:

R-CF=CF2; ROCF=CF2; CF3tCF2)mCH20CF=CF2; CH3~CH2)nOCF=CF2;
R'CH2(X)=CH2 and R20CH2C(X)=CH2, s; wherein R is an organic group containing 2 to 8 carbon atoms, R' is a perfluorinated or chlorofluoroalkyl group of 1 to 7 carbon atoms or a secondary or tertiary halo-alcohol group, R2 is a perfluorinated or chlorofluoroalkyl of 1 to 7 carbon atoms, X
is H or CH2, m is an integer of 0 to 6 and n is an integer of 1 to 30 7. Especially preferred vinyl monomers are perfluoropropyl per-fluorovinyl ether, 1,1,1-trifluoro-2-(trifluoromethyl)-4-penten-, . .

2-ol . `

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and allyl heptafluoroisopropyl ether.
; Preferred copolymers are those containing from about 40 to about 60 mol percent of ethylene and from about 60 to about 40 mol percent chlorotrifluoroethylene, especially about equimolar copolymers of such comonomers, as well as copolymers of ethylene and chlorotrifluoroethylene of the aforesaid mol content (and ;~ especially about an equimolar content) together with about 0.5 to 5 mol percent of 3,3,3-trifluoro-2-trifluoromethyl propene, and copolymers of ethylene and tetrafluoroethylene of the afore-- 10 said mol content (and especially about an equimolar content) together with about 0.5 to 5 mol percent of perfluoropropyl perfluorovinyl ether.
¦ The copolymers and terpolymers may include a high molecular weight fraction as is disclosed in U.S. Patents 4,020,253, issued April 26, 1977, and 4,033,939, issued ~uly 5, 1977. For example, the copolymers and terpolymers may contain about 0.5 to 60 weight percent of a high molecular weight component which has a melt index per ASTM D-]238 at 275C. of about 0.0001 to 1.0, preferably about 0.005 to 0.5, and about 99.5 to 40 weight percent of a low molecular weight component , which has a melt index of about 3 to 3000, preferably about 5 ,., ~o 1000.
The copolymer primer compositions include from about 5 to 60 weight percent, based on the total weight of the composi-tion, of an epoxy resin, and preferably from about 25 to 50 ; weight percent of such resin. The epoxy resins useful herein may be any of the known adhesive epoxy resins. Such resins may be prepared by the condensation of epoxy compounds, such as epi-chlorohydrin and g]ycerol dichlorohydrin, with polyhydric organic ~compounds ~uc as alcohole, e.g., pentaerythritol: dihydric '''~.- ., . .. , .

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alcohols, e.g., glycerol; dihydric phenols, e.g., bisphenol A;
`~ and trihydric phenols. For example, epoxy resins prepared by the condensation of bisphenol A and epichlorohydrin may be employed.
Other types of epoxy resins include diglycidyl ether of bisphenol A, the epoxidized novolac resins such as epoxy cresol novolac and epoxy phenol novolac. Still other epoxy resins include the cycloaliphatic resins in which the epoxide groups are attached directly to the cycloaliphatic portions of the molecule rather than on the alkyl chain.
The above epoxy resins include hardeners and/or accelerators which permit their curing at elevated temperature.
-- Such catalysts include Lewis bases such as tertiary amines (e.g., ~-benzyldimethylamine) and imidazoles, and Lewis bases such as boron triflyoride complexes with monoethylamine. Hardeners ` (cross-linking agents~ include primary and secondary amines - (e.g., diethylene triamine and triethylene tetramine), polyamides, ~l polyesters, carboxylic acids, anhydrides (such as maleic anhy-'.'t' dride), phenolic compounds and alcohols. The concentration of ~` such additives may vary widely depending upon the desired proper-ties in the cured material.
Such epoxy resins are commercially available as liquids or solids. When solid epoxy resins are employed they are pre-ferably in the form of aqueous emulsions or as solutions in suit-able volatile solvents such as ketonic solvents/ e.g., methyl ethyl ketone, methyl isobutyl ketone and the like; cyclic ethers such as tetrahydrofuran, etc. It has been ~ound desirable to utilize the epoxy resin as a solution in a volatile solvent since better bonding to substrates such as metals results.
The copolymer primer compositions also include from about l to 25 weight percent, preferably from about 5 to 15 weight percent, of an oxide of cobalt, nickel , manganese, tung-,. , : , 10~0028 sten or mixtures thereof. Cobalt oxide is preferred and is employed in the form of cobaltic oxide (Co2O3), although cobaltous oxide (CoO) and cobalto-cobaltic oxide (Co3O4) may also be used as well as mixtures of any two or more forms of cobalt oxide. The cobalt and other oxides are preferably em-ployed in powder form.
~ It has been found that such composltions, especially : compositions in which the copolymer is an approximate equimolar copolymer of ethylene and chlorotrifluoroethylene and contain- -ing 3,3,3-trifluoro-2-trifluoromethyl propene, are effective primer coatings for metal and other substrates. The incorpor-ation of the epoxy resins and cobalt oxides in the primer composition provides coated articles in which the outer coat-ing is firmly adhered to the substrate.
The compositions of the present invention may be pre-pared by any suitable technique known fox preparing blended thermoplastic compositons. Preferably, the epoxy resin in a `
suitable solvent is blended with pellets or powder of the co-polymer in a ribbon blender, v-cone blender or like apparatus and the solvent is removed by evaporation, vacuum or other means. Thereafter, the cobalt oxide, also preferably in pow-der form, is blended into the mixture on the same equipment.
If necessary, the final mixture may be milled to the desired size depending upon the desired method of application.
The copolymer compositions are preferably in a powder form and any of the well-known powder coating techniques may be employed to coat the compositions onto the substrate.
These techniques include electrostatic deposition and fluid-ized bed and similar techniques. As these methods are con-ventional they are not specifically described herein. It is preferred to use an electrostatic deposition coating process.

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1~)91~Z8 As is well known, this process provides initial adherence of a powder composition to a substrate and the substrate is there-; after subjected to a heat treatment above the melting point of the powder to fuse or coalesce ("flow out") the particles of the powder into a continuous layer. In forrning the coated articles of this invention, it is preferred to employ flow out temperatures in the range of about 400 to 700F., preferably about 500 to 550F. for copolymers based on ethylene and chlorotrifluoroethylene and about 450 to 800F., preferably about 575 to 650F. for copolymers based on ethylene and :.
tetrafluoroethylene or mixtures with chlorotrifluoroethylene.The duration of this heating step is dependent upon a number of factors, including the temperature employed, the coating thickness, the type of substrate, etc. In general, flow out times may conveniently be in the order of 1 or 2 minutes to -1 or 2 hours or more. Upon exposure to the elevated tempera-ture, the epoxy resin crosslinks to provide firm adhesion to the substrate.
After a continuous primer coating is formed over the substrate, a layer of particles of the outer coating may be likewise deposited on the primer coating and then heated to flow out such particles into a continuous coating which is fused to the surface of the primer layer. The composition used to form the outer coating obviously need not include the epoxy resin or the cobalt oxide. Preferably, the copolymer used in the primer and outer coatings is the same. In certain cases, it may be desirable to omit the outer coating. Alter-. ., natively, the outer layer may be deposited on the primer layer before the latter is flowed out, so that only one flow out step need be employed.
The primer composition and the outer copolymer com-position may include any of the conventional addi-tives usually .

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incorporated into such copolymer compositions. Such additives include inert fillers, stabilizers, pigments, reinforcing agents, lubricants and the like. For example, the four com-ponent stabilizing system described in U.S. Patent 3,773,698 to Khattab (1973), or the three component stabilizing system -described in U.S. Patent 3,745,145 to Khattab et al. (1973), for about equimolar ethylenechlorotrifluoroethylene copolymer compositions may be employed herein.
The various substrates capable of being coated in accordance with this invention include, for example, a metal surface such as surfaces of steel, aluminum, iron, zinc, cad-mium, magnesium, brass, bronze, Monel, Inconel; fabrics that - will withstand the baking temperatures required, such as fiber glass fabrics, asbestos fabrics, metal fabrics and the , . .
like, as well as glass and any plastic surface which will withstand high temperatures required herein without degrading.
Examples of such plastic surfaces include thermosetting resins, ~.
polyurethanes, silicones, fluoroelastomers and the like.
The type of metal or other material employed as the base layer is not critical and is dictated by the desired end use of the coated article. Especially preferred substrates are those formed of brass, bronze, aluminum, stainless steel and carbon steel. Likewise, the thickness of the substrate is not critical and is dependent upon design factors.
It is preferred to pretreat metal substrates prior to coating with the primer layer to obtain a roughened surface in order to achieve a stronger adherence of the primer coating to the substrate. Any suitable surface treatment can be employed for this purpose such as sand or grit blasting, etching, etc.
The coating itself may be deposited upon the substrate in any desired -thickness. In forming thic]s coatings (e.g. 1 _ g _ .
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mil or above) it may be desirable to employ a plurality of thin layers as is conventional in order to improve the uni-.::
formity and integrity of the coating. This of course re-quires additional exposure of the underlying coatings to high temperatures and for this reason it is preferred to include - stabilizing agents in the coating compositions.
Substrates which are coated according to this inven-tion have coated surfaces which are continuous and pinhole-free. The coatings may be employed as protective as well as ~; 10 antistick surfaces. Exemplary of articles which may be coated include wire and cable; cookware, industrial tubing, pipes, pumps and tanks, and dried rollers as well as other articles which require coatings having high strength at elevated tem-peratures, resistance to chemical attack, good electrical insulating properties, non-sticking surfaces, abrasion and scratch resistance and firm adherence of the coating.
The coated articles of this invention preferably in-clude the substrate, a layer of the primer composition of the thickness of about 0.5 to 20 mils, preferably about 1 to 10 mils, and an overlying layer of the copolymer composition having a thickness of about 0.5 to 500 mils, preferably about

3 to 50 mils.
The present invention provides a single primer layer which includes both cobalt oxide and an epoxy resin. It has ~.~
- been found that such primer layer provides excellent high tem-perature wet strength properties to coatings of such copoly-mers in an economic manner. This is especially surprising since it has been indicated in the prior art that two separate primer layers are necessary in order to provide adequate ad-hesion of perfluorohalo-olefin polymers such as polychlorotri-fluoroethylene. U.S.P. 2,979,418 to Dipner (1961) suggests ., .

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a primer system for such perfluorohaloolefin polymers (which ;~ do not include the subject copolymers~ including a first primer layer comprising the polymer and an adhesive resin such as an ` epoxy and/or phenolic resin and a second primer layer which . ~ ., .
includes the polymer and a metal oxide of a metal above the fourth group of the periodic table, such as cobalt oxide.
However, it has been found, as indicated in Example 12 below, that in contrast to the present invention, such a primer system does not provide adequate adhesion properties for the copolymers of this invention.
-~ U.S.P. 2,961,341 to Long (1960) also suggests primers ., .
; for perfluorohaloolefins (as opposed to the present copolymers) :;
but such primer layer only includes cobalt oxide. U.S. P.
~ 3,019,206 to Robb (1962) suggests latexipolyblends of poly-- tetrafluoroethylene and fluorine-containing elastomers as useful coating materials. Among the heat stabilizers suggest-ed for such blends is cobalt oxide. Although copolymers are also suggested, all of the copolymers are fluorinated or are perfluorohaloolefins. It is quite clear that this patent does not suggest the incorporation of cobalt oxide and an epoxy resin into a copolymer based on ethylene and trifluoro- ;~
` ethylene, chlorotrifluoroethylene or mixtures thereof as - adhesion promoters to provide a primer coating composition.
In order to further describe the present invention, the following non-limited examples are given. All parts and percentages are by weight.

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An equimolar ethylene-chlorotrifluoroethylene copoly-mer containing about 2 mol percent of hexafluoroisobutylene, and having a melt index of 8 to 1~, was blended in powder form with a liquid eposy resin sold by M & T Chemicals as M & T

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V;~8 primer 252 P in a weight ratio of 65% epoxy solution to 35%
fluoropolymer. The epoxy solution contained about 25 weight percent solids so that after drying the composition contained about 32 weight percent epoxy resin and 68 weight percent fluoropolymer. The mixture was dried in air for 48 hours and then dried in a vacuum oven for 16 hours at 160F. to remove -the solvents. The resultant cake was milled on a micro-pulverizer after which 10 weight percent cobalt oxide powder, based on the total weight of the composition, was added and the composition remilled to a particle size of about 60 mlcrons .
Panels of various metal substrates measuring 8 x 8 x 1/4 inch were grit blasted with 60 grit aluminum oxide. The substrates were preheated to 600F. and coated with the primer composition by electrostatic deposition. The primer coated panels were then powder coated by the same technique with the same fluoropolymer used to prepare the primer coat (but with-out the epoxy and oxide). The coated panels were vertically supported in an electrically heated air oven and the powder coatings were flowed out at 500 to 530F. for about 10 minutes.
The coated panels were subjected to a high pressure steam environment to determine the resistance and adherence of the coating. The coated plaques were exposed to 50 psig steam with a six inch diameter circle of the coating in con-taat with the steam. Following the test, the samples were examined for blisters or lift off of the coating. The results are shown in Table 1, below. In the Table, E-CTFE refers to the fluoropolymer.

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~09002 ~i As can be seen from Table 1, the primer composition of this invention provide good bond strength upon long term - exposure to steam. Comparative Example 5 demonstrates the ; poor adhesion with primer compositions that do not contain :.., epoxy resin. The incorporation of 7~ of epoxy (Example 4) provided better adherence than the comparative example and .~ the incorporation of 14% epoxy (Example 3) provided further improvement. Examples 1 and 2 demonstrate the excellent results obtained with 29% and 43% epoxy, respectively. The `- 10 knife test referred to in the Table was conducted by cut-ting an x shape into the coating of a 2 x 4 x l/4 inch panel and attempting to separate the coating from the metal substrate with a knife. Example 6 demonstrates that the primer com-position is not the limiting factor for coating integrity.
EXAMPLES_11-12 In Example 11, Example 7 was repeated on an 8 x 8 x 1/4 inch brass panel which was then subjected to the 50 psig v~ steam test. The adhesion was good after 24 hours. In Example 12 (comparative), Example 7 was repeated with two primer coats as suggested in the aforementioned U.S.P. 2,979,418. The first primer coat contained 32% by weight of the epoxy resin and no ~. ~
cobalt oxide and was applied to a thickness of about 3-5 mils.
The second primer coat contained 20% by weight cobalt oxide and no epoxy and was applied to about the same thickness. An outer coating was employed as before. In the knife test, the coating ; could be completely lifted off from the brass, which indicates ., that the prior art primer system would not provide adequate adhesion in high temperature wet environments. These examples ,., demonstrate the unexpected improvement in adhesion resulting - 30 from the present invention.
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1~90(~28 EXAMPLES 13 to 16 - Example 1 is repeated except that the primer composi- ;
tion includes, at 10 weight percent levels, nickel oxide, manga-~ .
nese oxide, tungsten oxide in Examples 13 to 15, respectively and a mixture of 5 weight percent cobalt oxide and 5 weight percent nickel oxide in Example 16. Similar results are noted.

Example 1 repeated except that the copolymer was an approximate equimolar copolymer of ethylene and tetrafluoro-F lo ethylene. Similar results are noted.

Example 17 is repeated except that the copolymer included 3 mol percent of perfluoropropyl perfluorovinyl ether. Similar results are obtained.

Example 1 is repeated except that the copolymer was an approximate equimolar copolymer of ethylene and chlorotri- --fluoroethylene. Similar results are noted.
It is to be understood that variations and modifica-tions of the present invention may be made without departing from the scope of the invention. It is also to be understood that the scope of -the invention is not to be interpreted as limited to the specific embodiment disclosed herein, but only in accordance with the appended claims when read in light of the foregoing disclosure.

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Claims (22)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE PROPERTY
OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A composition suitable for use as a primer coating comprising a copolymer of ethylene, a halogenated comonomer selected from the group consisting of tetrafluoroethylene, chlorotrifluoroethylene and mixtures thereof and 0 to 10 mol percent of an additional monomer selected from the group con-sisting of 3,3,3-trifluoro-2-trifluoromethyl propene, a vinyl monomer which is free of telogenic activity and which provides a side chain having at least two carbon atoms, said side chain being aromatic or having its elements bonded together by a single bond only, or mixtures thereof, and containing from about 5 to 60 percent by weight of the composition of an epoxy resin and about 1 to 25 percent by weight of the composition of an oxide of cobalt, nickel, manganese, tungsten and mixtures thereof.

2. A composition in accordance with claim 1 wherein said copolymers comprise from about 40 to 60 mol percent ethyl-ene and correspondingly from about 60 to about 40 mol percent of said halogenated comonomer.

3. A composition in accordance with claim 2 wherein said halogenated comonomer is chlorotrifluoroethylene.

4. A composition in accordance with claim 3 wherein said copolymer comprises from about 0.1 to about 10 mol percent of 3,3,3-trifluoro-2-trifluoromethyl propene.

5. A composition in accordance with claim 4 wherein said copolymer comprises about 0.5 to about 5 mol percent of 3,3,3-trifluoro-2-trifluoromethyl propene.

6. A composition in accordance with claim 2 wherein said epoxy resin is present in an amount of about 25 to 50 per-cent by weight.

7. A composition in accordance with claim 2 wherein said oxide is cobalt oxide.

8. A composition in accordance with claim 7 wherein said cobalt oxide is present in an amount of about 5 to 15 percent by weight.

9. A composition in accordance with claim 2 wherein said halogenated comonomer is tetrafluoroethylene.

10. A composition in accordance with claim 1 wherein said copolymer comprises from about 0.1 to about 10 mol percent of said vinyl monomer.

11. A substrate coated with the composition of claim 3

12. A substrate coated with the composition of claim 9.

13. An article of manufacture which comprises a sub-strate, a primer coating fused thereon and comprising a copolymer of ethylene, a halogenated comonomer selected from the group con-sisting of tetrafluoroethylene, chlorotrifluoroethylene and mixtures thereof and 0 to 10 mol percent of an additional monomer selected from the group consisting of 3,3,3-trifluoro-2-trifluoro methyl propene, a vinyl monomer which is free of telogenic acti-vity and which provides a side chain having at least two carbon atoms, said side chain being aromatic or having its elements bonded together by a single bond only, or mixtures thereof, and containing from about 5 to 60 percent by weight of the composi-tion of an epoxy resin and from about 1 to 25 percent by weight of the composition of an oxide of cobalt, nickel, manganese, tungsten or mixtures thereof, and an outer coating fused to said primer coating and comprising a copolymer of ethylene, a halo-genated comonomer selected from the group consisting of tetra-fluoroethylene, chlorotrifluoroethylene and mixtures thereof and 0 to 10 mol percent of an additional monomer selected from the group consisting of 3,3,3-trifluoro-2-trifluoromethyl propene, a vinyl monomer which is free of telogenic activity and which provides a side chain having at least two carbon atoms, said side chain being aromatic or having its elements bonded together by a single bond only, or mixtures thereof.

14. An article in accordance with claim 13 wherein said copolymer of said primer coating is a copolymer of about 40 to about 60 mol percent ethylene and correspondingly from about 60 to about 40 mol percent of tetrafluoroethylene, chlorotrifluoroethylene or mixtures thereof.

15. An article in accordance with claim 14 wherein said halogenated comonomer is chlorotrifluoroethylene.

16. An article in accordance with claim 15 wherein said copolymer comprises from about 0.1 to 10 mol percent of 3,3,3-trifluoro-2-trifluoromethyl propene.

17. An article in accordance with claim 16 wherein said epoxy resin is present in an amount of about 25 to about 50 weight percent.

18. An article in accordance with claim 17 wherein said oxide is cobalt oxide and is present in an amount of about 5 to 15 percent by weight.

19. An article in accordance with claim 18 wherein said copolymer of said outer coating comprises from about 40 to about 60 mol percent of ethylene and correspondingly from about 60 to about 40 mol percent of chlorotrifluoroethylene and about 0.1 to about 10 mol percent of 3,3,3-trifluoro-1 trifluoromethyl propene.

20. An article in accordance with claim 19 wherein said substrate is a metal.

21. An article in accordance with claim 20 wherein said metal is brass.

22. An article in accordance with claim 13 wherein said oxide is cobalt oxide.