CA1187233A - Hot melt corrosion resistant compositions containing epoxy resins - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE

This invention relates to a sprayable hot melt corrosion preventative composition and process for making the composition. The composition is characterized by comprising: (1) between about 10 and about 25 parts by weight of an epoxy resin elastomer adduct mixture, (2) between about 10 and about 25 parts by weight micro-crystalline wax; and (3) between about 50 and about 80 parts by weight of a dispersion of petroleum sulfonate complex in nonvolatile diluent oil. The total weight of (1), (2) and (3) is 100 parts. The composition may additionally comprise up to about 20 parts by weight of optional materials such as pigments, fillers, and/or additional nonvolatile oil. The process for making the composition includes providing the adduct mixture which is maintained at an elevated temperature, blending the wax therein, heating the dispersion and adding thereto the adduct-wax mixture.

Description

HOT MELT CORROSION RESISTANT COMPOSITIONS
_ _ O~TAINING EPOXY_RESINS
This invention relates to hot melt coating compo-sitions which possess corrosion and rust preventive proper-ties. More particularly, this invention relates to 100percent solids coating compositions containing epoxy resins and rust inhibiting sulfonates, and having low melt viscosity so as to be applicable as hot melt corrosion resistant sealers. Most particularly, the corrosion preventative compositions of the invention possess outstanding adhesion to metal substrates and comprise an adduct mixture formed by reacting epoxy resins and liquid reactive elastomer, a dispersion of petroleum sulfonate complex in nonvolatile diluent oil, and microcrystalline wax.
Inhibiting rust formation on various metal surfaces, particularly iron-containing automotive products which are exposed to salt, is highly desirable. Various solutions for preventing rust formation have been suggested in the past. It is a well known practice to coat the under body of automobiles with materials possessing corrosion preven-tive properties. To this end~ both in-point-of manufacture and after market applications, numerous materials and formu-lations have been utilized.
Most of these rust preventivc corrosion compo-sitions are based on chemically inert grease or wax-like materials. Typical of these formulations are those taught in U.S. Patents 2,374,565, 2,430,846, 2,573!878, ,~ .., ~

s ~37~2;3~3

- 2 -2~995,532~ 3,313,635~ 3,746,643 and ~,150,192. In U.S.
Patent 3,746,643, calcium and magnesium sulfonates in a minor amount of mineral oil are taught to be useful as rust inhibitor coatings when combined with a microcrystalline wax. U.S. Patent 4,150,192 teaches a sprayable hot melt rust inhibitor composite co~prised of a mixture of a sulfonate, opttonally a carbonate, optionally an oxidized petroleum, diluent oil, microcrystalline wax, actlve filler and thermoplastic re~in. The composita i~
taught as useful for coatlng automobile-~.
Because these prior art coating compositions are generally non-drying and lacking in cohesive strength, they can readily be removed by abrasion, impact, or elevated temperatures, and therefore require frequent inspection to determine the adequacy of the protection being afforded the coated metallic surface~.
Elastomers have been incorporated into rust preventative compositions in an attempt to improve their cohesive strength. Howevee, because of the extremely high ~isco~ity of such elastomers, they can only be incorporated in a ve~y limited quantity. The compositions containing hlgher le~els of elastomers have a very high viscosity and cannot be sprayed unless diluted with organic solvent.
However, the incorporation of such volatile solvents i~
undesirable for a variet~ of reasons, including potential fire hazard and toxicity. Epoxy resins generally have a lower viscosity than such elastomers and are known for their superior cohesive strength when used as a coating binder. However, due to ~he poor compatibility between

3~ epoxy resins and petroleum sulfonate complexes commonly used in rust preventative composition, epoxy resins have not been successfully- blended homogeneously into such compositions.

, .

The invention of the subject application is directed to a sprayable hot melt corrosion preventative composition and process for making the compositionO The composition is characteri~ed in that it comprises: (1) between about 10 and about 25 parts by weight of an epoxy resin-elastomer adduc~ mixture, (2) between about 10 and about 25 parts by weight microcrystalline wax, and (3) between about 50 and about 80 parts by weight of a dispersion of petroleum sulfonate complex in nonvolatile diluent oil. The total weight of (1), (2) and (3) is 100 parts.
In this composition the adduct mixture is formed by reactin~ (a) epoxy resin having a number average molecular weight (Mn) between about 150 and about 2000, preferably between about 200 and about 1500, and (ii) having two or more epoxide groups per molecule and (b) reactive elastomer (i) having a number average molecular weight (Mn) of between about 2000 and about 10,000, preferably between about 2,500 and about 5,000, (ii) having a reactive functionality capable of reacting with the epoxide group of the epoxy resin and (iii) being liquid at 20C - 25C. Epoxy resin (a) and elastomer (b) are combined in amounts providing between about 1.8 and about 3.0, preferably between about 1.8-2.5 epoxide group of the epoxy resin for each reactive functionality of the elastomer and reacted so as to convert at least about 80% of the reactive functionality of the elastomer. The nonvolatile oil of the dispersion has a boiling point of at least 230C and the sulfonate complex comprises between about 30 and about 80 weight percent of the dispersion.
The composition may additionally comprise up to about ~0 parts by weight of optional materials such as pigments, fillers, and/or additional nonvolatile oil.

72~

In the process of the subject invention for making the above descrlbed composition, the epoxy re~in and elastomer are first reacted at an elevated temperature to form an epoxy-elastomer adduct mixture. While maintaining this mixture at an elevated temperature, a microcrystalline wax is subsequently homogeneously blended into this mixture. After the dispersion of sulfonate in non-volatile diluent oil is heated to an elevated temperature, the adduct wax mixture is blended in to form a homoqeneous ~omposition.
New corrosion preventive compositions have now been found which incorporate epoxy resins and the petroleum sulfonate complex and overcome the ~eficiencies of previously known undercoating compositions to provide a hot melt sprayable coating composition exhi~iting outstanding adhesion and corrosion protec~ion to metal surEaces. The incorporation of epoxy resins with the sulfonate complex in the composition of this invention is possible, lt appears, because prior to incorporation of the sulfonate complex, the epoxy resin is reacted with elastomer to form an epoxy resin elastomer adduct. While it is known that the ~ulfonate complex lacks compatibility with epoxy resins, we have determined that the petroleum sulfonate comple~ can be admixed with the epoxy resin-elastomer adduct to form ~
homogeneous corrosion preventive composition with very desirable properties.
The composition of ~he present invention, apart ~rom producing a firm, abrasion resistant, corrosion resistant fllm, also provides a film having vibration 3~ damping and sound deadening properties. The compositions contain no organic solvents and therefore are pollution ~ee.

~87;i~33 In order to prepare the new corrosion preventive compositions of the subject invention, the epo~y resin and the liquid reactive elastomer are first combined and then reacted at elevated temperatures to form the epoxy resin elastomer adduct mixture. They are combined and reacted in an amount which provides between about 1.8 and about 3.0, preferably between about 1.8 and about 2.5, most preferably between about 2.0 and 2.5, epoxide groups of the epoxy resin for each reactive functionality of the liquid elastomer capable of reacting with the epoxide group of the resin leOg., -COOH,-NH2,-OH). Since the epoxide group is much in excess of the epoxide reactive function~-ality of the elastomer, the reaction product mixture com-prises an epoxide terminated liquid elastomer. Generally the epoxy, in liquid or particulate form, is added to the heated elastomer. The mixture is then reacted for a time and at a temperature necessary to react at least about ~0%, preferably at least about 90%, most preferably at least 95~, of the epoxide reactive functionality of the elastomer with the epoxide of the epoxy resin. The selec-tion of reaction conditions suitable for the formation of the adduct depends on the particular epoxy resin and liquid reactive elastomer used. Such time/temperature reaction conditions as are employed with particular epoxy resins-liquid reactive elastomer combinations are detailed in the examples, however, it should be borne in mind that the examples are merely exemplary of a few such compo-sitions which may be used to form the coating of the subject invention. In one embodiment, epoxy resin and carboxy functional elastomer are reacted for about 20-30 minutes at 100-110C~ The percent conversion of reactive func-tionality can be analytically followed, as, for example, ,~

~723;3 ~ ~

by tltration of th~ ~-COO~i) acld member. The ~electlon of suitable reaction conditions to effect the formation of the adduct using other suitable epoxy resins elastomer compositions within the scope of this invention and suitable methods for determining percent conversion would be well within the skill of one in the art.
Although a catalyst may be added to the epoxy resin-liquid reactive elastomer mixture to promote reaction between the epoxide group of the epoxy resin and the epoxide reactive functionality of the elastomer, such addition is neither generally required nor desirable, since the incorporation of such a catalyst may catalyze the adduct formation at too rapid a rate. However, when desirable, suitable catalysts which may be employed will be apparent to one skilled in the art, their selections of . course depending on the particular reactive functionality o the ela~tomer. Suitable catalyst to effect reaction of, for example, the epoxide (epoxy resin)/carbo~yl (elastomer) reaction include, but not limited to tetrabutylammonium chloride (or the bromide or iodide thereof), trimethyl benzylammonium chloride, 2-methyl-4-ethylimidazole, N--~ethylmorpholine~ stannou~
octoate, and zinc naphthenate.
~5 ~ecause of the non-compatibility of epoxy resins and the sulfonate dispersion, the formation of the epoxy-elastomer add~ct is an essential step to obtaining a homogeneous mixture of the corrosion preventive composition. Since the liquid reactive elastomer are generally compatible with petroleum sulfonate dispersion, and th~ adduct has the physi~al properties of liquid reactive elastomers and epoxy resins, the formation of the adduct aids in obtaining a homogeneous mixture. ~owever, while this explanation has been advanced to explain the compatibility of the sulfonate complex with the epoxy 723;~

resin-elastomer adduct, neither lts validity nor its understanding is necessary for the practice of the - invention.
A~ter formation of the adduct a~ descrihed above, between about 10 and about 25 parts by weight of microcrystalline wax is blended into between about 10 and about 25 parts by weight of the adduct mixture, while main-tainin~ the mixture at an elevated temperature0 as forexample, the 100-110C noted above. In a separate container, the petroleum sulfonate complex dispersion is heated to an elevated temperature (e.g., 100-110C). The heated adduct-wax mixture [20-50 part~ by weight) is then ` added to between about 50 and about 80 parts by weight of the sulfonate dispersion, with continuous stirring and while maintaining an elevated temperature until a uniform composition is obtained. If desired, optional materials such as pigments, fillers, and/or additional diluent oil may thereafter be incorporated. The resulting mixture i8 then u~ually removed from the mixer and cooled.
The composition thus obtained can be extruded or ~prayed as a hot melt material. ~y using a Nordson hot melt unit (Model HM-Xl available from Nordson Corporation, Amherst, Ohio), the composition can be sprayed at a temperature oE between about 120-160C.
Generally, a coating of the composition i8 applied to a substrate, typically a metal substrate, itself having a temperature in the range of about ~0C to about 40C, where it sets up generally within about 10 seconds, wlthout the reguirements of volatile solvents evaporation.
3~ Applied coatings general1y have a thickness in the range of about 3 to about 20 mils. The metal substrate itself may be bare metal, may ha~e a coat of primer on it, or may be painted before application of the hot melt composition.

~37~233 As noted above, the corrosion preventive composi-tions employ, in combination, an epoxy resin or a mixture of epoxy resins, a liquid reactive elastomer with functional groups capable of reacting with the epoxide group of the epoxy resins, petroleum sulfonate complex dispersed in oil, microcrystalline wax, and optionally pigments, fillers, and/or additional diluent oil. Each component is described in detail belo~.
Epoxy Resins The epoxy resin useful in the composition of this invention is a low molecular epoxy containing two or more epoxide groups per molecule and having a number average molecular weight (Mn) of between about 150 and about 2000, preferably between about 200 and about 1500. This epoxy resin can be a liquid or solid and can be either a single epoxy resin or a mixture cf suitable epoxy resins.
Examples of suitable diepoxides include, but are not limited to: condensation products of bisphenol-A with epichlorohydrin, examples of which are commercially avail-able as Epon* 826, 828, 1001, and 1002 (marketed by ShellChemical Gompany), Araldite* 6010 and 6020 (markei~ed by Ciba-Giegy); ester type diepoxides such as diglycidyl phthalate, diglycidyl adipate, and diglycidyl glutarate;
cycloaliphatic diepoxides such as vinyl cyclohexane dioxide and Araldite CY-179 (marketed by Ciba-Giegy Corporation);
and aliphatic ether type diepoxides such as ethylene glycol, diglycidyl ether, l,2-propylene glycol, diglycidyl ether and 17 4-butane-diol diglycidyl ether (Araldite RD-~ marketed by Ciba-Giegy). The epoxy may also be substituted with halogens such as chlorine or bromine. The incorporation of the bromine functionality in the epoxy gives fire retar-dant properties.
Especially suitable are the reaction products of epichlorohydrin and bisphenol-A having chemical formula I:
* - Trademarks ,~, .

_ 9 ~a ~.
a-y~a ~ , ... ~
'. ' "' ~ ",.
~. ..

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7~ t Such products include diglycidyl ether of bisphenol-A
(DGE8A~, i.e., when n = O~ and its higher molecular weight species. The lower molecular weight llquid product have an n value about 1 or heiow. Above nsl, the resins are S brittle solids. Preferred epoxy resins, for ~he compositions of this invention, comprise those with n=3 or less than 3, the typical properties are illustrated in Table A.
Table A
..
1~ ~elting Epoxide Molecular In ~he Formula Range, Equiva- Weight Averag~
CO lent A~erage ~alue ~o~ quia 175-210 380 O
~pon 10016~-76 ~50-550 950 2 15 ~
Other examples of epoxy compounds useful a~ the epoxy resin of this composition include polyepoxide compounds (averaging more than about 2 epoxy group per molecule). In this group of epoxy compounds are the ~o Novolac epoxy resins which are produced from the reaction of phenol and formaldehyde, subsequently with epichlorohydrin. Examples of commercially available materials in this group of epoxy compounds in~lude Cresol Novolac Araldite ECN resins 1235, 1273, 12B0 and 1299 ~marketed by Ciba-Giegy Corporation, Aedsley, N.Y.). Other commercially available Novolac resins include Epon 1138 and 1139 (marketed by Shell Chemical Company~ Houston, Texas).
While these Novolac epoxy resins have been Eound suitable for use in the corrosion composition, the epoxy 3~ resins of the subject composition preEerably co~prise diepoxides, and most preferably the DGEBA re~ins described above.

~'7233 Li~uid Reactive_Elastomers The elastorners suitable for use in the composition of this invention contain reactive functionalities, in contrast to the liquid rubber systems widely used in the area of elastomeric sealants, caulks, binders, potting-encapsulation, and structural adhesives which generally contain no such reactive groups. The reactive elastomers useful in the composition of this invention include a func-tional group, e.g., carboxyl, hydroxyl, or amino groups, with carboxyl being preferred, that will react with the epoxide group of the epoxy resin. These elastomers are low molecular weight materials having a number average molecular weight (Mn) of between about 2000 and about 10,000, and are in the liquid state at ambient temperature, i.e., 15 20 - 25C.
Examples of such liquid reactive elastomers which may be used in the composition of this invention include, but are not limited to, reactive liquid rubbers such as carboxyl-terminated butadiene polymer and carboxyl-termin-ated butadiene/acrylonitrile copolymer. Generally theseliquid rubbers contain, on the average, about 2 terminal carboxyl groups per molecule so as to be essentially con-sidered a dicarboxylic acid elastomer. Carboxyl-terminated butadiene polymer and carboxyl terminated butadiene/acryloni-trile copolymer are commercially available, for example,from B.F. Goodrich Chemical Co., Chemical Group, Cleveland, Ohio under the tradename of Hycar* polymer: 2000 x 162 (CTB), 2000 x 156 (CTB), 2000 x 165 (CTB), 1300 x 15 (CTBN), 1300 x 3 (CTBN) and 1300 x 13 (CTBN), the first three listed Hycar polymers being butadiene polymers and the last three being butadiene/acrylonitrile copolymers. ~mino terminated butadieneJacrylonitrile copolymer is likewise available, ~or example, under the tradename Hycar 1300 x 21 (BN).

* - Trademark ~J

233 h~

5uitable hydroxy terminated butadiene/acrylonitrlle copolymer is available, for example, under the tradename ~Jycar 1300 x 29.
While butadiene polymer and butadlene/
acrylonitrile copolymers have been taught as suitable elastomers for use in this invention, other elastomers such as polychloroprene, polyisobutylene, polyisoprene and acrylic based elastomers may be used, as long as they possess the desired reactive functionality and physical li~itations described above. The selection of suitable reactive liquid elastomers for use in this composition would be well within the capability of one skilled in the art.
As would be apparent to one skilled in the art, mixtures of suitable liquid reactive elastomers may also be used in the composition of the subject invention.

Petroleum Sulfonate Complex Dispersion The petroleum sulfonate complex has the general formula:
2~ ~ _ R - ~ - O M+
o where R is a petroleum hydrocarbon and~or a mixture of other materials such as olefin, olefin polymer, natural 25 fat5, fatty oils and waxes. The cation M+ is generally aod~um, calcium, barium, or magnesium. Sulfonate complexes may be obtained by sul~onating various petroleum fraction~
or their mixtures with sulfuric acid, chlorosulfonlc acid, ~ulfur trioxide and. their mixture~. The petroleum hydrocarbons may be aliphatic, cyclic and/or aromatic.

~7233 One such petroleum sulfonate complex may be produced, for example, by treating a mineral oil (having a Saybolt Uni-versal viscosity at about 39C of from about 400 to 5~0 seconds) with fuming sulfuric acid, preferably in small increments. ~fter a calculated amount of sulfuric acid has been added to the oil, the sludge which forms is removed and the acid-treated oil containing dissolved oil-soluble sulfuric acid is neutralized with a solution of sodium hydroxide. The aqueous alkali solution is removed from the mixture and the sodium salts of petroleum sulfonic acid extracted with alcohol, the alcohol layer containing the sulfonates can be removed by distillation or by any other suitable means. The preparation of petroleum sulfon-ates is well known in the literature and such teachings ca~ be found in U.S. Patents 2,395,713; 2,413,199; 2,414,773;
2,416,397; and if desired the petroleum sulfonates may be purified by means disclosed in U.S. Patents 2,236,993;
2,334,532; 2,357,866; 2,368,452 and 2,406,703. For ease of incorporating the metal salt of the sulfonate complex (which is a very hard solid) into the composition, it is employed dispersed in a non-volatile oil. Suitable oils for use herein have a boiling point above about 230C, e.g. mineral lubricating oils and synthetic lubricating oils. Commercially available dispersions of the petroleum sulfonate complex in oil are available~ for example, from Witco Chemical Corporation, New York, N.Y., under the trade-namP of SACI* (Severe Atmospheric Corrosion Inhibitor).
Examples of such SACI materials which may be employed in the subject composition includes, but is not limited to, CI-51 and SACI ~00-A. Alox Corporation, Niagara Falls, N.Y., also supplies petroleum sulfonate dispersions useful as corrosion inhibitors.

* - Trademark 7;~3 Suitable sulonate complex dispersions for use in th~s invention are those wherein the sulfonate complex comprises between about 30 and about 80 weight percent of the dispersion. More preferably the sulfonate complex comprises between about 50 and about 70 weight percent, most preferably about 50 weight percent of the dispersion employed in the composition of this invention. It can be seen from the limitations of the composition relative the dispersion, that between about 15 and about 6~ part of sulfonate complex will be present in 100 parts composition consisting of adduct, microcrystalline wax and dl~persion.
~owever, it has been found that for optlmal composl~ion properties~ the part~ o dl~per~ion and 1t~ ~ul~on~t~
complex percentage be chosen (from within that taught) so as to provlde between about 25 and about 40 part sulfonate complex (per 100 parts of composition a~ taught above).
Preferably, the sulfonate is a calcium or magnesium ~ulfonate.

Microcrystalline Wax ~ax has been used extensively in hot melt formulations with the prime function of reducing the melt viscosity of a hot melt blend. It is also quite common to include wax in corrosion resistant coating because of the excellent moisture barrier properties. The waxes used in hot melt compositions may be classified into two major categories, paraffin waxes and microcrystalline waxes.
Paraffin waxes are composed of mostly straight chain a~d a few branched or cyclic hydrocarbons. The ~traight chaln hydrocarbon in parafin waxes facilitate the growth of large crystalline regions. I~ is the lack of molecular chain between the crystalline regions which causes the low cohesive strength oE paraffin wax. This in turn i~
teflected in the poorer adhesive and cohesive propertie~ of ~7~Z3~

hot melt compositions containing paraffin wax. Micro-crystalline wa~es have much ~ewer straight chain and many more branched and cyclic groups than paraffin waxes. These waxes, therefore, are usually more flexible and generally softer than a comparable paraffin wax. Microcrystalline waxes also have moderate adhesion and cohesion and con-sequently will form fairly good heat seals.
Any microcrystallin~ wax could be suitably used in the composition of ~his invention. It is known in the art that microcrystalline waxes, as compared to waxes in general, have a relatively narrow melting point range.
Particularly preferred among the many microcrystalline waxes suitable for use in the composition of the subject invention are those having melting points between about 65C and 8~C. Microcrystalline waxes are readily commer-cially available, for example, from Witco Chemical Corpora-tion, New York, N.Y. under the tradename Multi Wax*, e.g., ML-445, 110-X, etc. Selection of the particular micro-crystalline most suitable for use in an embodiment of the subject invention composition would be well within the skill of one in the art.
As would be apparent to one skilled in the art, suitable mixtures of microcrystalline waxes may also be employed in the subject composition.
OEtional Components Including Pigments, Fillers, and Diluent -Oils In addition to the above discussed components, other materials may optionally be included in the hot melt corrosion preventative composition of this invention. When included, these materials comprise additionally between about 0 and about 20 parts by weight, i.e., in addition to the 100 parts by weight of composition consisting of epoxy resin elastomer adduct mixture, microcrystalline wax and sulfonate dispersion. Examples of such materials include * - Trademark pigments, Elame retardants, antioxidants, and nonvolatile dlluent oll. The preferred pigments for the composition a~e aluminum flakes or carbon black. Flame retardants used to retard the flammability of the coating materials, include alumina trihydrate, and phosphorus contain1ng compounds. Thixotropic agents used to control the flow characteristics of the corrosion preventative composition include such mate~ials as fumed silica and fumed alumina.
~hile nonvolatile diluent oil has been used as the dispersing medium for the sulfonate, additional diluent oil may be included in the composition in order to lmprove the wetting of the substrate during application or to facilitate application by reducing viscosity a~, for example,during spray application. A wide range of such nonvolatile diluent oils are available for use in the subject composition. Suitable oils have a boiling point above about 230C and include, but are not limited to, such oils as mineral lubricating oils and synthetic lubricating oils. Other such optional components which may be included in this composition are well known to one skilled in the art.
The invention will be further understood by referring to the following detailed examples. It should be understood that the specific examples are presented by way of illustration and not by way of limitation. Unless otherwise specified, all references to "partsH is intended to mean parts by weight.

~87;~

Exarnple 1 Parts by Weiqht Carboxyl-termina~ed 8utadiene 10 `
(Hycar 200~ ~ 165; carboxy eq. wt. 2000) Epoxy Resin 3 (~pon 828; epoxide eq. wt 175-210) Mlcrocrystalline Wax (M.P. 75-82C) 13 (Mul~i Wax ML-445)*

Petroleum sulfonate dispecsion ~4 (in 50% non-volatile oil; CI-51)**

In a mixing tank equipped with a high shear stirrer and heatin~ element, carboxyl-terminated butadiene polymer was charged and heated to 100-110C. With the temperature kept at 100-110C and the stirring maintained, lS epoxy resin was added and the reaction was continued for 20 minutes, Then, while maintaining tbe temperature, the microcrystalline wax was blended into the adduct to orm a homogeneous mixture. In a separate mixlng tank, the petroleum sulfonate dispersion was heated to about 100-110C. Then the adduct mixture microcrystalline wax was added to this petroleum sulfonate with control stirrlng and while maintaining elevated temperatures until a unifoem compo~ition is obtained. This composition is li~ht brown in color and a rubber-like, non-fluid gel at ambient temperature. The composition thus obtained was charged into a Nelson hot melt unit (Model HM-Xl~ and sprayed at *Available from Witco Chemical Corp., New York, N.Y
~* A calcium sulfonate available ~rom Wi~co Chemical Corp., N~w York, N.Y,.

about 135C to an oily steel panel to give a uniform, firm slightly tacky coating. A panel, which was coated with this composition to a film thickness of between 8 to 10 mils and then the coating scribed with a fine line to the bare metal! was placed in salt spray test. The salt spray test was run with 5-~ salt solution at about 35C. After exposure in the salt og for 1000 hours, the coated panel showed no evidence of corrosion over the substrate surface and no corrosion creepage from the line scribed to bare metal.
~ Example 2 The same composition and procedure as Example 1 were repeated except that 1 part of aluminum pigment~
2 parts of thixotropic agent (Cab-O-Sil* PTG, available from Cabot Corp. Tuscola, Illinois) and 10 parts of diluent oil (Sunpar* 2280, available from Sun Oil Corp. Radnor, Pennsylvania) were blended into the petroleum sulfonate dispersion prior to combination with the adduct wax. The composition is gray in color and more thixotropic than the finished composition of Example 1. ~fter ~eing exposed to ~he salt spray test for 1000 hours, the coated panel did not show any corrosion or corrosion creepa~e.

* - Trademarks 1~1L8~723~

-- lg --Ing~ Parts by We ig h t Carboxyl-terminated butadiene Polymer lO
(Hycar 2000 x 165; carboxyl eq. wt. 2000) 5 Epoxy Resin (Epon lOOl; epoxide eq. wt. 5 450-~50) ~icrocryqtalline Wax (M. P. 75-82C~ 15 (Multi Wax - ML 445) Petroleum sulonate dispersion 70 ~in 50% non-volatile oil CI-51) The same procedure as in Example 1 was rep~ated.
- After salt spray testing as in Example l, the coated panel did not 3how any corrosion or corrosion c~eepage.

Example 4 Ingredients Parts by Weight Carboxyl terminated butadiene 12 polymer tHycar 1300 x 9; carboxyl equivalent wt. 1500) Epoxy Resin (Epon 1002; epoxide 13 equivalent weight 600~700) Microcrystalline wax tM.P. 75-82C) 25 ~MUlti Wax ML-445~

Petroleum sulfonate dispersion 50.
~n.50~ non-volatile. oil: CI-51) 33 ~ t ~ he same procedure as Example l was repeated except 15 part~ of diluent oil ~Sunpar 2280, av~ilable from Sun Oil Co.Radnar, Penn.) was added to the finished composition and then was mixed uniformally. The coated panels showed no evidence of corrosion aEter l000 hours in salt spray testO

~xample 5 Ingredients iarts by Weight .. . . .
Carboxyl-terminated butadiene 8 polymer (Hycar 1300 x 9; carboxyl equivalent welght 1500) Epoxy Resin (Araldite 6060, epoxide 5 e~uivalent weight 385-500) Microcrystalline wax (M~P. 75-82C) 12 (Multi wax ML-445) Petroleum sulfonate dispersion 75 (in 50% non-volatile oil CI-Sl) The same procedure as Example l was repaated.
The coated panels did not show any corrosion or corrosion creepage after 1000 hours in salt spray test.

Example _6 In~g~redients Part~ by Weight Carboxyl-terminated butadiene /acrylo- 20 nitrile copolymer (Hyca.r 1300 x 15;
5 carboxyl eq. wt. 2000) Epox~ resin (Araldite CY~79 epoxide 3 eq. wt. 131-14~) Microcrystalline wax (M.P. 65-68C)12 _ 13 (Multi wax 110 X)*

Petroleum sulfonate dispersion 65 (in 50~ non-volatile oil CI-51) The same procedure as Example 1 was repeated. The coated panels showed no evidence of corrosion or creepage a~ter 1000 hours in salt spray test.
*Available from Witco Chemical Corp., New York, N.Y.

1~137Z31~ ~

Example 7 ~ng~edients Parts by Weiqht Carboxyl-terminated butadiene polymer 10 (Hycar 2000 x lSS; carboxyl eq. wt. 2000) .
5 Epon resin (Ciba-Geigy ECN 1280j epoxide 3 eq. wt. 230) Microcrystalline wax ~M.P. 65 68C)20 - 10 ~Multi Wax llO-X) Pe~roleum sulfonate dispersion 67 (in 50% non-volatile oil; CI-51) The same procedure as Example 1 was repeated. The coated panels did not show any corrosion or corrosion 15 creepage after 1000 hours in salt spray test.

Example 8 In~redients Parts b~ Welqht Carboxyl-terminated butadiene polymer 10 ~Hycar 2000 ~ 165; carboxy eg. wt.
2000) Epoxy resins ~Epon 828; epoxide ey. wt. 2.0 175-210) (Ciba-Geigy ECN 1280; epoxide eg. wt. 230) 1.5 ~icrocrystalline wax (M.P. 65-6HC)23.5 25 (Multi Wax llO-X) 2;33~ ~ t Petroleum sulfonate dispersion 63 (in S0~ non-volatile oil; CI-51) The procedure as in Example 1 was repeated except that a mixture of epoxy resins wa~ used ln this composition. The coating showed excellent corrosion resistance in calt spray test.

Example 9 _ gredients Parts by wei~ht . Amino~terminated butadiene acrylo- 12 nitrile copolymer (Hycar 1300 x 21; amine . wt. 1200) Epoxy resin (Araldite CY-179; epoxide 3 eq~ wt. 131-143) Microcrystalline wax tM.P. 65-68C) 25 _ 15 (Multi Wax llO-X) Petroleum sulfonate dispersion 60 (in 50% non-volatile oil, CI-51) In this Example, the procedure of Example 1 was followed with the materials above except that the reaction 20 temperature was kept at 80-90C (instead of 100-110C as in previous examples). This composition also showed - excellent corrosion resistance in salt ~pray test.

2;~
2~ -~e~ .

Xn~redients Parts by Weight Amino terminated butadiene acrylo- 9 nltrile copolymer (Hycar 1300 x 21; amine eq. wt. 1200) Epoxy resin (Epon 1001; epoxide eq. wt.10 450-550) Microcrystalline wax (M.P. 65-~8C) 21 _ . ~Multi Wax 110 - X) 10 Petroleum sulfonate dispersion 70 (in 50% non-volatile oil; CI-51) The same procedure as Example 1 was repeated. The coated panels did not show any corrosion or corrosion creepage after 1000 hours in salt spray test.

xample ll Parts b~y-weiqht ~ydroxy terminated butadiene acrylo- 20 nitrile copolymer (Hycar 1300 x 29;
Hydroxy eq. wt. 2000) Epoxy resin (Araldite CY~179; epoxide 3 eq. wt. 131-1~3) ~icrocrystalline wax (M.P. 75-82C) 20 (Multi Wax ML-445) Petroleum sulfonate dispersion 57 (60~ ~ulfonate in non-volatile oil;
available from Witco Chemical Corp.) In this example, the liquid elastomer was first heated to 150-160C. Then the epoxy resin was added and the reaction was continued at 150-160~C for 1~ hours.
Hicrocrystalline wax was then blended in. In separate 10 mixing tank, petroleum sulfonate was heated to 100-110C
and the adduct and microcrystalline wax mixture were blended in to obtain a uniform compsition.
The composition was applied to a steel panel as in Example 1. After being exposed to salt spray te~t for 1000 hours, the panel did not show any corrosion or corrosion creepage:

Example 12 In~ dients Parts by Weight Carboxyl terminated butadiene polymer 8 (Hycar 1300 x 9; carboxyl eq. wt. 15001 Epoxy re~in ~Araldite 6060, epoxide 5 (e~. wt. 38S~500) - ~icrocrystalline wax ~M.P. 75Q-82C~ 1 (~ultl Wax ML-445) Petroleum sulfona~e dispersion 77 (35% sulfonate in non-volatile oil, avallable from Witco Chemical Corp.) ~ composition, was made from the above ingredients using the procedure of Example S. After applying this composition to a metal panel~ and subjecting the coated panel to salt spray test, the coated panel did not show any corrosion. . _.

Example 13 10 ~ Ingredientq Parts by we~ht( Epoxy resin (Epon lOOl; epoxide eq. wt. 25 450-550) Mlc~ocrystalline wax (M.P. 75-82C) 15 (Multi Wax ML-4~5) 15 Petroleum sulfonate dispersion 60 ~CX-51; in 50% non-volatile oil) In this example, no liquid reactive elastomer was used. The epoxy resin and the petroleum ~ulfonate dispersion were heated at 135~C with stirring for 2~ hours.
After the stirring was stopped, phase separation was ob~erved. After cooling down to room temperature, th~
mlxture was found to be not homogeneous.

7~

Example 14 Ingredients Parts by Weight Carboxyl terminated butadiene polymer 25 (Hycar 2000 ~ 165, carboxyl eq. wt. 2000) Microcrystalline wax (M.P. 65-68C) 15 (Multi Wax llO-X) Petroleum sulfonate dispersion 65 (CI-51 in 50% non-volatile oil) 10 In this example, liquid reactive elastomer and petroleum sulfonate dispersion were mixed at 135C for 2~ hours. A uniform, syrup type mixture was obtained.
This composition was unable to be applied as a coating ma~erial because it flows at ambient temperatures.
15 The foregoing examples are merely illustrative of the practice of this invention and those skilled in the art will readily recognize that modifications and varia-tions may be made in these examples without departing from the scope of this invention as set forth in the appended claims.
It will be obvious from the foregoing disclosure that this invention has industrial applicability to metal surfaces in need of an adhesive corrosion preven~ative coating in particular those of motor vehicles and provides a coating composition which such outstanding properties whach is hot melt sp~ayable.

Claims (15)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A hot melt corrosion preventative composition, characterized in that said composition comprises:
(1). between about 10 and about 25 parts by weight of an epoxy resin-elastomer adduct mixture formed by reacting:
(a) epoxy resin (i) having a number average molecular weight (Mn) between about 150 and about 2000, and (ii)having two or more reactive epoxide groups per molecule; and (b) reactive elastomer (i) having a number average molecular weight (Mn) of between about 2000 and about 10,000, (ii) having reactive functionality capable of reacting with the epoxide group of said epoxy resin, and (iii) being liguid at 20-25°C;
wherein (a) and (b) are combined in amounts providing between about 1.8 and about 3.0 epoxide groups of said resin for each said reactive functionality of said elastomer and reacted so as to react at least about 80% of said reactive functionality of said elastomer;
(2) between about 10 and about 25 parts by weight of microcrystalline wax; and (3) between about 50 and about 80 parts by weight of a dispersion of a petroleum sulfonate complex in nonvolatile diluent oil, (i) said complex comprising between about 30 and about 80 weight percent of said dispersion and (ii) said oil having a boiling point above about 230°C, wherein the total weight of said (1), (2) and (3) is 100 parts by weight.

2. A sprayable hot melt corrosion preventative com-position according to claim 1, wherein said epoxy resin is diepoxide resin having a number average molecular weight (Mn) of between about 200 and about 1500.

3. A sprayable hot melt corrosion preventative compo-sition according to claim 2, wherein said diepoxide resin is the reaction product of epichlorohydrin and bisphenol A.

4. A sprayable hot melt corrosion preventative com-position according to claim 1, wherein said elastomer has a number average molecular weight (Mn) of between about 2,000 and about 5,000.

5. A sprayable hot melt corrosion preventative compo-sition according to claim 1 or 4, wherein said reactive functionality of said elastomer is selected from the group consisting of (i) carboxyl groups, (ii) amino groups, (iii) hydroxyl groups and (iv) mixtures thereof.

6. A sprayable hot melt corrosion preventative compo-sition according to claim 1 or 4, wherein said reactive functionality of said elastomer is selected from the group consisting of (i) carboxyl groups, (ii) amino groups, (iii) hydroxyl groups and (iv) mixtures thereof, and said elastomer contains about two of said reactive functionality per molecule.

7. A sprayable hot melt corrosion preventative compo-sition according to claim 1, wherein said adduct mixture is formed by reacting said epoxy resin and said elastomer in amounts providing between about 1.8 and 2.5 epoxide groups of said resin for each reactive functionality of said elastomer.

8. A sprayable hot melt corrosion preventative composition according to claim 7, wherein slid adduct mixture is formed by reacting said epoxy resin and said elastomer in amounts providing between about 2.0 and about 2.5 epoxide groups of said resin for each reactive functionality of said elastomer.

9. a sprayable hot melt corrosion preventative composition according to claims 1 or 8, wherein said epoxy resin and said elastomer are reacted so as to react at least about 90% of said reactive functionality of said elastomer.

10. A sprayable hot melt corrosion preventative composition according to claim 1, wherein said petroleum sulfonate complex comprises between about 50 and about 70 weight percent of said dispersion.

11. A sprayable hot melt corrosion preventative composition according to claim 1, wherein said dispersion provides between about 25 and 40 parts by weight of said petroleum sulfonate complex.

12. A sprayable hot melt corrosion preventative composition according to claim 1, wherein said sulfonate complex is selected from the group consisting of sulfonate complexes of magnesium, calcium, barium, sodium and mixtures thereof.

13. A sprayable hot melt corrosion preventative composition according to claim 1 further comprising up to about 20 parts by weight fillers, pigments, diluent oil and mixtures thereof.

14. A sprayable hot melt corrosion preventative composition which, exclusive of pigments, filler and other non-reactive components, is characterized in consisting essentially of:
(1) between about 10 and about 25 parts by weight of an epoxy resin elastomer adduct mixture formed by reacting:
(a) epoxy resin (i) having a number average molecular weight (Mn) of between about 150 and about 2000 and (ii) being the reaction product of epichlorohydrin and bisphenol A;
(b) reactive elastomer (i) having a number average molecular weight (Mn) of between about 2000 and about 10,000, (ii) having about two carboxyl functionalities per molecule, and (iii) being liquid at 20°-25°C;
wherein (a) and (b) are combined in amounts providing between about 1.8 and about 3.0 epoxide groups of said resin for each carboxyl functionality of said elastomer and reacted so as to react at least about 80% of said carboxyl functionalities of said elastomer.
(2). between about 10 and about 25 parts by weight of microcrystalline wax; and (3). between about 50 and about 80 parts by weight of a dispersion of a petroleum sulfonate complex in nonvolatile diluent oil, (i) said complex comprising between about 50 and about 70 weight percent of said dispersion and (ii) said oil having a boiling point above about 230°C, wherein the total weight of said (1), (2) and (3) is 100 parts by weight.

15. A method for making a hot melt corrosion preventive composition characterized in that said composition is made by:
providing between about 10 and about 25 parts by weight of an epoxy resin elastomer adduct mixture which is maintained at an elevated temperature;

homogeneously blending into said adduct mixture between about 10 and about 25 parts by weight microcrystalline wax while maintaining said elevated temperature;

heating between about 50 and about 80 parts by weight of a dispersion comprising sulfonate complex in diluent oil to an elevated temperature;
and adding the homogeneous adduct-wax mixture with stirring into said dispersion while maintaining said elevated temperatures thereof so as to form a homogeneous corrosion preventative composition, wherein said epoxy resin elastomer adduct mixture is formed by reacting:
(a) epoxy resin having (1) a number average molecular weight (?n) of between about 150 and about 2000, and (ii) having two or more epoxide groups per molecule; and (b) reactive elastomer (i) having a number average molecular weight (?n) of between about 2,000 and about 10,000, (ii) having reactive functionality capable of reacting with the epoxide groups of said epoxy resin, and (iii) being liquid at 20-25°C;

- 15 contd -wherein (a) and (b) are combined in amount providing between about 1.8 and about 3.0 epoxide groups of said resin for each said reactive functionality of said elastomer and reacted so as to react at least about 80% of said reactive functionality of said elastomer and, wherein said dispersion comprises a petroleum sulfonate complex in nonvolatile diluent oil, (i) said complex comprising between about 30 and about 80 weight percent of said dispersion and (ii) said oil having a boiling point above about 230°C, and wherein the total weight of said adduct mixture, said microcrystalline wax, and said dispersion is 100 parts by weight.