WO1995019379A1

WO1995019379A1 - Body putty resin

Info

Publication number: WO1995019379A1
Application number: PCT/US1995/000330
Authority: WO
Inventors: Dan Alan Ruggeberg
Original assignee: Reichhold Chemicals, Inc.
Priority date: 1994-01-13
Filing date: 1995-01-12
Publication date: 1995-07-20
Also published as: EP0739369A1; CA2181191A1; AU1677795A; MX9602790A

Abstract

A body putty resin composition of the present invention comprises 20 to 50 weight percent of a reactive component which becomes an integral part of the composition on curing, and 50 to 80 weight percent of a polyester formed from an α,β-unsaturated dibasic acid and/or anhydride, one or more of a polyhydric alcohol, a combination of a polyhydric alcohol and dicyclopentadiene, or dicyclopentadienyl alcohol, and optionally a saturated dibasic acid and/or anhydride, wherein the ratio of total number of equivalents of hydroxy to total number of equivalents of acid is about 0.5 to 1.2 and wherein from about 15 to 60 percent of the α,β-unsaturated dibasic acid and/or anhydride is available to react with the reactive component.

Description

BODY PUTTY RESIN

Related Application

The present application is a continuation- in-part of U.S. Serial No. 08/182,467, filed January 13, 1994, the disclosure of which is incorporated herein by reference in its entirety. Field and Background of the Invention

This invention relates to a body putty resin composition. The body putty resin composition of the present invention exhibits adherence to metallic surfaces such as zinc-coated (galvanized) metals, and thus is particularly adapted for use in repairing automobile bodies. Dents, gouges and other surface irregularities of automobile body parts are routinely fixed or repaired with either metallic solders or various plastic materials. Metallic solders are disfavored because application thereof is difficult and requires a great deal of skill. Exemplary plastic materials are a putty composed of a thermoset resin (e.g., an unsaturated polyester resin or an epoxy vinyl ester), fillers, promoters, catalysts and other additives. The putty is allowed to harden and is subsequently sanded to conform to the desired contour of the automobile body part. Standard body putty has successfully been used to repair damaged steel surfaces of automobile bodies. However, rust and corrosion have increasingly become major problems for automobiles whose bodies are manufactured from mild steel (i.e. , low carbon steel). In order to mii-imize corrosion, the automobile industry is replacing mild steel with zinc-coated (galvanized) steel. It has been found that standard body putties that are typically used for mild steel have poor adhesion to galvanized steel. Thus, an urgent need exists for a means of improving the adhesion of automobile body putties to galvanized steel.

For example, U.S. Patent No. 5,169,723 to Forster proposes that a chemically etched surface of galvanized steel provides improved adhesion for a polyester resin based automobile body putty. The etching solution comprises a metal salt that is more electropositive than zinc. The putty is applied to the etched surface and after curing is sanded to conform to the desired contour of the automobile body.

U.S. Patent No. 4,525,427 to Bayha et al. relates to a polyester composition capable of forming a thin film that adheres to metal and plastic substrates, such as steel, and are particularly useful in repairing automobile bodies. These compositions are referred to as "body putty primers" . Bayha further proposes that the metallic surface may also be chemically etched to maximize adhesion of surfacing materials to the metal surface. However, body shops tend to want to avoid compromising the galvanized surface by sanding into the metal or etching the surface in view of car-maker warranty limitations, especially as it includes another labor step. Other compositions and methods for repairing automobile body parts are proposed in, for example, U.S. Patent Nos. 4,531,275 to Kelly, 4,732,633 to Pokorny, and 4,308,118 to Dudgeon.

Despite the general availability of various plastic materials and methods for repairing automobile body parts, there continues to be a need for improvements in body putty resin compositions, and particularly in the adhesion thereof to zinc-coated (galvanized) metal. Moreover, such a body putty resin composition must be capable of providing a coating which is flexible. A body putty which is more flexible will be less likely to be dislodged from the automobile due to cohesive failure. Summary of the Invention

With the foregoing in mind, it is an object of the invention to provide a body putty resin composition which has improved adherence to metal surfaces and particularly zinc-coated (galvanized) metal surfaces. It is a feature of the present invention to provide a flexible body putty resin composition.

It is another feature of the present invention to provide a body putty resin composition which provides a surface with improved sandability.

It is another feature of the present invention to provide a body putty resin composition which does not require the galvanized metal surface to be compromised to effect adhesion of the resin composition to the metal surface.

These and other objects, features and advantages are provided by the body putty resin composition of the present invention which comprises 20 to 50 weight percent of a reactive component which becomes an integral part of the composition on curing, and 50 to 80 weight percent of a polyester formed from an α, 3-unsaturated dibasic acid and/or anhydride, one or more of a polyhydric alcohol, a combination of a polyhydric alcohol and dicyclopentadiene, or dicyclopentadienyl alcohol, and optionally a saturated dibasic acid and/or anhydride, wherein the ratio of total number of equivalents of hydroxy to total number of equivalents of acid is about 0.5 to 1.2, and preferably 0.8 to 1.2, and wherein from about 15 to 60 percent of the c.,j8-unsaturated dibasic acid and/or anhydride is available to react with the reactive component.

Typically, the resin composition comprises 50 to 80 weight percent of polyester formed from about 30 to 40 weight percent of an o.,/3-unsaturated diacid and/or anhydride, 30 to 40 weight percent of dicyclopentadiene, and 20 to 30 weight percent of a polyhydric alcohol; and 20 to 50 weight percent of a reactive component which becomes an integral part of the composition on curing. The body putty composition can include fillers, pigments, thixotropic additives, reinforcing materials, and various other conventional additives. In another embodiment, the present invention provides a body putty resin composition comprising 20 to 50 weight percent of a reactive component which becomes an integral part of the composition on curing; and 50 to 80 weight percent of a polyester formed from an a,β -unsaturated dibasic acid and/or anhydride, a polyhydric alcohol and dicyclopentadiene or derivative thereof, and optionally a saturated dibasic and/or anhydride, wherein a nadic moiety is formed between the c.,/3 -unsaturated dibasic acid and/or anhydride and cyclopentadiene formed from dicyclopentadiene or derivative thereof, wherein the ratio of total number of equivalents of hydroxy to total number of equivalents of acid is about 0.5 to 1.2, and preferably 0.8 to 1.2, and wherein from about 15 to 60 percent of the o.,/3-unsaturated dibasic acid and/or anhydride is available to react with the reactive component. The present invention also provides a galvanized metal surface adhered to which is a body putty resin composition comprising 20 to 50 weight percent of a reactive component which becomes an integral part of the composition on curing, and 50 to 80 weight percent of a polyester formed from an c-, 3-unsaturated dibasic acid and/or anhydride, one or more of a polyhydric alcohol, a combination of a polyhydric alcohol and dicyclopentadiene, or dicyclopentadienyl alcohol, and optionally a saturated dibasic acid and/or anhydride, wherein the ratio of total number of equivalents of hydroxy to total number of equivalents of acid is about 0.5 to 1.2, and preferably 0.8 to 1.2, and wherein from about 15 to 60 percent of the o:, 3-unsaturated dibasic acid and/or anhydride is available to react with the reactive component.

The term "galvanized" is intended to relate to zinc-coated metal. Galvanized metal is commonly used to protect rust-prone metal such as the steel used in automobile bodies. The surface of galvanized metal used in the automobile industry typically is coated with zinc or a zinc alloy to about 50 to 70g/m². It is this type galvanized metal to which the present invention is particularly directed, although it is contemplated to use the body putty resin composition of the present invention with other metallic surfaces.

The present invention also provides a method of repairing a damaged galvanized metal surface. The method comprises catalyzing the curing of one of the above-described body putty resin compositions; applying the curing body putty resin composition to the damaged metal surface; and subjecting the damaged metal surface having the body putty applied thereto to conditions sufficient to cure the body putty and to finish the damaged metal surface.

Brief Description of the Drawings

Figure 1 is a perspective view of an automobile having a metal surface adhered to which the body putty resin composition of the present invention is being applied.

Figure 2 is a cross-sectional view taken along line 2-2 of Figure 1.

Detailed Description of the Invention

The present invention will now be described more fully hereinafter. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiment set forth herein; rather, this embodiment is provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

In accordance with the present invention, a body putty resin composition has been found having improved adhesion to metal surfaces and particularly galvanized metal surfaces. The body putty resin composition of the present invention also provides a flexible surface when cured and is less likely to be dislodged from the automobile due to cohesive failure. Moreover, the body putty resin composition can be easily sanded in that the dusting is greater, namely, more of the cured resin composition is removed with each sanding.

As summarized above, the body putty resin composition of the present invention comprises 20 to 50 weight percent of a reactive component which becomes an integral part of the composition on curing, and 50 to 80 weight percent of a polyester formed from an o^*,0-unsaturated dibasic acid and/or anhydride, one or more of a polyhydric alcohol, a combination of a polyhydric alcohol and dicyclopentadiene, or dicyclopentadienyl alcohol, and optionally a saturated dibasic acid and/or anhydride, wherein the ratio of total number of equivalents of hydroxy to total number of equivalents of acid is about 0.5 to 1.2, and preferably 0.8 to 1.2, and wherein from about 15 to 60 percent of the c-, 3-unsaturated dibasic acid and/or anhydride is available to react with the reactive component.

In one embodiment, the resin composition comprises 50 to 80 weight percent of polyester formed from about 30 to 40 weight percent of an ,β- unsaturated diacid and/or anhydride, 30 to 40 weight percent of dicyclopentadiene, and 20 to 30 weight percent of a polyhydric alcohol; and 20 to 50 weight percent of a reactive component which becomes an integral part of the composition on curing.

In another embodiment, the body putty resin composition comprises 20 to 50 weight percent of a reactive component which becomes an integral part of the composition on curing; and 50 to 80 weight percent of a polyester formed from an c-, 3-unsaturated dibasic acid and/or anhydride, a polyhydric alcohol and dicyclopentadiene or derivative thereof, and optionally a saturated dibasic and/or anhydride, wherein a nadic moiety is formed between the ,β- unsaturated dibasic acid and/or anhydride and cyclopentadiene formed from dicyclopentadiene or derivative thereof, wherein the ratio of total number of equivalents of hydroxy to total number of equivalents of acid is about 0.5 to 1.2, and preferably 0.8 to 1.2, and wherein from about 15 to 60 percent of the c.,/3-unsaturated dibasic acid and/or anhydride is available to react with the reactive component.

Suitable c.,β-unsaturated dibasic acids include maleic, fiimaric, itaconic, chloromaleic, citraconic, and like acids and/or anhydrides. Maleic acid and maleic anhydride are preferred particularly when the formation of the nadic moiety is desired. The amount of α,/3-unsaturated dibasic acid and/or anhydride available for reaction with the reactive component is believed to be critical to the adhesion of the body putty resin in that the high amount of unsaturated dibasic acid or anhydride results in a high reactivity. The balance of any diacids or anhydrides employed to modify the reactivity and properties of the polyester may be either saturated or of the non-c-,/? -unsaturated type, and may be, for example, phthalic, isophthalic, terephthalic, tetrahydrophthalic, or tetrachlorophthalic acid, methylenetetrahydrophthalic acid (nadic acid), hexachloroendo-methylenetetrahydrophthalic acid or low-molecular weight aliphatic dicarboxylic acids, such as succinic, adipic or diglycolic acid, or their anhydrides.

The resulting resin composition can have an end-capped dicyclopentadiene moiety or can have a nadic moiety. The term "nadic moiety" relates to the adduct formed between the c., -»-unsaturated dibasic acid and/or anhydride (e.g. , maleic anhydride) and cyclopentadiene derived from dicyclopentadiene. In operation, one mole of dicyclopentadiene cracks to produce two moles of cyclopentadiene which in turn add across the double bonds of two moles of, for example, maleic acid derived from the ring opening of maleic anhydride. Another option is to use nadic acid or anhydride, and react it directly with the glycol. This is contrasted to an "end-capping dicyclopentadiene moiety" wherein during processing the elevated temperatures of the reaction mixture are high enough to obtain a maleic anhydride- dicyclopentadiene adduct but low enough to avoid cracking dicyclopentadiene, and to avoid maleic acid isomerizing to fumaric acid. Typically, the cracking temperature is about 140°C or higher.

Suitable polyhydric alcohols include ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, 1,3-butanediol, 1 ,4-butanediol, 1,3 hexanediol, neopentyl glycol, methyl-pentanediol, 1,3-butylene glycol, 1,6- hexanediol, neopentyl glycol, ethylene oxide adduct of bisphenol, and propylene oxide adduct of bisphenol. The use of dicyclopentadiene in forming unsaturated polyester is well known (see, for example, U.S. Patent No. 3,347,804 to Zimmerman, the disclosure of which is incorporated herein by reference in its entirety). Derivatives of dicyclopentadiene can also be used such as dicyclopentadiene alcohols if an end-capping moiety is desired. It is noted that the ratio of total number of equivalents of hydroxy to total number of equivalents of acid is preferably 0.8 to 1.2 when maleic acid is not used and 0.5 to 1.2 when maleic acid is used.

The phrase "reactive component which becomes an integral part" is intended to relate to a component that during curing (polymerization) of the polyester becomes crosslinked into the polymer. This is to be contrasted to the use of solvents that are merely added as processing aids such as to dilute the resin composition so that the resin can be applied as a coating such as described in U.S. Patent No. 4,525,427 to Bayha et al. or the use of water to form an emulsion such as described in U.S. Patent Nos. 4,447,577 and 4,551,489 to Bayha. The solvents in these patents are intended to be flashed off and do not become an integral part of the polyester resin. Additionally, it is noted that the resins of Bayha are end-capped dicyclopentadiene resins

Suitable reactive components include acrylates such as methylmethacrylate, styrene, vinyl toluene, divinylbenzene, diallyl phthalate, and styrene-derivatives such as chlorostyrene. The body putty composition can include a tertiary amine promoter.

Nonhydroxy functional tertiary amines include dimethylaniline, diethylaniline, and dimethyl-p-toluidine, and are typically mixed into the resin composition. Hydroxy-functional tertiary amine promoters include -tolyl diethanolamine or m-tolyl diethanolamine, and may be incorporated into the polyester backbone via esterification with acid end groups or can be simply mixed into the resin composition.

The curing of the body putty resin composition can be catalyzed by free radical peroxide initiators such as benzoyl peroxide, methyl ethyl ketone peroxide, t-butyl hydroperoxide, t-butyl perbenzoate, and others known in the art. Those skilled in the art will recognize that certain peroxide initiators will require that a metallic salt such as cobalt octoate/napthenate be blended into the resin to effect cure. Various types and concentrations of quinone (and other) types of inhibitors may be used to obtain the required gel time with free radical peroxide initiators. The body putty resin composition can further include fillers, pigments and dyes, stabilizers, thixotropic additives and various other additives. Suitable fillers include calcium carbonate, clay, talc, alumina hydrate, kaolin, silica sand, mica, and the like. Preferably, the amount of filler in the resin composition ranges from about 40 to 70 percent by weight. Suitable thixotropic agents include activated silicas, castor oil derivatives, activated clay thixotropies, and the like. Reinforcing materials can also be included. A wide variety of reinforcing materials are available and include glass fibers, glass microballoons, carbon fibers, sisal fibers, Kevlar^® fibers, asbestos fibers, cotton fibers, steel fibers, and the like. In operation, the body putty resin composition is formed by reacting the individual constituents together using known techniques. The resin composition is prepared in a reactor vessel equipped with a mechanical stirrer, a condenser and an inert gas (e.g. , nitrogen) inlet. The order of reaction will vary depending whether an end-capping dicyclopentadiene moiety or a nadic moiety is desired. For example, if an end-capping moiety is desired, dicyclopentadiene or derivatives thereof and optional water if an anhydride form of the unsaturated dibasic acid is used, are added to the vessel followed by adding the c-, 3-unsaturated dibasic acid and/or anhydride in a controlled manner such that the heat of the exotherm does not elevate the batch temperature beyond about 125 °C. The temperature is maintained at about 125 °C for about 2 hours. The polyhydric alcohol and optional tertiary amine promoter are added before raising the temperature to about 205 °C. The batch is cooled and the inhibitor and reactive component are added. The mixture is then cooled to about 25 °C. The curing of the curable body putty resin composition is catalyzed using, for example, using a free radical peroxide initiator.

If a nadic moiety is desired, the polyhydric alcohol (e.g., diethylene glycol) is added to the vessel in a controlled manner and heated to about 80°C. The c-,j8-unsaturated dibasic acid and/or anhydride is added while limiting the batch temperature to about 130 °C. The vessel is heated to about 210°C. The temperature is cooled to about 170°C and the dicyclopentadiene is added. The batch is held at 170°C for about one hour to crack the cyclopentadiene. The mixture is then cooled to about 25 °C. The curing of the curable body putty resin composition is catalyzed using, for example, using a free radical peroxide initiator. As shown in Figures 1 and 2, the curing body putty resin composition 10 is applied to a damaged metal surface 20 such as an automobile 30 fender. The resin composition is permitted to cure and the damaged metal surface is finished such as by sanding and painting.

A cured body putty made with the body putty resin composition of the present invention provides rapid sandability (less than 20 minutes after catalyzation of putty made with it) and superior adhesion properties permitting the artisan to sand the borders of the cured putty down to a "feathered-edge. " This is the region of disappearing putty thickness grading into the surrounding undamaged metal. Cured putties made with the resin of the present invention cease to be solvent sensitive (an important aspect of adhesion) in the feather- edge region in less than 20 minutes following catalyzation of the putty. In contrast, conventional body putties will remain solvent sensitive in the feather- edge region beyond 18 hours. If the repaired area is painted while still solvent sensitive in the feather-edge region, the paint solvents will dislodge the putty film from the galvanized metal substrate causing peeling. Peeling, in turn, costs the body shop time and labor to rework the area of repair. The putty has improved flexibility particularly when it has a nadic moiety. The more flexible a putty, the less likely it will disengage from the automobile. Additionally, the putty is softer.

The following examples are illustrative of the present invention, and are not to be construed as limiting thereof.

EXAMPLES

Example 1

A resin composition comprising the follow

Composition Moles Wgt % dicyclopentadiene 70 38.0 water 7 0.5 maleic anhydride 100 40.3 7-tolyl diethanolamine 2 1.6 ethylene glycol 77 19.6 The resin composition is prepared in a reactor vessel equipped with a mechanical stirrer, a condenser and a nitrogen gas inlet in the following manner. The dicyclopentadiene and water are added under a nitrogen blanket to the vessel and heated, with stirring, to 95 °C. Maleic anhydride is added in a controlled manner such that the heat of exofherm does not elevate the batch temperature beyond about 125 °C. Following the addition of the maleic anhydride, the batch temperature is maintained at about 125 °C for about two hours. Preparation in this manner maximizes the formation to the maleic- dicyclopentadiene ester. The ethylene glycol and -tolyl diethanolamine are then added before raising the reaction temperature to 205 °C and processing the polymer to its endpoint determined by a Gardner-Holdt viscosity of S-T and acid number 8-15 at 67 percent nonvolatiles in inhibited styrene. The batch is then cooled to 190°C to slow the reaction. The batch is then blended with 50 ppm hydroquinone inhibitor and styrene (reactive component) such that the mixture is maintained below 80 °C and such that the final nonvolatiles content of the mixture is about 65 percent by weight. The mixture is then cooled to 25 °C. The resulting resin when compounded with talc filler and catalyzed with benzoyl peroxide is easily sanded. Example 2

In order to evaluate the addition of no dicyclopentadiene, a resin composition comprising the following is prepared.

Composition Moles Wgt % diethylene glycol 105 49.9 p-tolyl diethanolamine 2 1.7 phthalic anhydride 20 13.3 maleic anhydride 80 35.1

The resin composition is prepared in a reactor vessel equipped as in Example 1. The diethylene glycol and / olyl diethanolamine are added to the vessel, with stirring, under a nitrogen blanket and heated to about 80 °C. Flaked phthalic anhydride is added through a powder funnel over about 20 minutes. The maleic anhydride (molten) is added in four equal portions over a one-hour period to limit the batch temperature (due to exotherm) to about 130°C. The reaction temperature is then raised to 220 °C and the polymer is processed to its endpoint determined by a Gardner-Holdt viscosity of J-K and an acid number of 10-14 at 67 percent nonvolatiles in inhibited styrene. The batch is then cooled to 190°C to slow the reaction. The batch is then blended with 50 ppm hydroquinone inhibitor in styrene (reactive component) such that the mixture is maintained below 80 °C and such that the final nonvolatiles content of the mixture is about 65 percent by weight. The mixture is then cooled to 25 °C.

Example 3

In order to demonstrate the formation of a nadic moiety, a resin composition comprising the following is prepared. Composition Moles Wgt % diethylene glycol 60 28.5 propylene glycol 46 15.7 maleic anhydride 100 44.0 dicyclopentadiene 20 11.8

The resin composition is prepared in a reactor vessel equipped as in Example 1. The diethylene glycol and propylene glycol are added to the vessel under a nitrogen blanket, with stirring, and heated to about 80°C. The maleic anhydride is added in four equal portions over a one-hour period to limit the batch temperature (due to exotherm) to about 130°C. The batch temperature is then raised to 210°C and processed to the point at which the Gardner-Holdt viscosity is about S-T and the acid number of 10-20 at 67 percent nonvolatiles in inhibited styrene. The batch is then cooled to about 170°C. The dicyclopentadiene is now metered into the reactor over a one-hour period. Processing in this manner maximizes formation of the nadic moiety (maleic- cyclopentadiene adduct) as each mole of dicyclopentadiene cracks to produce two moles of cyclopentadiene which in turn add across the double bonds of two moles of maleic anhydride. Following addition of the dicyclopentadiene, the batch is held at 170°C for one hour before cooling to slow the reaction. The batch is then blended with 50 ppm hydroquinone inhibitor and styrene (reactive component) such that the mixture is maintained below 80 °C and such that the final nonvolatiles content of the mixture is about 65 percent by weight. Finally, the batch is cooled to 25 °C. After cooling, 0.6 percent by weight (of polyester plus styrene) of dimethylaniline is blended into the product.

Example 4

A resin composition comprising the following is prepared.

Composition Moles Wgt % maleic anhydride 1.0 40.5 dicyclopentadiene 0.32 18.8 diethylene glycol 0.69 30.2 ethylene glycol 0.41 10.5

The resin composition is prepared according to the procedure outlined in Example 3 above.

Example 5

A resin composition comprising the following is prepared.

Composition Moles Wgt % diethylene glycol 105 50.8 phthalic anhydride 20 13.5 maleic anhydride 80 35.7 The resin composition is prepared in a reactor vessel equipped as in Example 1. The diethylene glycol is added to the vessel under a nitrogen blanket, with stirring, heated to about 80 °C. Flaked phthalic anhydride is added through a powder funnel over about 20 minutes. The maleic anhydride (molten) is then added in four equal portions over a one-hour period to limit the batch temperature (due to exotherm) to about 130°C. The reaction temperature is raised to 220 °C and the polymer is processed to its endpoint determined by a Gardner-Holdt viscosity of about J-K and an acid number of about 10-20 at 67 percent nonvolatiles in inhibited styrene. The batch is then cooled to 190°C to slow the reaction. The batch is then blended with 50 ppm hydroquinone inhibitor in styrene such that the mixture is maintained below 80 °C and such that the final nonvolatiles content of the mixture is about 65 percent by weight. Finally, the batch is cooled to 25 °C. After cooling, 0.5 percent by weight (of polyester plus styrene) of dimethylaniline is blended into the product.

Example 6

A resin composition comprising the following is prepared.

Composition Moles Wgt % diethylene glycol 105 46.5 phthalic anhydride 60 37.1 maleic anhydride 40 16.4

The resin composition is prepared according to the procedure outlined in

Example 5 above.

Comparative Example 1

A resin composition comprising the following is prepared. Composition Moles Wgt % diethylene glycol 105 45.6 phthalic anhydride 70 42.4 maleic anhydride 30 12.0

The resin composition is prepared according to the procedure outlined in Example 5, above. Comparative Example 2

A resin composition comprising the following is prepared.

Composition Moles Wgt % diethylene glycol 105 44.6 phthalic anhydride 80 47.5 maleic anhydride 20 7.9

The resin composition is prepared according to the procedure outlined in Example 5, above.

Putty resins prepared in a manner similar to Comparative Example 2 are typical of the vast majority of resins currently utilized in automobile body putties.

Adhesion Evaluation Procedure

Each resin is adjusted to 500 centipoise viscosity with styrene and also adjusted with inhibitor (i.e., hydroquinone) such that a putty prepared from it would yield a putty gel time of 4 to 6 minutes (at 25 °C) when catalyzed with 2 percent by weight of 50 percent benzoyl peroxide paste. In each case, a ratio of 40 parts resin to 60 parts of talc (i.e. , Vertal-92 from Lomas International) is used.

All putties are catalyzed as described and applied to the substrate (solvent wiped, not sanded) at a thickness of about 1/16". Suitable substrates include automaker certified galvanized metal test panels such as "90E, " "EGA, " "E60," "45E" obtainable from Advanced Coatings Technology, Hillsdale, Michigan. The galvanized coating on these range from pure zinc to zinc alloys which are applied from 50 to 70 g/m². The "GM 90E" type is used as the standard as it is identified as having the greatest zinc content and thus proved to be the most difficult upon which to achieve adhesion.

The putties are checked for adhesion (30 minutes after catalyzation and overnight) by bending the metal panel over the edge of a table to a 90° angle. The cured putty is then chipped away from the creased area of the substrate. If pieces of the putty could be removed leaving no film of putty remaining on the substrate, the sample is considered to have undergone adhesive failure. Cohesive failure is demonstrated when a film of putty remained on the substrate. The samples are considered to have demonstrated true adhesion only if this remaining film was not solvent-sensitive (could not be wiped clean with a solvent soaked rag). The relevance of solvent sensitivity to adhesion is demonstrated in the feather-edge area during the painting phase of the auto repair process as described earlier.

The putty systems appearing in Table I below are identified by the resin prepared in each of the above examples.

Table I

Putty Adhesion @ Adhesion Composition Wet % Maleic 30 Mins. ? Overnight?

Example 1 40.3 YES YES

Example 2 35.1 YES YES

Example 3 44.0 YES YES

Example 5 35.7 YES YES

Example 6 16.4 YES YES

Comparative Example 1 12.0 NO NO

Comparative Example 2 7.9 NO NO

Thus, all putties prepared from resins formulated with greater than 15 percent maleic anhydride by weight demonstrated adhesion to the galvanized metal substrate by the 30 minute mark. Furthermore, allowing putties of Comparative Examples 1 and 2 to cure overnight did not enhance adhesion performance.

Comparative Example 3

A resin composition according to Example 1 of U.S. Patent No. 4,525,427 to Bayha et al. is prepared. This composition is a primer and includes toluene as a solvent. In order to evaluate the composition as a body putty, the resin composition is compounded with talc in a 40/60 ratio. The putty is catalyzed using 2 percent by weight of a 50 percent benzoyl peroxide catalyst. The putty is then applied to a thickness of 1/16 inch to a galvanized metal substrate. It sagged and did not dry for several days. There is no adhesion. Thus, the composition is not useful as body putty resin and must be applied as a thin primer coating.

Comparative Example 4

An end-capped resin composition comprising the following is prepared.

Composition Moles Wgt % maleic anhydride 1.0 40.0 dicyclopentadiene 0.32 18.1 water 0.52 3.7 diethylene glycol 0.69 29.8 ethylene glycol 0.41 10.1 The processing and ttanning procedures used are identical to those described in "Method 2" of U.S. Patent No. 4,525,427 to Bayha et al. In this way an end- capped resin can be prepared and compared to a resin having a nadic moiety (Example 4).

Comparison of Liquid Properties The liquid properties of the Comparative Example 4 and Example 4 are compared.

C Coommppaarraattiivvee

Example 4 Example 4

Weight % styrene 67 67 V Viissccoossiittyy ( (cceennttiippooiissee)) 7 72200 445

SPI gel time (mins) 4.1 5.7

Cure interval 1.7 5.8

Peak exotherm, °F 421 307

The difference in viscosity is due to the difference in chemical structures of the polymers. The differences in SPI gel time, Cure Interval and Peak Exotherm illustrate the lower reactivity of the body putty resin of Example 4. Lower reactivity results in less crosslink density and a more flexible but tough putty.

Comparison of Physical Properties

These resins were compared for physical properties following compounding with body putty fillers to simulate a typical "lightweight" putty formula used in the U.S. market:

Material Weight %

Resin 50

DMA 0.2 Talc 44

TiO₂ 2.4

Fumes Silica 0.6

Glass Microspheres 3

Dimethylaniline (DMA) is a promoter necessary to effect cure with benzoyl peroxide paste (common putty catalyst). TiO₂ is added to lighten the color of putties. Fumed silica provides desired Theological behavior. Glass microspheres lower the putty density.

Both putties are catalyzed with 2% of 50% active benzoyl peroxide catalyst paste, pressed between glass plates set 0.25 inch apart and allowed to cure overnight at ambient temperature. Specimens of each are then cut and tested on an Instron using ASTM procedures for flexural properties. The following results are summarized in Table II:

Table II

Comparative Example 4 Resin Example 4

Barcol hardness 15-17 0

Shore D hardness 100+ 70-75

Flexural Strength, psi 3962 2929

Flexural Modulus, psi x 10^s 6.77 3.42 Flexural Toughness, in. #/in³ 2.19 6.28

Barcol hardness is an index of an higher range than Shore D hardness. Flexural modulus is a measure of relative stiffness. Flexural toughness is a measure of the extent to which a material will absorb energy without fracture. The above data clearly show that cured putty made with the resin having a nadic moiety is much more flexible and softer than that made with the conventional resin exemplified in Bayha et al. , U.S. Patent No. 4,525,427. These properties have critical impact on putty performance and marketplace acceptability. The more flexible a putty is, the less likely it will be dislodged from the automobile. Moreover, the surface can be rapidly sanded.

In the specification and examples, there have been disclosed preferred embodiments of the invention. Although specific terms are employed, they are used in a generic and descriptive sense only and not for the purpose of limitation, the scope of the invention being defined by the following claims.

Claims

CLAEVIS:

1. A curable body putty resin composition suitable for use in repairing metal surfaces, the body putty resin composition comprising:

20 to 50 weight percent of a reactive component which becomes an integral part of the composition on curing, and 50 to 80 weight percent of a polyester formed from an o.,/3-unsaturated dibasic acid and/or anhydride, one or more of a polyhydric alcohol, a combination of a polyhydric alcohol and dicyclopentadiene, or dicyclopentadienyl alcohol, and optionally a saturated dibasic acid and/or anhydride, wherein the ratio of total number of equivalents of hydroxy to total number of equivalents of acid is about 0.5 to 1.2 and wherein from about 15 to 60 percent of the c-,/3-unsaturated dibasic acid and/or anhydride is available to react with the reactive component.

2. A body putty resin composition according to Claim 1 wherein the c-, 3-unsaturated dibasic acid is maleic acid and the ,β -unsaturated dibasic anhydride is maleic anhydride.

3. A body putty resin composition according to Claim 1 wherein the reactive component is styrene.

4. A body putty resin composition according to Claim 1 wherein the polyhydric alcohol is a glycol.

5. A body putty resin composition according to Claim 4 wherein the glycol is one or more of the glycols selected from the group consisting of ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, 1,3- butanediol, 1,4-butanediol, 1,3 hexanediol, neopentyl glycol, methylpentanediol, 1,3-butylene glycol, 1,6-hexanediol, neopentyl glycol, ethylene oxide adduct of bisphenol, and propylene oxide adduct of bisphenol.

6. A body putty resin composition according to Claim 1 further including a tertiary amine promoter.

7. A body putty resin composition according to Claim 6 wherein the tertiary amine promoter is one or more amines selected from the group . consisting of dimethylaniline, diethylaniline, dimethyl-/->-toluidine, p-to\y\ diethanolamine, and m-tolyl diethanolamine.

8. A body putty resin composition according to Claim 1 further including a free radical peroxide initiator.

9. A curable body putty resin composition suitable for use in repairing metal surfaces, the body putty resin composition comprising:

20 to 50 weight percent of a reactive component which becomes an integral part of the composition on curing; and 50 to 80 weight percent of a polyester formed from an α^*,/3-unsaturated dibasic acid and/or anhydride, a polyhydric alcohol and dicyclopentadiene or derivative thereof, and optionally a saturated dibasic and/or anhydride, wherein a nadic moiety is formed between the c.,0-unsaturated dibasic acid and/or anhydride and cyclopentadiene formed from dicyclopentadiene or derivative thereof, wherein the ratio of total number of equivalents of hydroxy to total number of equivalents of acid is about 0.5 to 1.2 and wherein from about 15 to 60 percent of the α,/3-unsaturated dibasic acid and/or anhydride is available to react with the reactive component.

10. A curable body putty resin according to Claim 9 wherein the α,/3-unsaturated dibasic acid is maleic acid and the anhydride is maleic anhydride.

11. A curable body putty resin according to Claim 9 wherein the reactive component is styrene.

12. A curable body putty resin according to Claim 9 wherein the polyhydric alcohol is a glycol.

13. A curable body putty resin according to Claim 12 wherein the glycol is one or more of the glycols selected from the group consisting of ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, 1,3- butanediol, 1,4-butanediol, 1,3 hexanediol, neopentyl glycol, methylpentanediol, 1,3-butylene glycol, 1,6-hexanediol, neopentyl glycol, ethylene oxide adduct of bisphenol and propylene oxide adduct of bisphenol.

14. A curable body putty resin according to Claim 9 further including a tertiary amine promoter.

15. A curable body putty resin according to Claim 14 wherein the tertiary amine promoter is one or more amines selected from the group consisting of dimethylaniline, diethylaniline, dimethyl- ?-toluidine, -tolyl diethanolamine, and m-tolyl diethanolamine.

16. A curable body putty resin according to Claim 9 further including a free radical peroxide initiator.

17. A galvanized metal surface adhered to which is a cured body putty resin composition comprising:

20 to 50 weight percent of a reactive component which becomes an integral part of the composition on curing, and

50 to 80 weight percent of a polyester formed from an c-,(3-unsaturated dibasic acid and/or anhydride, one or more of a polyhydric alcohol, a combination of a polyhydric alcohol and dicyclopentadiene, or dicyclopentadienyl alcohol, and optionally a saturated dibasic acid and/or anhydride, wherein the ratio of total number of equivalents of hydroxy to total number of equivalents of acid is about 0.5 to 1.2 and wherein from about 15 to 60 percent of the ,β -unsaturated dibasic acid and/or anhydride is available to react with the reactive component.

18. A galvanized metal surface according to Claim 17 wherein the a,β -unsaturated dibasic acid is maleic acid and the c.,/3-unsaturated dibasic anhydride is maleic anhydride.

19. A galvanized metal surface according to according to Claim 17 wherein the reactive component is styrene.

20. A galvanized metal surface according to Claim 17 wherein the polyhydric alcohol is a glycol.

21. A galvanized metal surface according to Claim 20 wherein the glycol is one or more of the glycols selected from the group consisting of ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, 1,3- butanediol, 1 ,4-butanediol, 1,3 hexanediol, neopentyl glycol, methylpentanediol, 1,3-butylene glycol, 1,6-hexanediol, neopentyl glycol, ethylene oxide adduct of bisphenol and propylene oxide adduct of bisphenol.

22. A galvanized metal surface according to Claim 17 wherein the body putty resin composition further includes a tertiary amine promoter.

23. A galvanized metal surface according to Claim 22 wherein the tertiary amine promoter is one or more amines selected from the group consisting of dimethylaniline, diethylaniline, dimethyl-p-toluidine, -tolyl diedianolamine, and m-tolyl diethanolamine.

24. A galvanized metal surface according to Claim 17 wherein the body putty resin composition further includes a free radical peroxide initiator.

25. A galvanized metal surface according to Claim 17 wherein a nadic moiety is formed between the o., 3-unsaturated dibasic acid and/or anhydride and cyclopentadiene derived from dicyclopentadiene.

26. A method of repairing a damaged metal surface comprising the steps of

(a) catalyzing the curing of a body putty resin composition comprising 20 to 50 weight percent of a reactive component which becomes an integral part of the composition on curing, and 50 to 80 weight percent of a polyester formed from an c.,/3-unsaturated dibasic acid and/or anhydride, one or more of a polyhydric alcohol, a combination of a polyhydric alcohol and dicyclopentadiene, or dicyclopentadienyl alcohol, and optionally a saturated dibasic acid and/or anhydride, wherein the ratio of total number of equivalents of hydroxy to total number of equivalents of acid is about 0.5 to 1.2 and wherein from about 15 to 60 percent of the α^*,β-unsaturated dibasic acid and/or anhydride is available to react with the reactive component;

(b) applying the curing body putty resin composition to the damaged metal surface; and

(c) subjecting the damaged metal surface having the body putty resin applied thereto to conditions sufficient to cure the body putty resin and to finish the damaged metal surface.

27. A method according to Claim 26 wherein the a, 3-unsaturated dibasic acid is maleic acid and the c., 3-unsaturated dibasic anhydride is maleic anhydride.

28. A method according to Claim 26 wherein the reactive component is styrene.

29. A method according to Claim 26 wherein the polyhydric alcohol is a glycol.

30. A method according to Claim 29 wherein the glycol is one or more of the glycols selected from the group consisting of ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, 1 ,3-butanediol, 1 ,4- butanediol, 1,3 hexanediol, neopentyl glycol, methylpentanediol, 1,3-butylene glycol, 1,6-hexanediol, neopentyl glycol, ethylene oxide adduct of bisphenol, and propylene oxide adduct of bisphenol.

31. A method according to Claim 26 wherein the body putty resin composition further includes a tertiary amine promoter.

32. A method according to Claim 31 wherein the tertiary amine promoter is one or more amines selected from the group consisting of dimethylaniline, diethylaniline, dimethyl-p-toluidine, -tolyl diethanolamine, and m-tolyl diethanolamine.

33. A method according to Claim 26 wherein the body putty resin composition further includes a free radical peroxide initiator.

34. A method according to Claim 26 wherein the body putty resin composition catalyzed in step (a) includes forming a nadic moiety between the o-,β-unsaturated dibasic acid and/or anhydride and cyclopentadiene derived from dicyclopentadiene .