text: the present invention involves a polyester primer , resin , filler , adhesive , or putty that can be applied to metal substrates , such as cold rolled steel , galvanized steel , and aluminum , as well as to plastic substrates , such as polyesters , polyurethanes , polyolefins , sheet molding compounds ( smc ), and bulk molding compounds ( bmc ). the goal was to identify a carrier for the catalyst which will not react with the catalyst , which can be stabilized in the presence of peroxides , and which will be a reactive component in the system by crosslinking with the unsaturated polyester effectively , maintaining an integral cure . at a minimum , the carrier should not impede the cure of the unsaturated polyester . the material should be of a reasonable viscosity so as to be practical for dispensing and mixing . in addition , it should be stable in the presence of peroxides for long periods , such as more than six months , or more than one year , or longer . the present invention involves the use of a reactive carrier , rather than a non - reactive carrier , such as phthalate plasticizers . the use of a reactive carrier greatly increases the challenge of stabilization of the blend . it will be a reactive component in the system , but it can be stabilized in the presence of the catalyst alone . preferably , the reactive carrier is a epoxy resin . when combined with the resins that are sufficiently thinned with reactive diluent , it can provide an integral cure with a catalyst dispersion level up to about 100 parts per hundred resin or filler by weight . the ability to measure the mix ratio of catalyst to resin accurately will reduce or eliminate the most common problems associated with unsaturated polyester repair product use , and will increase the value of the product to the user . the invention involves the use of peroxide catalysts dispersed in a reactive carrier , such as an epoxy resin , to be used as the hardener side for a two - part resin system . suitable epoxy resins include , but are not limited to , diglycidal ether bisphenol a , diglycidal ether bisphenol f , and epoxylated novolac resins , or combinations thereof . this invention may be used in combination with the invention described in u . s . application ser . no . 11 / 178 , 652 ( u . s . publication no . 2007 / 0010608 ), which is incorporated herein by reference , where a non - diluted unsaturated polyester resin is specified as a suitable reactive carrier . as described there , the unsaturated polyester should have a sufficiently low molecular weight that the viscosity is practical in the absence of a reactive diluent . generally , the viscosity is less than about 10 , 000 cps . most unsaturated polyesters are solids at room temperature in a non - diluted state . however , unsaturated polyesters designed for pigment dispersion have very low molecular weight . examples include , but are not limited to , non - diluted , low viscosity maleate - based or fumarate - based unsaturated polyesters . the epoxy resin and the non - diluted unsaturated polyester resin may be combined in any ratio to be used as the reactive carrier for the peroxide . suitable peroxide catalysts include , but are not limited to , ketone peroxides , cumyl hydroperoxides , dibenzoyl peroxides , peroxyesters , peroxyketals , and peroxydicarbonates . suitable ketone peroxides include , but are not limited to , methyl ethyl ketone peroxide , 2 , 4 - pentadione peroxide , methyl isobutyl ketone peroxide , acetyl acetone peroxide , cyclohexanone peroxide , or combinations thereof . the hardener side can also include fillers such as talcs , carbonates , pigments , rheological modifiers , microspheres , pigment wetting and dispersing agents , paraffins , and fiber reinforcements , or combinations thereof . the resin side of the system can include a reactive polymer , or a monomer , or a combination of the two . suitable reactive polymers include , but are not limited to , unsaturated polyesters , vinyl esters , and hybrid epoxy - polyester and acrylate - polyester systems that polymerize by way of a free radical mechanism , or combinations thereof . suitable monomers include , but are not limited to , styrene , vinyl toluene , other methyl styrene monomers , methyl methacrylate , and other acrylate monomers , or combinations thereof . the resin side can also include fillers such as talcs , carbonates , pigments , rheological modifiers , silica , microspheres , pigment wetting and dispersing agents , paraffins , and fiber reinforcements , or combinations thereof . the fillers can be included in the hardener side and the resin side so that the volume of the two compositions are approximately the same . the ratio of the volume of the hardener side to the volume of the resin side is generally about 1 : 10 to about 1 : 1 , typically about 1 : 10 to about 1 : 2 . with the volume ratio in this range , it is much easier to provide the correct amount of hardener for the amount of resin used , eliminating the guesswork of prior art systems . controlling the volume of each side will allow the use of a variety of mixing tube applicators . one example of a mixing tube applicator is a double barrel mixing tube which has the hardener composition on one side and the resin composition on the other side . the plunger dispenses the hardener composition and resin composition in the proper amounts so that they can be mixed and applied . another suitable mixing tube applicator is a “ universal cartridge .” the universal cartridge incorporates both sides of the product in a single barrel . it uses front and back chambers with a transfer tube from the back to deliver both sides in the correct ratio . the benefit of a universal cartridge is the ability to use it with any caulk gun , instead of specific side by side guns . suitable universal cartridge delivery systems are described in u . s . pat . nos . 5 , 310 , 091 and 6 , 938 , 797 . in order that the invention may be more readily understood , reference is made to the following examples which are intended to illustrate the invention , but not limit the scope thereof . the hardener ( peroxide dispersion ) side of the system was prepared using different reactive carriers : 1 — short chain dipropylene glycol ( dpg ) maleate that is non - diluted with monomer ; 2 — dipentaerythritol pentacrylate monomer ; and 3 — diglycidyl ether bisphenol a . two methyl ethyl ketone peroxide solutions with 9 % active oxygen ( 1 and 2 ) were used , as well as a 50 % benzoyl peroxide paste ( 3 ). raw material a b c d e f reactive 85 . 7 79 . 0 62 . 8 62 . 7 carrier 1 reactive 53 . 2 53 . 2 carrier 2 reactive 18 . 8 18 . 8 14 . 8 14 . 8 carrier 3 peroxide 1 14 . 3 21 . 0 22 . 4 22 . 4 peroxide 2 28 . 0 peroxide 3 28 . 0 antioxidant 1 0 . 02 total 100 100 100 100 100 100 shelf stability & gt ; 1200 & gt ; 1200 7 days 20 days & gt ; 1200 & gt ; 1200 days days days days the use of an acrylate monomer ( formulations c and d ) broke down the stability of the mixture with both benzoyl peroxide and methyl ethyl ketone peroxides . the gel time of several samples was measured at high temperature ( i . e ., 110 ° c ., and 105 ° c .) over 40 days . a hardener composition containing bisphenol a epoxy resin was tested with three resin compositions as shown below . 1 2 3 resin composition unsaturated polyester resin 0 . 545181 0 . 440443 0 . 582093 wetting agent 0 . 005862 0 . 00484 rheological modifier 0 . 004807 0 . 012099 adhesion promoter 0 . 019827 0 . 010966 0 . 013309 tio 2 0 . 048065 0 . 009969 0 . 024198 talc 0 . 298005 0 . 466364 0 . 317483 microspheres 0 . 084114 0 . 066396 0 . 045977 1 1 1 hardener raw material epoxy resin 0 . 4878 benzoyl peroxide paste 0 . 4065 fumed silca 0 . 0407 microspheres 0 . 0650 1 . 0000 the results , which appear in table 1 , showed that the peroxide was stabilized in epoxy resin in the presence of fillers such as microspheres . a sample of the hardener of example 2 was evaluated using the self accelerated decomposition test ( sadt ) performed according to test h1 . 1 of the united nations orange book . the sample had a sadt greater than or equal to 55 ° c . 1 : 10 1 : 4 1 : 2 1 : 1 resin composition styrenated unsaturated 43 . 74 35 . 23 28 . 28 24 . 33 polyester resin monomer 8 . 75 12 . 92 16 . 06 17 . 92 wax 0 . 07 0 . 07 0 . 07 0 . 07 tetrahydrophthalic acid 1 . 94 1 . 88 1 . 81 1 . 77 tio 2 2 . 43 2 . 35 2 . 26 2 . 21 rheological modifier 0 . 49 0 . 47 0 . 45 0 . 44 microtalc 13 . 37 12 . 92 12 . 44 12 . 16 calcium carbonate 12 . 15 11 . 75 11 . 34 11 . 06 microspheres 8 . 51 5 . 87 4 . 52 1 . 66 hardener composition reactive carrier 4 . 86 11 . 74 16 . 97 19 . 91 microspheres 1 . 22 2 . 35 3 . 39 6 . 08 benzoyl peroxide ( 50 %) 2 . 43 2 . 35 2 . 26 2 . 21 total 100 . 00 100 . 00 100 . 00 100 . 00 having described the invention in detail and by reference to specific embodiments thereof , it will be apparent that modifications and variations are possible without departing from the scope of the invention defined in the appended claims . more specifically , although some aspects of the present invention are identified herein as preferred or particularly advantageous , it is contemplated that the present invention is not necessarily limited to these preferred aspects of the invention .