the composite plastisol coating composition comprises a polyvinylchloride resin powder , an acrylic resin powder , an acrylic monomer and / or oligomer , a plasticizer , a stabilizer , and a heat setting initiator and a photoinitiator for the acrylic monomer and / or oligomer . the coating composition may also include agents such as pigments , fillers , etc . polyvinylchloride resin , which is one of the main components of the present invention , may include that which is polymerized by micro suspension , emulsion or solution methods . the resin should have an average degree of polymerization of 500 to 2 , 500 ( i . e . the number of repeating monomeric units ), and may include homopolymers , copolymers and partially cross - linked polymers . the monomers used for copolymerization with vinylchloride monomers are , for example , ethylene , propylene , vinyl acetate , vinyl propionate , vinyl stearate , alkyl vinyl ether , vinylidene chloride , di - ethyl fumarate and methacrylate . more than 95 wt % of the polyvinylchloride powder should be composed of particles whose sizes are in the range of 0 . 5 to 40 μm . of that , 20 to 60 wt % should be particles whose sizes are in the range of 0 . 5 to 5 μm and 35 to 75 wt % should be particles whose sizes are in the range of 5 to 40 μm . the distribution curve corresponding to particle size should have 2 peaks in the 1 to 3 μm range and in the 8 to 15 μm range , respectively . although the average particle size of the conventional polyvinylchloride powder for a plastisol coating is 1 to 3 μm as shown in fig1 the present inventors have found it desirable for the polyvinylchloride powder to be composed of particle sizes which give 2 peaks in the distribution curve as shown in fig2 . the present inventors have discovered that more than 5 wt % of polyvinylchloride powder having a particle size of more than 40 μm impairs the appearance of the coating surface . less than 20 wt % of the polyvinylchloride powder having a particle size of 0 . 5 to 5 μm , or more than 75 wt % of the polyvinylchloride powder having a particle size of 5 to 40 μm is found to cause inferior gelation of the plastisol coating . on the other hand , more than 60 wt % of the polyvinylchloride powder having a particle size of 0 . 5 to 5 μm or less than 35 wt % of the polyvinylchloride powder having a particle size of 5 to 40 μm is found to cause high viscosity of the plastisol and thus requires great quantities of plasticizer or diluent to coat metal sheets and to impart softness to the coating . acrylic resin powder , which is another one of the main components according to the present invention , may include that which is polymerized by the micro suspension or emulsion methods , and may include homopolymers of methylmethacrylate , copolymers and partially cross - linked copolymers . the monomers used for copolymerization with methylmethacrylic acid are , for example , vinyl monomers having such functional groups as epoxy , carboxyl , methylol , alkyl amino and amido groups , and multifunctional compounds such as divinyl benzene , ethyleneglycol dimethacrylate and trimethylolpropane trimethacrylate monomers . in the present invention , acrylic resin powder having an average degree of polymerization of 500 to 30 , 000 is desirable . acrylic resin polymers having an average degree of polymerization of less than 500 impair the formability of the coating , and polymers having an average degree of polymerization of more than 30 , 000 impair the gelation of the plastisol coating and cause brittleness of the coating . in these powders , a particle size of more than 0 . 1 μm and less than 40 μm is desirable . an acrylic resin particle size of more than 40 μm results in inferior gelation of the coating , and a particle size of less than 0 . 1 μm causes an high viscosity of the plastisol . acrylic monomers or oligomers , which are another main component according to the present invention , may be liquid chemicals having at least one kind of functional group in a molecule such as acryloyl , methacryloyl and vinyl , and may be polymerized by heating and irradiating with ultraviolet rays . acrylic monomers which may be used in the present invention are , for example , 2 - ethylhexyl acrylate , tetrahydrofurfuryl acrylate , neopentylglycol diacrylate , tri - methylolpropane triacrylate and pentaerytritol triacrylate . acrylic oligomers which may be used in the present invention are , for example , polyol acrylate , polyesteracrylate , epoxy acrylate and urethane acrylate . a mixture of the above - mentioned acrylic monomers and oligomers may also be used in the present invention . the heat setting initiator for acrylic monomers and oligomers may include several kinds of organic peroxides , and the photoinitiator for acrylic monomers and oligomers may include , for example , benzoin benzyl , benzoin ethylether and benzophenone . a mixture of the above - mentioned heat setting initiators and photoinitiators may also be used , and the amount should be 0 . 1 to 5 parts per 100 parts of the acrylic monomers and / or oligomers . plasticizers , stabilizers , pigments and other additives , which are additional components of the present invention , may include those used in conventional polyvinylchloride plastisol coatings . ______________________________________polyvinylchloride powder 100 partsacrylic resin powder 5 ˜ 60acrylic monomer and / or oligomer 5 ˜ 60heat setting initiator 0 . 05 ˜ 3photoinitiator 0 . 05 ˜ 3plasticizer as neededstabilizer as neededpigment as neededdiluent as needed______________________________________ the above amounts and those amounts described in the specification refer to parts by weight , unless otherwise specified . the amount of acrylic resin powder and acrylic monomer and / or oligomer must not be over 60 parts or under 5 parts of either component , because the addition of over 60 parts impairs the embossing finish , while the addition of less than 5 parts has no effect . next , the process for obtaining the coated metal sheets of the present invention will be described . a steel sheet , an electrogalvanized steel sheet , a hot dip galvanized steel sheet or an electrolytic chromate treatment steel sheet , etc ., are used as the substrate steel sheet . a well known adhesive for polyvinylchloride - metal coated steel , such as an acrylic - type , epoxy - type , urethane - type or a rubber - type , etc ., is used as the adhesive . the substrate steel sheet is typically precoated with adhesive , baked by a heat treatment and covered with the composite polyvinylchloride plastisol of the present invention . the substrate steel sheet with adhesive is coated with this composite polyvinylchloride plastisol by roll coating , dipping , knife coating or curtain coating , etc ., and then baked at 150 ° to 250 ° c . for gelation and adhesion , after which the embossing finish is applied . in certain instances , the coated metal sheet is irradiated by ultraviolet rays after the heating and embossing the coating . the wavelength of the ultraviolet rays may be 200 to 400 μm and the ultraviolet rays may be generated by a mercury lamp , a xenon electronic - flash lamp or a carbon arc lamp . the irradiation should be done after heating and embossing the coating , because irradiation done before heating and embossing the coating causes an inferior embossing surface . the detailed effects of the present invention will be further explained by the following examples . a zn - co - mo coelectrogalvanized steel sheet of 0 . 5mm thickness was coated with an epoxy - type adhesive 5 μm in thickness by a bar coater and heated in a hot air oven for 30 seconds at 300 ° c . the temperature of the steel sheet was 230 ° c . then the steel sheet was cooled . the steel sheet was then coated with the composite polyvinylchloride plastisol shown in table 1 150 μm in thickness by a knife coater and heated in a hot air oven for 60 seconds at 260 ° c . and immediately thereupon received an embossing finish by an engraved pebbling roll having a roughness of 7 . 1 μm in average roughness and 45 . 0 μm in maximum roughness . examples 2 - 6 of the present invention were produced according to the same procedure as example 1 , except for the substitution of the composite polyvinylchloride plastisol compositions shown in table 1 and the irradiation of the coating surface by ultraviolet rays ( lamp : h2000l / 6 , toshiba denzai co ., ltd .) after heating and embossing the coating . the evaluation of the properties of the coatings described in the examples are summarized in table 3 . comparative example 1 was produced according to the same procedure as example 1 , except for the substitution of the composite polyvinylchloride plastisol composition shown in table 2 . comparative example 2 was performed according to japanese laid - open patent application no . sho . 54 - 50549 and was produced by the same procedure as example 1 , except for the substitution of the composite polyvinylchloride plastisol composition shown in table 2 . comparative examples 3 and 5 were also produced by the same procedure as example 1 , except for the substitution of the composite polyvinylchloride plastisol compositions shown in table 2 . comparative example 4 was performed according to japanese laid - open patent application no . sho . 63 - 185630 and was produced by the same procedure as example 2 , except for the substitution of the compositive polyvinylchloride plastisol composition shown in table 2 . the evaluation of the properties of the comparative examples are summarized in table 3 . as mentioned in table 3 , the composite polyvinylchloride plastisol coated steel sheet according to the present invention has a coating of high hardness and shows excellent formability , embossing finish , impression resistance and bleed resistance . the polyvinylchloride powders and acrylic resin powders used in the examples and comparative examples are described in detail as followed : the polyvinylchloride coated steel sheets , which were prepared in examples 1 - 6 and comparative examples 1 - 5 , were evaluated by the following test methods . the results are shown in table 3 . ( 1 ) viscosity of the polyvinylchloride plastisol was measured by a bm - type viscotester ( tokyo keiki co ., ltd .). ( 2 ) hardness of the coating was measured by a a - type duro meter ( shimadzu co ., ltd ). a sample steel sheet was subjected to the dupont impact test ( 1 / 2 &# 34 ;× 1 kg × 50 cm ) at temperatures of - 5 ° c ., 0 ° c . and 5 ° c . the sheets were evaluated and the following symbols are used to describe the results of the test . 60 ° specular glossiness was measured by a glossimeter ugx - 5 ( suga test instruments co ., ltd .) a sample steel sheet was subjected to the surface roughness tester surfcom 60a ( tokyo seimitsu co ., ltd . ), and average roughness ( ra ) and maximum roughness ( rmax ) were shown . sample steel sheets , 15 × 15 cm in size , were piled up and were subjected to the load test ( 40 ° c .× 3 kg / cm 2 × 10 day ). after that , the embossing pattern of the coating was evaluated . sample steel sheets and polyester films of 20μm in thickness , 15 × 15 cm in size , were piled up one after another and were subjected to the load test ( 50 ° c .× 10kg / cm 2 × 10 day ). after that , bleeded materials on the polyester film surface from the coating were observed . table 1______________________________________ plastisol viscosityexample plastisol composition ( parts ) ( poise ) ______________________________________1 pvc a 87 260 acrylic resin a 13 acrylic oligomer ( aronix m - 8060 , 15 toagosei co ., ltd .) organic peroxide ( perhexsa 0 . 3 3m , nipponushi co ., ltd .) plasticizer ( dop ) 30 plasticizer ( cs - 16 , chisso co ., ltd .) 10 stabilizer ( pb - type ) 2 pigment ( carbon black ) 1 . 52 pvc a 91 250 acrylic resin a 9 acrylic oligomer ( aronix m - 8060 , 15 toagosei co ., ltd .) photoinitiator ( darocure no . 1116 , 0 . 45 merk co ., ltd .) plasticizer ( dop ) 30 plasticizer ( cs - 16 , chisso co ., ltd .) 10 stabilizer ( pb - type ) 2 pigment ( carbon black ) 1 . 53 pvc a 80 260 acrylic resin a 20 acrylic monomer ( tmpt , 10 shinnakamura chemical co ., ltd .) photoinitiator ( darocure no . 1116 , 0 . 35 merk co ., ltd .) organic peroxide ( perhexsa 0 . 05 3m , nipponushi co ., ltd .) plasticizer ( dop ) 30 plasticizer ( cs - 16 , chisso co ., ltd .) 10 stabilizer ( pb - type ) 2 pigment ( carbon black ) 1 . 54 pvc a 77 250 acrylic resin b 23 acrylic oligomer ( aronix m - 400 , 15 toagosei co ., ltd .) photoinitiator ( darocure no . 1116 , 0 . 45 merk co ., ltd .) plasticizer ( dop ) 30 plasticizer ( cs - 16 , chisso co ., ltd .) 10 stabilizer ( pb - type ) 2 pigment ( carbon black ) 1 . 55 pvc a 77 200 acrylic resin c 23 acrylic oligomer ( aronix m - 400 , 15 toagosei co ., ltd .) photoinitiator ( darocure no . 1116 , 0 . 45 merk co ., ltd .) plasticizer ( dop ) 30 plasticizer ( cs - 16 , chisso co ., ltd .) 10 stabilizer ( pb - type ) 2 pigment ( carbon black ) 1 . 56 pvc b 77 300 acrylic resin a 23 acrylic oligomer ( aronix m - 8060 , 15 toagosei co ., ltd .) photoinitiator ( darocure no . 1116 , 0 . 45 merk co ., ltd .) plasticizer ( dop ) 45 stabilizer ( organic sn compound ) 2 pigment ( titanium white ) 5______________________________________ table 2______________________________________ plastisolcomparative viscosityexample plastisol composition ( parts ) ( poise ) ______________________________________1 pvc a 100 300 plasticizer ( dop ) 30 plasticizer ( cs - 16 , chisso co ., 15 ltd .) stabilizer ( pb - type ) 2 pigment ( carbon black ) 1 . 52 pvc a 100 280 acrylic oligomer ( aronix 15 m - 8060 , toagosei co ., ltd .) photoinitiator ( darocure 0 . 60 no . 1116 , merk co ., ltd .) plasticizer ( dop ) 35 stabilizer ( pb - type ) 2 pigment ( carbon black ) 1 . 53 pvc a 100 260 acrylic monomer ( tmpt , 20 shinnakamura chemical co ., ltd .) organic peroxide ( perhexsa 3m , 0 . 6 nipponushi co ., ltd .) plasticizer ( dop ) 30 stabilizer ( pb - type ) 2 pigment ( carbon black ) 1 . 54 pvc a 80 290 acrylic resin a 20 plasticizer ( dop ) 30 plasticizer ( cs - 16 , chisso co ., 10 ltd .) stabilizer ( pb - type ) 2 pigment ( carbon black ) 1 . 55 pvc b 100 330 plasticizer ( dop ) 45 stabilizer ( organic sn 2 compound ) pigment ( titanium white ) 5______________________________________ table 3__________________________________________________________________________ filmsample hardness form - embossing impression bleedno . ( duro a ) ability gloss ra ( mm ) rmax ( mm ) resistance resistance__________________________________________________________________________example1 94 o 6 3 . 3 29 . 6 o o2 95 o 6 3 . 5 30 . 5 o o3 97 δ 5 3 . 3 29 . 5 o o4 95 o 7 3 . 6 31 . 5 o o5 92 o 4 3 . 8 35 . 6 o o6 87 o 10 3 . 6 32 . 5 o ocompara - tiveexample1 90 δ 10 3 . 5 30 . 3 x x2 92 x 12 3 . 4 30 . 0 x δ3 91 x 11 1 . 7 17 . 5 x δ4 92 o 6 2 . 6 26 . 5 δ δ5 76 o 13 3 . 7 32 . 7 x x__________________________________________________________________________