Patent ID: 6173237
Filing Date: 2001-01-09
Classification: C08L,G01N

Abstract:
A process for obtaining a bitumen/polymers mixture for the production of roofing sealing membranes, wherein the mixture exhibits a selected physical characteristic, and wherein the process comprises the steps of;producing a number of bitumen/polymers mixtures wherein the polymers and the bitumen are identical in all the mixtures and wherein the respective percentages of the polymers and bitumen vary from mixture to mixture,measuring said physical characteristics for each of said mixtures,producing a model of the said physical characteristics in the form of:TR=A+B*IPP+C*APP1+D*COPO3+E*IPP*COPO2,Pen25.degree. C.=F-G*IPP-H*APP1,Pen60.degree. C.=I-J*TPP-K*APP1-L*IPP*APP1,Ln(Visc180.degree. C.)=M+N*IPP+P*APP1+O*COPO1+R*COPO2+S*COPO3+T*IPP*APP1+U*IPP*COPO2,FBT=V+W*IPP-X*APP2-Z*COPO1, andFBT4=X+A1*IPP-A2*APP2-A3*COPO1-A4*COPO2,each of A, B, C, D, E, F, G, H, I, J, K, I, L, M, N, P, O, R, S, T, U, V, W, X, Y, Z, A1, A2, A3, and A4 being determinable constants,TR represents a softening temperature having units of degrees Celsius,IPP represents an isotactic Polypropylene expressed as a % weight of the total mixture,APP1 represents a first atactic polypropylene expressed as a percent weight of the total mixture,APP2 represents a second atactic polypropylene expressed as a percent weight of the total mixture,COPO1 represents a first copolymer expressed as a percent weight of the total mixture,COPO2 represents a second copolymer expressed as a percent weight of the total mixture,COPO3 represents a third copolymer expressed as a percent weight of the total mixture,Pen25.degree. C. represents penetration at 25.degree. C. expressed with units of deci mm,Pen60.degree. C. represents penetration at 60.degree. C. expressed with units of deci mm,Visc180.degree. C. represents a Brookfield viscosity at 180.degree. C. expressed with units of CP,FBT represents flexibility at a low temperature in mint condition expressed with units of degrees Celsius, andFBT.sub.4 represents flexibility at a low temperature in aged condition expressed with units of degrees Celsius,fixing a range of values for the said characteristics,deriving the percentage of each polymer in the mixture,determining the influence of the percentage of the different polymers of said mixtures on at least one physical characteristic of the mixture,determining physical characteristics of the bitumen/polymers mixture to be obtained according to the polymers used by fixing the percentages of each polymer used,and producing a batch of roofing sealing material having a composition according to a selected one of said determined physical characteristics.