GB1329298A - Articles having a pressure-sensitive layer - Google Patents

Abstract

1329298 Articles with pressure sensitive bitumen-polymer compositions SHELL INTERNATIONALE RESEARCH MAATSCHAPPIJ BV 24 Nov 1970 55866/70 Headings C3N and C3P An article has a pressure-sensitive layer having a viscosity between 5000 and 500,000 poises at 25‹ C. and consisting of a mixture comprising (I) a bituminous component with a penetration at 25‹ C. of 130-2000, the aromaticity of said bituminous component expressed as the fraction of aromatic carbon of the n-heptane maltene phase (f a ) being higher than 0À004 x P + 0À280, in which P represents the content of n-heptane asphaltenes in the bituminous component, and (II) a block copolymer having the general formula A-B-A, in which the two A's represent identical or different thermoplastic, non-elastomeric polymer blocks prepared by polymerization of one or more monovinyl aromatics and in which B represents an elastomeric polymer block which is optionally partly or completely hydrogenated, the weight ratio between the bituminous component and the block copolymer being 95À5/4À5 and 76À5/23À5, whilst there is a relation between said penetration at 25‹ C. of the bituminous component and said block polymer content, so that the mixture falls within the area delimited by the sides of the quadrilateral ABCD in the figure shown in the accompanying drawing, in which figure the Y-axis represents the penetration i.e. 0À1 mm. at 25‹ C. of the bituminous component and the X-axis the weight ratio between the block copolymer and the bituminous component in the mixture, the vertices of the quadrilateral carrying the co-ordinates A (4À5/95À5; 130), B (7À5/92À5; 2000), C (23À5/76À5; 2000), and D (13À5/86À5; 200). The bituminous component may be a precipitation bitumen, a distillation bitumen, a blend of a distillation bitumen and a precipitation bitumen, a mixture of a precipitation bitumen and an aromatic petroleum extract, or a mixture of a propane bitumen and an aromatic extract of a heavy lubricating oil. The bituminous component may also be blended with petroleum pitch or coal tar. Suitable block copolymers are polystyrene-polyisoprenepolystyrene, polystyrene - polybutadienepolystyrene, polystyrene - partly hydrogenated polyisoprene - polystyrene, polystyrenestyrene / butadiene copolymer - polystyrene, and polystyrene-hydrogenated polyisoprenepolystyrene. The mixture may also contain fillers and pigments such as chalk, gypsum, diatomaceous earth and quartz flour. The article having the pressure-sensitive layer is preferably a sheet of roofing material. The composition may be applied as a melt and thickness of the layer is generally 0À0025-0À9 cm. Examples refer to the use of compositions based on a styrenebutadiene-styrene block copolymer and as bituminous component a mixture of a precipitation bitumen and aromatic extract.