Patent ID: 6948612

Claim:
A seamless conveying belt comprising a polyimide soluble in organic solvents, wherein said polyimide is a compound of the formula (I): wherein R's represent independently from one another a hydrogen atom, a halogen atom, a C 1 -C 10 alkyl group or a C 1 -C 10 alkoxy group, a phenyl group, or a phenyl group which is substituted with 1 to 4 halogen atoms and/or C 1 -C 10 alkyl groups; A is a C 6 -C 20 tetravalent aromatic group or a group of the formula (II): wherein B is a covalent bond, a >C(R 2 ) 2 group, a carbonyl group, an oxygen atom, a sulfer atom, a >SO 2 group, a >Si(CH 3 ) 2 group, a >Si(C 2 H 5 ) 2 group, a >NR 3 group or a bifunctional ether group in which R 2 is a hydrogen atom or C(R 4 ) 3 , R 3 is a hydrogen atom, a C 1 -C 20 alkyl group or a C 6 -C 20 aryl group, and R 4 is a hydrogen atom, a flourine atom or a chlorine atom; Ar is a monocyclic or polycyclic C 6 -C 20 aromatic nucleus or a group of the formula (III): wherein Ar and B are the same as defined above, and each p is an integer of 0 to 10; m is an integer of 1 to 10, and said polyimide has a weight average molecular weight of 150,000 to 1,000,000 in terms of a polystyrene molecular weight measured with gel permeation chromatography.