Patent ID: 7767313

Claim:
A polypropylene composite film comprising: (I) a crystalline polypropylene layer and (II) a layer of a polypropylene composition laminated on at least one surface of the layer (I), wherein the polypropylene composition comprises: 0 to 95% by weight of a crystalline polypropylene (PP-A) and 5 to 100% by weight of a propylene/1-butene random copolymer (PBR): (1) containing 60 to 90 mol % of units derived from propylene and 10 to 40 mol % of units derived from 1-butene, and having (2) a triad isotacticity, as determined from a 13 C-NMR spectrum, of not less than 85% and not more than 97.5%, (3) a molecular weight distribution (Mw/Mn), as determined by gel permeation chromatography (GPC), of from 1 to 3, (4) an intrinsic viscosity, as measured in decalin at 135° C., of from 0.1 to 12 dl/g, (5) a melting point (Tm), as measured on a differential scanning calorimeter, of from 40 to 75° C., (6) a crystallization rate (½ crystallization time) at 45° C. of 10 minutes or less when a melting point (Tm) is 75° C. or below, and satisfying (7) the following relation 146 exp (−0.022M)≧ Tm≧ 125 exp(−0.032M) wherein Tm represents a melting point and M (mol %) represents a content of 1-butene constituent units and obtained by polymerizing propylene and 1-butene in the presence of an olefin polymerization catalyst comprising: a transition metal compound (1a) represented by the following formula (1a): wherein R 3 is a hydrocarbon group or a silicon-containing group; R 1 , R 2 and R 4 , which may be the same or different, are each a hydrogen atom, a hydrocarbon group or a silicon-containing group; R 5 , R 6 , R 7 , R 8 , R 9 , R 10 , R 11 , R 12 , R 13 and R 14 , which may be the same or different, are each a hydrogen atom, a hydrocarbon group or a silicon-containing group; neighboring substituent groups of R 5 to R 12 may link together to form a ring; R 13 and R 14 , which may be the same or different, may link together to form a ring; M denotes a Group-4 transition metal; Y denotes a carbon atom; Q denotes a halogen atom, a hydrocarbon group, an anionic ligand or a neutral ligand capable of coordination by a lone pair of electrons, and may be the same or different when plural; and j is an integer of 1 to 4, an organoaluminum oxy-compound (1b) and/or a compound (2b) capable of forming an ion pair by reacting the transition metal compound (1a) and optionally an organoaluminum compound (c).