Abstract: Provided are: a mold release film, which has excellent mold releasability to a semiconductor resin package and does not easily generate warpage, wrinkles and the like; and a method for obtaining a semiconductor resin package having excellent dimensional accuracy by using such mold release film. The mold release film for manufacturing a semiconductor resin package has one or more base material layers (C), a pair of outermost layers (A) which sandwich the base material layers (C) and contain a 4-methyl-1-pentene polymer as a main component, and a pair of adhesive layers (B) which adhere together the base material layers (C) and the outermost layers (A).

Abstract: Disclosed herein is a release paper comprising: a paper base laminated with a release layer, this release layer comprising a 4-methyl-1-pentene resin being a copolymer of 4-methyl-1-pentene and an &agr;-olefin other than 4-methyl-1-pentene wherein the &agr;-olefin is contained in a proportion of 6 to 8% by weight. This release paper is excellent in heat resistance and exhibits less curling tendency in repeated use. Further, the release paper exhibits a high bonding strength between resin and paper, and is excellent in durability. The release paper is suitable for use in, for example, production of a synthetic leather.

Abstract: The present invention relates to 4-methyl-1-pentene polymer compositions. Specifically, the present invention relates to adhesive compositions comprising the 4-methyl-1-pentene polymers used in bonding a 4-methyl-1-pentene polymer layer and a polar-group-containing resin layer, and laminates obtained by using such compositions. The 4-methyl-1-pentene polymer compositions as these adhesive compositions comprise a 4-methyl-1-pentene polymer (A); and a modified polyolefin resin (B) comprising a mixture of an unsaturated carboxylic acid-modified a-olefin polymer (B-1) whose &agr;-olefin is selected from a group of propylene, butene-1 and 4-methyl-1-pentene and an unsaturated carboxylic acid-modified ethylene-&agr;-olefin copolymer (B-2). In these compositions, an unsaturated carboxylic acid-modified 4-methyl-1-pentene polymer (A′) showing a particular modification rate and a particular melt flow rate may be used in place of (A) and (B-1).

Abstract: Disclosed herein is a release paper comprising:

Abstract: The present invention relates to 4-methyl-1-pentene polymer compositions. Specifically, the present invention relates to adhesive compositions comprising the 4-methyl-1-pentene polymers used in bonding a 4-methyl-1-pentene polymer layer and a polar-group-containing resin layer, and laminates obtained by using such compositions. The 4-methyl-1-pentene polymer compositions as these adhesive compositions comprise a 4-methyl-1-pentene polymer (A); and a modified polyolefin resin (B) comprising a mixture of an unsaturated carboxylic acid-modified .alpha.-olefin polymer (B-1) whose .alpha.-olefin is selected from a group of propylene, butene-1 and 4-methyl-1-pentene and an unsaturated carboxylic acid-modified ethylene/.alpha.-olefin copolymer (B-2). In these compositions, an unsaturated carboxylic acid-modified 4-methyl-1-pentene polymer (A') showing a particular modification rate and a particular melt flow rate may be used in place of (A) and (B-1).

Abstract: Disclosed is a laminated film or sheet comprising poly-4-methyl-1-pentene laminated on a paper layer. By using poly-4-methyl-1-pentene having a low melting point, formation of cracks and other defects in the resin layer is prevented and the oil and fat impermeability is improved. If an intermediate layer of a specific polymer is formed in addition to the poly-4-methyl-1-pentene layer, the oil and fat impermeability is further improved. A box-shaped vessel (carton) and a release paper for an artificial leather can be prepared from this laminated film or sheet.

Abstract: Disclosed is a laminated film or sheet comprising poly-4-methyl-1-pentene laminated on a paper layer. By using poly-4-methyl-1-pentene having a low melting point, formation of cracks and other defects in the resin layer is prevented and the oil and fat impermeability is improved. If an intermediate layer of a specific polymer is formed in addition to the poly-4-methyl-1-pentene layer, the oil and fat impermeability is further improved. A box-shaped vessel (carton) and a release paper for an artificial leather can be prepared from this laminated film or sheet.

Abstract: A modified .alpha.-olefin polymer whose side chain has tertiary carbon, obtained by melt-reacting 100 parts by weight of (A) an .alpha.-olefin polymer whose side chain has tertiary carbon with (B) 0.05 to 10 parts by weight of metal methacrylate or metal acrylate of the formula (1), ##STR1## wherein R is a hydrogen atom or a methyl group, M is a metal cation, X is an anion, m is an integer of at least 2, and n is an integer of at least 2, with a proviso of m.gtoreq.n; and a stretched film thereof.