Process for producing aromatic polyesters having increased degrees of polymerization
AssigneeTeijin Limited
InventorsHiroo Inata, Shunichi Matsumura, Makoto Ogasawara
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Abstract
A process for producing an aromatic polyester having an increased degree of polymerization. The process comprises reacting a hydroxyl-terminated, substantially linear, fiber-forming aromatic polyester having an aromatic dicarboxylic acid as a main acid component at an elevated temperature with a bi-cyclic imino ester compound of formula [I] or formula [II]. According to the process, the molecular chains of the aromatic polyester are bonded to each other by the terminal hydroxyl groups thereof to form rapidly the aromatic polyester having an increased degree of polymerization.
Claims26
A process for producing an aromatic polyester having an increased degree of polymerization which comprises reacting a hydroxyl-terminated, substantially linear, fiber-forming aromatic polyester having an aromatic dicarboxylic acid as a main acid component at an elevated temperature with a bis-cyclic imino ester compound of the formula ##STR19## wherein Y represents a divalent hydrocarbon group which may further contain a hetero atom, X represents a divalent hydrocarbon group which contains 1 or 2 carbon atoms as members of the above imino ester ring and is non-reactive under the reaction conditions, and l is 0 or 1, or of the following formula ##STR20## wherein A represents a grouping of the formula ##STR21## in which R.sup.2 represents a monovalent hydrocarbon group, or a grouping of the formula ##STR22## in which R.sup.2 is as defined above, R represents a tetravalent aromatic group which may further contain a hetero atom, and R.sup.1 represents a monovalent aromatic hydrocarbon which is identical to or different from R.sup.2 ;
- thereby bonding the molecular chains of the aromatic polyester to each other by the terminal hydroxyl groups thereof and forming rapidly said aromatic polyester having an increased degree of polymerization.
A process for producing an aromatic polyester having an increased degree of polymerization, which comprises reacting a substantially linear, fiber-forming aromatic polyester containing terminal carboxyl groups and having an aromatic dicarboxylic acid as a main acid component at an elevated temperature with a carboxyl content reducing agent capable of reacting with said terminal carboxyl groups to form terminal hydroxyl groups and a bis-cyclic imino ester of the formula ##STR23## wherein Y represents a divalent hydrocarbon group which may further contain a hetero atom, X represents a divalent hydrocarbon group which contains 1 or 2 carbon atoms as members of the above imino ester ring and is non-reactive under the reaction conditions, and l is 0 or 1, or of the following formula ##STR24## wherein A represents a grouping of the formula ##STR25## in which R.sup.2 represents a monovalent hydrocarbon group, or a grouping of the formula ##STR26## in which R.sup.2 is as defined above, R represents a tetravalent aromatic group which may further contain a hetero atom, and R.sup.1 represents a monovalent aromatic hydrocarbon which is identical to or different from R.sup.2 ;
- thereby converting the terminal carboxyl groups of said aromatic polyester to terminal hydroxyl groups by said carboxyl content reducing agent and bonding the molecular chains of the aromatic polyesters to each other by the terminal hydroxyl groups, and when low boiling volatile components are formed as by-products during the conversion of the carboxyl groups to the terminal hydroxyl groups, reacting at least said carboxyl content reducing agent and said aromatic polyester in the molten state, thereby forming said aromatic polyester having an increased degree of polymerization rapidly.
A process for producing a molded article composed of an aromatic polyester having an increased intrinsic viscosity, which comprises mixing a hydroxylterminated, substantially linear aromatic polyester having an intrinsic viscosity, measured in o-chlorophenol at 35.degree. C., of at least 0.3 and derived from terephthalic acid as a main acid component and ethylene glycol as a main glycol component, with 0.1 to 1 mole, per equivalent of the terminal hydroxyl groups of said aromatic polyester, of 2,2'-bis(3,1-benzoxazin-4-one) of the formula ##STR27## in a melt-molding machine at a temperature above the melting point of said aromatic polyester, thereby bonding the molecular chains of said aromatic polyester to each other by the terminal hydroxyl groups.
A process for producing an aromatic polyester having an increased intrinsic viscosity, which comprises mixing a hydroxyl-terminated, substantially linear aromatic polyester having an intrinsic viscosity, measured in o-chlorophenol at 35.degree. C. of at least 0.3 and derived from terephthalic acid as a main acid component and an alkylene glycol having 3 to 6 carbon atoms as a main glycol component, with 0.1 to 1 mole, per equivalent of the terminal hydroxyl groups of said aromatic polyester, of at least one member selected from the group consisting of 2,2'-bis(3,1-benzoxazin-4-one), 2,2'-p-phenylenebis[4,4-dimethyl-5(4H)-oxazolone], 2,2'-m-phenylenebis[4,4-dimethyl-5(4H)-oxazolone], 2,2'-p-phenylenebis[3,1-benzoxazin-4-one], 2,2'-p-phenylenebis[4-isobutyl5(4H)-oxazolone], 2,8-dimethyl-4H,6H-benzo(1,2-d:5,4-d')bis(3,1)oxazine-4,6-dione, 2,7-dimethyl-4H,6H-benzo(1,2-d:4,5-d')bis(1,3)oxazine-4,9-dione, and 6,6'-bis(2-methyl-4H,3,1-benzoxazin-4-one) in a melt-molding machine at a temperature above the melting point of said aromatic polyester, thereby bonding the molecular chains of said aromatic polyester to each other by the terminal hydroxyl groups.
Dependencies are inferred from the claim text.