Pipe made of polyethylene resin
AssigneeMitsubishi Chemical Corporation
InventorsYoshinao Shinohara, Yasuhisa Mizuno, Eiji Tanaka, Yasuhiro Kashiwagi, Miki Suzaki, Koshi Yokoyama
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Abstract
A pipe made of a polyethylene resin which is a linear polyethylene having the following physical properties (1) to (4): (1) a melt flow rate of 0.02 to 0.2 g/10 min, (2) a flow ratio of 50 or more, (3) a density of 0.945 to 0.960 g/cm3, and (4) a relaxation parameter H, represented by the following equation (I), of 2.00×10−8 dyn/cm2 or less: H = - E ( 10 3 ) Log E ( 10 3 ) - Log E ( 10 0 ) Log 10 3 - Log 10 0 ( I ) wherein E(τ) represents a relaxation modulus at time τ.
Claims8
A method of improving the internal pressure creep resistance and environmental stress cracking resistance of a polyethylene pipe, comprising:
- molding a linear polyethylene having the following characteristics:
- (1) a melt flow rate (MFR) of 0.02-02 g/10 min.;
- (2) a flow ratio of 50 or more;
- (3) a density of 0.945-0.960 g/cm3;
- and
- (4) a relaxation parameter H, represented by the following equation (I), of 2.00×10−8 dyn/cm2 or less:
- H = - E ( 10 3 ) Log E ( 10 3 ) - Log E ( 10 0 ) Log 10 3 - Log 10 0 ( I )
- wherein E(τ) represents a relaxation modulus at time τ, into the shape of a pipe.
Dependencies are inferred from the claim text.