Mitsui Chemicals, Inc.

Hideyuki Akieda

Kazuhiko Yoshinaga

Takeshi Ishitoku

Akihiro Funae

Yuzo Ono

Yoshinori Nakahara

Minoru Kajita

Satoru Nakatani

Yoshikatsu Shioya

Kouichi Uchiki

Kazuhiro Ozu

Takuji Matsumoto

A biologically absorbable polyhydroxycarboxylic acid in which a content of water-soluble acid components is not more than 0.07 mol/kg in terms of monobasic acids, and which has a weight average molecular weight of 4,000 to 100,000 and contains neither a catalyst nor an organic solvent, and a production method thereof.

Biologically absorbable polyhydroxycarboxylic acid and production method thereof

The ring opening polymerization of p-dioxanone is started in a liquid phase under stirring at a temperature of 85 to 105&deg; C. after adding 0.002 to 0.005 mol percent of stannous 2-ethylhexanoate forming a white crystal at a temperature of 0&deg; C. as a catalyst and 0.01 to 0.1 mol percent of initiator. Stirring is stopped when a stirring load has increased by 10 to 100 percent over an initial load, while the temperature is lowered to a range of 65 to 85&deg; C., to continue the polymerization in a solid phase to produce poly(p-dioxanone). The polymer is used to make a monofilament having a knot tensile strength of at least 30,000 psi and a strength retention of at least 58 percent after four weeks of immersion in a physiological saline solution at 37&deg; C. The monofilament provides an absorbable surgical suture which is highly resistant to hydrolysis and very useful for stitching a wound or incision which requires a long time for healing.

Method of producing poly(p-dioxanone), poly (p-dioxanone) monofilaments and method for producing the same

Purified salt of &bgr;-hydroxyethoxy acetic acid, purified 2-p-dioxanone, and manufacturing method therefor

A random-block copolymer having appropriate hydrolyzability, excellent flexibility and excellent mechanical strength, a monofilament thereof, and a process for producing the copolymer. The random-block copolymer comprises from 5 to 50 mol % of a random copolymer segment containing from 20 to 80 mol % of a lactide unit (A) and from 80 to 20 mol % of a caprolactone unit (B), and from 95 to 50 mol % of a block copolymer segment containing a glycolide unit (C).

Random-block copolymer and monofilament thereof

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Chiba, Japan

Hideyuki Akieda